JPRS ID: 10710 USSR REPORT ENGINEERING AND EQUIPMENT

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APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00854R000500090007-0 FOR OFFICIAL USE ONLY JPRS,L/.10710 4 August1982 USSR Report ENGINEERING AND EQUIPMENT C F.O U O. 8[8 2)'FgI-S FOREIGN BROADCAST INFORMATION SERVICE FOR OFFICUL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407/02109: CIA-RDP82-00850R000500490007-4 NOTE JPRS publications contain information primarily from foreign newspapers, periodicals and books, but also from news agency transmissions and broadcasts. Materials from foreign-language sources are translated; those from English-language sources are transcribed or reprinted, with the original phrasing and other characteristics retained. _ Headlines, editorial reports, and material enclosed in brackpts are supplied by JPRS. Processing indicators such as [Text] or [ExcerptJ in the first line of each item, or following the last line of a brief, indicate how the original information was processed. Where no processing indicator is given, the infor- mation was summarized or extracted. Unfamiliar names rendered phonetically or transliterated are enclosed in parentheses. Words or names preceded by a ques- tion mark and enclosed in parentheses were not clear in the original but have been supplied as appropriate in context. Other unattributed parentheticai notes within the body of an item originate with the source. Times within litems are as given by source. The contents of this publication in no way represent the poli- cies, views or attitudes of the U.S. Government. C4PYRIGHT LAWS AND REGULATIONS GOVERNING OWNERSHIP OF MATERIALS REPRODUCED HEREIN REQUIIL: THAT DISSEMINATION OF THIS PUBLICATION BE RESTRICTED FOR OFFICIAL USE ONL,Y. APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102/09: CIA-RDP82-00850R000500090007-4 FOR OFFiCIAL USE ONLY JPRS L/1G?10 4 August 1982 USSR REPORI' ENGINEERING AND EGIUIPMENT (FOUO 5/8i; CONTENTS AERONAU'I'ICAL AND SPACE Gas Generators of Rocket Systems 1 NUCLEAR ENERGY Current State and Outlook for HTGR Research in USSR............. 3 Some Requirements for Nuclear-Chemical Facilities With High-Temperature Reactors..................................... 12 Particulars of Layout and Constructian of Experimental Industrial High-Temperature Gas-Cooled Reactor ModQl.......... 18 Choosing Design Concept and Physical Features of HTGR Core for Energy Facilities......................................... 22 Molten-Salt Reactor With Natural Convection of Fuel Mixture and Open Gas-Turbine Air Cycle 28 Physical Features of HTGR With Circulating Fuel 36 Some Problems of Heat Exchange and Hydrodynamics in HTGR Core Components (Survey) 43 Some Results of Experimental Research on HTGR Equipment Components 50 Fabrication and Quality Control of Coated Fuel Particles, Fuel Elements and Fuel Assemblies for HTGR's.................. 61 Transposing Fuel Assemblies To Equalize Energy Distribution and Improve Fuel Cycle in RBMK Reactors....................... 84 - a- [III - USSR - 21F S&T FOUO] APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102/09: CIA-RDP82-00850R000500090007-0 FOR OFFICIAL USE ONLY NON-NUCLEAR ENERGY Energy-Storing Substances and Their Utilization................. 92 Reliability of Electrical Machinery for Power Generation........ 94 NAVIGATION AND GUIDANCE SYSTEMS Navigation and Controlling Movement~ of Mechanical Syetems....... 102 ~ Control System for Elastic Moving Objects 10 HIGH-ENERGY DEVICES, OPTICS AND PHOTOGRAPHY Optical Devices for Measuring Surface Roughness 114 FLUID MECHANICS Hydrodynamic Theory of Lubrication and Analysis of Plain Bearings Operating Under Stationary Conditions.... 116 120 Increasing Heat Exchange Efficiency in Power Equipment.......... Applied Problems'in Hydromechanics.....94 ���4�9�009 129 riECHANICS OF SOLIDS Oscillations of Kinematically-Driven Mechanical Systems 13E Considering Energy Dissipation Two-Dimensional Vibration Impact Systems: Dynamics and Stability 138 - b - FOR OFF[CIAI. USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102/09: CIA-RDP82-00850R000500490007-4 F'OR OFFICIAL USE ONLY AERONAUTICAL AND SPACE UDC 629.7.064.2 GAS GIIdgtATORS OF ROCKET SYSTENS Moscow GAZOGIIJERATORY RAKETNYKH 5ISTEM in Russlan 1981 (signed to press 14 Aug 81) PP 2-4 [Annotation and foreword from book "Gas Generators of Rocket Systems", by A1'bert Alekseyevich Shishkov and Boris Vasil'yevich Rumyantsev, Izdatel'stvo "Mas}iinostroyeniye", 1183 copies, 152 pages] [Textl Annotation This book gives a systematized description of the basic arrangements,chaxact eris- t ics and spec3al features of the operating procasses in gas generators ubing chemical fuels (liquid, solid and mixed) for use as power sources and gas jets aboard aircraft and in ground systems of rocket equipment. Methods of experimental finishing off of gas generaturs are briefly considered. This book is intended for engineers and designars in the area of rocket technology. Foreword Gas generators are widely used in rocket equipment. Their main units axe very similax to the ma,in units of basic rocket engines; however, the operating processes in gas generators have essential special features which must be taken into account in designing and finishing them off. Numerous patents and ma.gazine articles have appeaxed in recent yea,rs in connec- tion with rocket equipment, and the expanded use of gas generators, which resulted in investigations of gas generator devices [2]. Brief information on gas genera- tors is available in manuals on the bases for designing rocket engines [2, However, as a whole, published materials on gas generators are disconnected, frag- mentary and methodologically inhomogeneous. In this book the authors attempted to systematize the description of the axrange- ments and special features of the operating processes in gas generators using different fuels, based on the basic principlea of rocket engine theory. The book contains five chapters. Chapter one describes the basic chaxacteristics of gas generators and the fuel compositions used, and considers sepaxately the methods for laboratory and test stand teata. 1 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/42109: CIA-RDP82-00850R000500094407-0 FOR OFFICIAL USE ONLY Chapter two describes the special feattxes of gas flows in the gas generator, the gas conduit and exhaust nozzles, as well as methods for calculating the gas dynamic characteristics of gas generatora. Questions of filtering gas generation products and of gas thermodynamic processes in the devices axe elucida.ted. ohapter three reviews the special features of the devices on the basis of calcu- lating one and two-component liquid gas generators, as well as gas generators using fluidized (powdered) fuel. Chapter four considers design arrangements, methods*for internal ba.llistic cal- culations and vaxious possible methods for ragulating hard fuel gas generators (especially, by front combustion chaxges), including multiplo connection gas generators. The problem of transition processes during the change of decisive parameters is solved. The last chapter describes questions of developing vaxious combination gas genera- tors using solid (with sepaxate components), quasihybrid and hydxid fuels in steam- gas generators and gas generators of direct-flow rocket and rocket-tuxbine engines; engineering methods axe given for calculating the bas;c caaracteristics of a num- ber of gas generators. Chapters one, four and i'ive were written together; chapter txo by A. A. Shishkov and chapter three by B. V. Rumyantsev. The authors express their dQep gratitude to A. P. Tishin for his valua,ble recom- - mendations and for facilitE.ting the improvement of the manuscript in all its com- ponents; to candidate of techrlical sciences M. Ye. Yevgen'yev for useful advice in snlving problems in several sections. They will be grateful to readers who find it possible to send their comments to IzdateZ'stvo "Mashinostroyeniye" to addresso 107076, Moscow, Stromynskiy per. 4. COPYRIGHT: Izdatel'stvo "Mashinostroyeniye", 1981 2291 CSO: 1861/197 2 FOR OFFIC'IAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 FOR OFFICIAL USE ONLY NUCLEAR ENERGY UDC 621.039 CURRENT STATE AND OUTLdOK FOR HTGR RESEARCH IN USSR Moscow ATOMNO-VODORODNAYA ENERGETIKA I TERfIIdOLOGIYA in Russian No 2, 1979 (signed to press 8 Jun 79) pp 57-66 [Report TC-10913 at meeting of Technical Cammittee on HTGR's. IAEA, Vienna, 12-14 Dec 1977] [Text] An examination is made of the ma3or advantages of high-temperature gas-cooled thermal and fast reactors, along with the feasibility of using them for electric power pro- duction and generation of high-potential thermal energy. A survey is given of theoretical and experimental research on such reactors in the USSR. Initial Assumptions , Electric power production accounts for about 20% of the worldwide consumption ; of energy resources, while 80% of energy resources (petroleum, gas and coal) are expended for industrial and household heating purposes, transportation, in the chemical, metallurgical and otrer areas of industry. Among world reserves of fossil fuel, only coal is far from being exhausted (according to estinates, only 2-3X of the reserves will be used up by the end of the century). However, transportation problems and the high cost of electric power plants that use coal considerably reduce the competitiveness of coal as compared with petroleum and gas, which has led in recent decades to preferential use of these valuable chemical pxoducts for energy purposes, to their increased cost, and in future will lead to earlier depletion of their reserves as compared with coal. From this standpoint, nuclear power must cover the needs of electric energy production, and at the same time be used f.or producing process heat. An important factor favoring development of nuclear power is the ecological situation. Environmental pollution may become a serious limitation on the road to further expenditure of fossil fuel, and especially coal, for power production. Naturally, nuclear power must undergo technical changes far successful intro- duction in new fi.elds. District heating and production of low-potential heat 3 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102/49: CIA-RDP82-00850R440500090007-0 FOR OFFICIAL USE ONLY can be successfully handled by light-water reactors. On the other hand, metal- lurgy, the chemical industry and hydrogen production require the developm en t of reactors with temperature level of 800-1000�C and higher. At the present stage, high-temperature heliwn-cooled reactors (HTGR's) can be considered the most efficient sources for combined production of electrical and high- potential thermal energy. Giith extensive development of nuclear power, scales may be limited by nuclear fuel resources. The world reserves of inexpensive uranium commensurate in respect to energy resources with petroleum reserves will have already been exhausted by the beginning of the next century. The fuel problem can be solved by breeder reactors that by expanded conversion can extend the capabilities of uranium by dozens of times, putting into the cycle even the uranium dissolved in sea water. Considering the actual characteristics of energy consumption (i. e. the variable loading schedules, thE necessity of producing high-potential heat and so forth), it is neceseary to set up an economically feasible two- component nuclear power structure including thermal reactors (light-water reactors and high-temperature plutonitun and thoriinn reactors) and breeders with a short doubling time (4-6 years). Such a doubling time is easier to achieve by fast helium reactors that have good physical and technological characteristics. Helium breeders will be able to accumulate secondary plutonium for their own development, as well as nuclear fuel for thermal reactors which may comprise up to SOX in the nuclear power system. In this case, when involve- ment of thorium is considered, an outlook is opened up for development of nuclear power on a truly enormous scale (Fig. 1-3). N ao a.~ A ~ a$4i :1 > 7+ �1"~ bn J.J ~ co 41 ~ 41 O ~ a~ v w ~ o a 0 -4 a) ~v > u v t/~ d 1,0 0,9 0,8 0,7 p m ~ 44 Q) O �rl 1J Ol Ki ~ u Cd ~ a ~ 0o u ~ ~ o A a 1 0 100 150 100 150 Power production kWyr/hd Years Fig. l. Scales of development of _ power production (zones of undeter- mined use of energy resources are shaded) Fig. 2. Doubling time of nuclear power capabilities 4 FOR OFFICIAI, IISF ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 ~1~~~---1-- energy res. 0 10 20 50 !D 50 APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R000500090007-4 G 0 .,4 -W ~ ~ ~ U 'C ~ ~ X �rl ~ c~C aG F+ :J u .r4 w -H u v a fn FOR OFFICIAL USE ONLY Power production kWyr/head ~ a~ b a~ ~ O G O -H U cd w Fig. 3. Uranium consumption and necessary numbers of breeders Peculiarities and Advantages of HTGR's HTGR's have some distinguishing features and advantages that make them the most - promising for the nuclear power industry. Principal among these are: 1) high temperature, better thermal eff iciency, lower heat emissions to the environment, lower consumption of cooling water; 2) high safety due to high negative reactivity, high heat capacity of the graphite core, absence of phase transitions and chemica'L inertness of the coolant, and the presence of a number of safety barriers (microsphere fuel elements - el.ement cladding - prestressed concrete vessel - emergency enclosure of the nuclear electric plant); 3) efficient fuel cycle (including Th and Pu) due to excellent neutron-physics characteristics, high accumulation factor and breeding ratio of fuel; 4) reliability in operation, simplicity of servicing, lower specific activity of the loop and leakage of radioactivity to the environment; 5) capability of high-power instdllations with lower capital investment, use of a gas-turbine cycle, "dry" cooling towers, simultaneous production of elec- tric power and high-potential thermal energy, use of nuclear electric plant to cover peak loads. HTGR Research Areas Experimental facility with VGR-50 reactor of 50 MWe power. Purpose: accumulation of experience in designing and building HTGTc's, working out hetium technology, dynamics, safety, mass testing of fuel eler!2nts, test- ing components of reactor control system, equipment components, etc. The engineerir.g plan for the project has been worked up. 5 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 o 100 200 300 lvo APPROVED FOR RELEASE: 2007/02109: CIA-RDP82-00850R000500090007-0 FOR OF'FIC'IAL USF: ONLY 2. Prototype facilities: with VG-400 thermal reactor of 1000 MWt power for process energy purposes; with BGR-300 fast reactor of 300 MWe power. Purpose: accumulation of experience in making installations with HTGR's and FGR's, developing equipment (gas blowers, sceam generators, heat exchangers) studying problems of making prestressed concrete vessels, industrial methods of using high-potential thermal energy, confirmation of feasibility of attain- ing the required conversion properties in breeders. Design work has been done on the rough-draft and planning stage. Coordinated work is bPing done by scientific research and planning design agencies. 3. Industrial facilities with HTGR's and FGR's of more than three million kWt po w er. Purpose: production of high-potential heat, regener- ators, synthetic fuel, hydrogen for industry, transportation and household use; for purposes of electric power production with the use of a direct cycle, air cooling and utilization for covering peak loads. Studies are being done on parameters and prospects for using large HTGR's for the national economy. State of Research on HTGR's Theoretical and experimental research. 1. Studies are being done on analyzing areas for most efficient use of HTGR's: a) for electric power production (here other types of reactors may be com- petitors), including with gas-turbine facilities and for covering peak loads; b) to produce high-potential process heat (this field of application of HTGR's is most promising, including in connection with the lack of competition at the present time). Under consideration are the processes and sectors of in- dustry that consume t}ie most 'energy, and also utilization for transportation and domestic purposes: metallurgy, where the use of HTGR's will reduce demands for coke and natural gas, and when the technol.ogy has been successfully developed will enable tran- sition to the process of direct reduction of iron; chemical industry (production of ammonia, methanol, ete.); gasification of coal; }ieat supply to centralized consumers. Partictilar attention is being given to hydrogen production by dissociating water, since water is an unlimited source of the most ideal energy carrier, which can be used in the power industry, metallurgy, chemistry, households, transportation, etc. 6 FOR OFFICIAI. USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500094447-0 FOR OFFICIAL USE ONLY 2. Physicotechnical studies are being done on different HTGR designs (physics and thermophysics of reactors, dynamics, fuel cycles, various kinds of fuel elements, safety, etc.). 3. Materials for HTGR's are being studied. Research is in progress on dif- ferent kinds of graphite for fuel elements azd reflector, construction materi- als for equipment (tubing, steam generators, heat exchangers, etc.), insulation materials. 4. Work is under way on fuel element manufacturing technology (spherical and prismatic versions) and making microsphere fuel elements. 5. Research is being done on equipment components in facilities and nuclear - electric plants (prestressed concrete vessels, steam generators, heat exchan- gers, etc.). 6. Research is in progress on helium coolant technology, yield of fission products, monitoring instruments and helium cleaning system. 7. Facilities are being developed and made for studying patterns of movement of fuel elements, rods of the control system, materials and the like, critical stands (Astra, Grog) (Fig. 4), experimental helium loops (PG-100) (Fig. 5). R.eactor ampule tests are being done on fuel elements and microspheres. to sampling system 6,1000 m 3 -0.03 kg/ M2 220'r. 20' 25'C r'- ~ B00 e ?00 C M ~ t ~ 3800 ) yo,60'c ~ =10 kW A 0025~ r kg/cm 4. Astra critical stand 8. Research is being done on heliun-cooled fast reactors that have an advan- tage over other types of fast breeders in higher breeding gain and shorter doubling time; e-cperiments are being done on critical assemblies (Korba). P;anning and design work. 1. Development is in progress (engineering design stage) on a two-loop experimental chemical process facility with HTGR ~ (Fig. 6). 7 '2BO�c ?90'C j 11 "-to evacuatio:i =1.5k / 2 tem pp- o makeup 220�C 25'c system ~ + 120'C ` T 40= 60'C N=5 kW n=9000 rpm p=0.O1 ~~kg/cm~ FOR OFF[C1AL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R004500094007-0 Emergency Emer coo w 0 U Channel FOR' OFFICIAL USE ONLY Intermediate Fig. 5. Schematic diagram of PG-100 gas loop with channel for testing spherical fuel elements *expansion of 3IIIC not given Fig. 6. Diagram of nuclear chemical processing facility: 1--irradiator; 2--reactor; 3--steam generator; 4--turbo- generator Power--50 M"We Heli.um temperature--280/800�C Pressure--40 kg/cm Core dimensions--D/H = 2.8/4 m Control rods: in reflector and pylons--24 submerged--4-6 Fuel element--sphere = 60 mm) Number of fuel elements: in facility--260,000 in reactor--125,000 Fuel enrichment--21% Burnup--100,000 MW�day/metric ton Gamma power of radiation loop--300 kW 8 . FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102/49: CIA-RDP82-40850R040500094007-0 FOR OFFI('IAI. USE ahLY Ne = 300 MW; tin= 300'C; T2 = 6.5(8.0) yr; t~iX= 800�C; Tcn= 0.5 (1.0) yr max tfuel � 2150% ' Fuel U02 + Pu02 p_: 20o kg/cm 1)..-180kg/cm li, I(7,7; yr - 6.3(7,6) yr N� - 25 MW np eHT3 = 0,7 5.9 (7,3) yr t `'Nf'iK-' M\I ~KOi1f-O aKO;u=2 Mn~ 6,0 (7.4) yr 5.2 (6,3) yr ( _ AH,.3-0,7 M AH ,-0.5 6 4 (7-7)yr I T . Pu compo- bK~m=~ sition RgM (WER+RBMK) ' 5.6 (6.8) yr r 4,5 5MG yr ~ I I I ~ eHT,-o,7 M eRr,3=o 7 M t_ AR6,-.0,4 N, 6, 1 (7.4) yr ~ Ne = 300 MW; dKOX = 0; T2 = 3.5(4.3) yr; AHT3 = 0.7 m; Tnep= 0.5(1.0) yr; AR= 0.6 m; p= 200 kg/cm2; tin= 300�C tout = 620�C; t~iX = 800�C; Nnp3 = 25 MW; tfuel m 2150�C; Fuel U02 + Pu02 Fig. 7. Influence of BGR-300 parameters on fuel doubling time Steam parameters--90 atm, 535�C Reactor shell--steel Number of cooling loops--4 Proposed completion deadline--1985 9 FOR OFFICIAL USE ONLY - p. - Ir,o kg/cm t 620" C out =f50' C F.4 (7,8) yr Na,r -2> MW A~~'p' --:IS MW 6,1 (7.61 yr Ana.14 =3.81C$/Cm APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2047102109: CIA-RDP82-00850R400504090047-0 FOR OFFICIAL USE ONLY 0 0 M Fig. 8. Fast breeder reactor with helium cooling (integrated version): 1--passage for extracting and installing cassettes; 2--passage for reloading mechanism; 3--gate; 4--prestressed concrete vessel; 5--reloading mechanism; 6--steam generator; 7--breeding blanket; 8--core; 9--gas blawer; 10--control system drive; 11--rotating device; 12--truck with telescopic . hcisting crane 2. Development is in progress (rough-draft stage) on prototype facilities (different versiotis) for producing process heat (up to 950�C) with power of 500-1000 MWt with HTGR using spherical and block fuel elements, including the VG-400 technological power unit: - 10 ~ FOR OFFIC[AL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 1 2 ~ - APPROVED FOR RELEASE: 2007102/09: CIA-RDP82-00850R000500090007-4 FOR OFF'ICIAI, l1SE ONLY M-_rmal power of reactor--1000-1100 MW ?lelium te:nperature--350/950�C Helium pressure--50 kg/cm2 Core dimensions--D;H = 6.4/4/8 m Control rods in reflector and core Fuel element--sphere (0= 60 mm) Number of fuel elements--800,000 Fuel enrici=ent--10% Run--3-4 yr Nunber of loops--4 Electric energy production--300-400 MW Hydrogen production (thermochemistry, methane conversion)--(20-25) 103 nm3/hr per loop Vessel--prestressed concrete Proposed deadline--1985-1990 3. Development is in progress (rough-draft stage) on a demonstration fast helium reactor with power of 300 MWe (Fig. 7, 8): Thermal power--800 MW Helium temperature at reactor outlet-- 600-850�C Helium pressure--160 kg/cm2 Energy release rate--500 kW/liter Fuel--U02-Pu02 Breeding ratio--1.6-1.7 Doubling time--6-8 yr Second loop parameters--170 atm, 540�C Vessel--prestressed concrete Nuclear electric plant efficiency--38% Deadline undetermined 4. Studies are being done on parameters of facilities proposed for industrial introduction after 1990. COPYRIGHT: Institut atomnoy energii im. I. V. Kurchatova, 1977 Atomizdat, 1979 6610 CSO: 8144/1052-A 11 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500094447-0 FpR OFFICIAL USE ONLY UDC 621.039 SOME REQUIREMENTS FOR NUCLEAR-CHEMICAL FACILITIES WITH HIGH-TEMPERATURE REACTORS Moscow ATOMNO-VODORODNAYA ENERGETIKA I TEKHNOLOGIYA in Russian No 2, 1979 (signed to press 8 Jun 79) pp 67-72 7 [Article by N. D. Zaichko, I. Ya. Yemel'yanov, A. M. Alekseyev, V. M. Panchenkov, Yu. I. Koryakin, A. A. Orlov, E. K. Nazarov, V. A Chernyayev, S. A. Mikhaylova, L. P. Dudakov and S. V. Radchenko] [Text] The authors consider conditions of forming power- process arrangements for prodi;r.ing hydrogen, amonia and other goods based on direct conversion of heat from high- temperature nuclear reactors to a technological process. Based on these conditions, major requirements are formulated for high-temperature reactors to serve industrial technology: service life, time between repairs, radiation safety, etc. Ref. 1 reported on the feasibility and major areas of introducing high-tempera- ture reactors for making hydrogen, ammonia and other products. It was shown that the process most ready for realization in respect to.receiving thermal energy from high-temperature reactors is steam catalytic conversion of hydro- carbons. Therefore let us consider some requirements for nuclear-technological facilities that realize conversion processes. As fossil fuel is displaced by nuclear fuel, there is a considerable reduction of labor inputs, an increase in labor pr.oductivity, and a reduction in produc- tion outlays and settling expenditures per unit of final product due to a reduction of labor inputs on extracting and transporting fuel because of the _ much higher "calorific value" of nuclear fuel over any kind of fossil fuel. Nonetheless, along with the overall reduction in the level of labor expendi- tures in the national economy, there may be some increase i.n the nitrogen industry. Therefore careful analysis and detailed examination of this point must be taken into consideration when studying the feasibility of introducing nuclear reactors into industrial technology. When high-temperature heat is produced by burning natural gas, an arrangement with better technical-economic efficiency is two-stage endothermic conversion of inethane, which is mainly the basis for ammonia production (Fig. 1). 12 FOR OFFICIAL USF. ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 FOR OFFI('IAI. USF. ONLY 1 2 ~ i ~ ' - SC e - ~ ~u -a-rt------e-~-a-, --_-t-_~--~-~_ I c t~ean ing ~ ---j I I Y 3 etha onv onv ~atiMEA -1'~ . , Fig. 1. Classical ammonia production scheme: 1--natural gas turbocompressor; 2--air turbocompressor; 3--nitrogen-air mix- ture turbocompressor; 0 process gases; air; natural gas (fuel); o-- feed water; water vapor Engineering, design and economic workups of plans for the first nuclear-chemical complexes are based on ammonia and methanol production aggregates with capacity of 2500-3000 metric tons per day. The choice uf this ammonia and methanol pro- duction capacity has dictated a required power of the nuclear reactor instal- lation of 550-600 MWt. With r.espect to conditions of direct utilization of high-temperature heat = from nuclear reactors in amanonia production, an arrangement with two-stage methane conversion is most preferable, although it is possible to realize a scheme with single-stage conversion of inethane and additional displacement of fossil fuel even in the process channel. The advantages of the two-stage . arrangement are as follows: maximiun capabilitias for replacing fuel gas with nuclear fuel; minimum level of working temper.ature of the stage of the technological process in whi,h heat from the liigh-temperature nuclear reactor is to be used--less than 875�C; the natural gas consumed in this arrangement is divided into two flows: fuel ~ (45-50%) burned to get high-temperature heat, and process gas, facilitating cc>nditions of replacing the fuel natural gas with nuclear fuel; steam catalytic endothermic conversion of inethane is accomplished in individual tubular reactors with diameter of less than 150 mm with external supply of high-temperature heat through a solid wall (rather than in an integrated work- ing volume), which is more favorable for direct utilization of heat from high- temperature nuclear reactors; the tubular reactors used in present-day production have a guaranteed service life of 100,000 hours, retain gas-tightness at a temperature of up to 950�C 13 F'OR OFFIC[AL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102/09: CIA-RDP82-00850R000500090007-4 FOR OFFICIAL USE ONLY ? 900-(1154=1500)'C BSQ'C 900-(1150T1300) 'C 950'CyonveYSion conversiA\,~He or sol 0- (orsol products ' oolant) Pr~ducts ' Q,d coolan 0 30D f1CQ7=1100J'C SOO1C 500'C 6 y BD0 -(1100=1100J CH4*H20 3501C a CH4 +N20 9A0-(I150=1,i00J�C 850 ~ 2 conversion c ~e (or soli products ~ coolant) 3 Fig. 2. Versions of utilizing 0 .~oo-~icna�r2oo1' S50'C 7 6 5 4 nuclear re:.;tor in ammonia pro- ~ 350�C duction: 1--reactor; 2--coolant CN4+NZG loop; 3--converter; 4--heater for b steam-gas mixture; 5--steam super- heater; 6--steam generator; 7-- water heater Structure of heat utilization (Gcal/hr) in energy scheme of ammonia production facility with capacity of 3000- metric tons per day Index Conversion of steam-gas mixture Heating steam-gas mixture Steam generation Steam superheating Heating feed water Heating steam-air mixture Heating gas mixture Heating fuel gas Total power from heat source Thermal power of reactor not counting internal needs, MWt With use of Without nuclear reactors using nuclear only for for conversion and reactors conversion generating steam (initial at pressure of 110 atm version) Version 1 Version 2 Version 3 185.0 26.4 68.0 185.0 26. 68.0 185.0 26.4 68.0 185.0 26.4 238.5 113.1 113.1 113.1 - 57.4 57. 57. - 12.0 12.0 12.0 12.0 10.6 10.6 10.6 10.6 0.2 0.2 - - 472.7 472.7 472.5 472.5 - 215.0 525 525 N ote: Above the broken line the heat is supplied by the nuclear reactor; below by burning natural gas and pressure of 30-40 atm, and may serve as an engineering base for making new tubular conversion reactors that take heat from the nuclear reactor coolant; a considerable part of the produced hydrogen (theoretically up to SOy) is formed from water rather than from methane (CHq+ 2H20= C02+ 02), which means . 14 FOR OFF1C(AL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00854R000500090007-0 FOR OF'FICIAI. USE ONLv that steam catalytic conversion of methane based on nuclear reactors can be considered as a first step on the road to producing hydrogen from water. The possible versions of using nuclear reactors, distribution of the thernnal power of the reactor with respect to consumers in ammonia production based on two-stage catalytic conversion of inethane, and the principal values of technolog'Lcal parameters and working media are giver. in Fig. 2 and the table. Version 1(see Fig. 2a) assumes utilization of heat from nuclear reactors only in the high-temperatuce part of production--in the first stage of methane conversion for heating reaction tubes. Heating of the steam-gas mixture, the steam-air mixture, feed water, gas mix- ture, superheating of steam and generation of saturated steam in an auxiliary boiler are accomplished in this case by heating nacural gas. All equipment remains unchanged other than the heat-utilizing fAcility, which is slightly modified. Starting conditions and transient processes are unaltered. The advantages of this version are: relative simplicity of construction of the reactor unit that heats only one flow the steam-gas :aixture in the con- version process, and most complete retention of the basic technc.logical equip- ment for ammonia production (excepting the tubular furnace). Its disadvantage is the small fraction (about 20%) of liberated natural gFs from the total production requirement, and low reactor power. Version 2(see Fig. 2b) almost totally obviates the use of natural gas as a fuel. In this connection, the heat necessary for steam conversion of nethane, heating the steam-gas mixture, feed water, and also for generating and super- heating steam with pressure up to 110 atm is provided by a high-temperature reactor. Version 3(see Fig. 2c) is distinguished by the fact that the reactor facility is used only for steam conversion of inethane, heating the steam-gas mixture and producing saturated steam at pressure up to 110 atm. In view of the com- paratively small required total thermal power (500-600 MW), high-temperature heat and energetic steam can be produced by a single reactor even for long- range process arrangements. In practice, the area of a single chemical combine accommodates several production facilities (ammonia, methanol, higher alco- hols, etc.) with various technological chains in each one, and from arguments of economy and standby capabilities it is advisable to arrange parallel con- nections between the individual technological chains within each facility and among facilities. This may make it possible to centralize production of hydrogen-containing gas mixtures and energetic steam in separate specialized reactor facilities. The advantages of this arrangement are operating reliability of each technologi- cal chain with lower expenditures on standby equipment and greater economy and reliability of producing high-temperature heat and energetic steam on specialized nuclear reactors. Successful solution of the problem of hydrogenating large amounts of carbon monoxide into methane with liberation of considerable amounts of heat may in 15 FOR OFFIC[AL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R000500090007-0 FOR OFFICIAL USE ONLY future enable rational solution of problems of distributing the high-temperature nuclear reactors over the area of the chemical,enterprise. Existing and newly planned facilities in.the nitrogen industry must meet the following require- ments i prolonged accident-free operatioti over the.established work life (up to 30 years); high level of utilization of installed power of process equipment (up to 8000 hr/yr); high reliability of all machines and equipment incorporated in the techno- logical chain; ease of control, high degree of automation; high level of labor productivity, maximum output from each worker; minimum necessary consumption of raw materials and energy resources; transportability, producibility and repairability of all equipment; high economy of operation of entire facility. Direct utilization of the heat of high-temperature nuclear reactors in the energy-consuming industrial processes of ammonia and methanol production also involves solution of some technological problems, chief among which are: developing and producing reliable accident-free reactors with coolant tem- perature of 900-1400�C at the core outlet and total working life of up to 30 years with yearly r.ontinuous-duty operation of up to 8000 hours; development of reliable and efficient technical facilities for heat transfer from the reactor core to the working volume of process equipment; working out engineering measures to ensure protection of final goods and tech- nical equipment from radioactive contamination; .,olution of the problem of diffusion both from the core into the process chan- , nel and in tte reverse direction. Even ncw when operating facilities for amnonia production with a capacity of 1360 metric tons per day, considerable difficulties arise in th~l matter of training operating personnel with appropriate skills. The introduction of nuclear-chemical complexes requires implementation of additional steps in this direction, since the working conditions for service personnel in the process nart of the facility will evidently be on a par with those of nuclear elec*iic plants; requirements will change with respect to the makeup by specialties and the training of service personnel. 16 FOR OFFICIAL USE ON1.Y APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500094447-0 FOR OFFiC1AL USF ON1.Y Conclusions 1. The current state and engineering prediction of development of high-tempera- ture reactor equipment and nuclear fuel technology, the start that has been made on research and development, and analysis of the outlook for making a nuclear-chemical f acility for ammonia and methanol production based on methane conversion allow us to count on organizing an experimental industrial plant of this type in the next 10-15 years. 2. The major prob lems in making and using hi gh- temperature nuclear reactors in industrial processes of inethane conversion are in the area of transferring ~ the high-temperature heat from the core to the working volume for carrying out the technological process with appropriate observance of conditions of protecting products, service personnel and the enviroment from radiation at the required level of rr_liability and redundancy of the nuclear power source. REFERENCE 1. Dollezhal', N. A., in: "Voprosy atomnoy nauki i tekhniki. Seriya: Atomno-vodorodnaya energetika" [Ptoblems of Nuclear Science and Engi- neering: Series on Atomic Hydrogen Power], Preprint No 2, I. V. Kurchatov Nuclear Power Institute [IAE im. I. V. Kurchatova], 1977, p 5. COPYRIGHT: Institut atomnoy energii im. I. V. Kurchatova, 1977 Atomizdat, 1979 6610 CSO: 8144/1052-A 17 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R000500090007-4 ~ "a hOR OEFICIAL USE ONLY UDC 621.039 PARTICULARS OF LAYOUT AND CONSTRUCTION OF EXPERIMENTAL INDUSTRIAL HIGH- TIIMPERATURE GAS-COOI.ED REACTOR MODEL Moscow ATOMNO-VODORODNAYA ENERGETIKA I TEKHNOLOGIYA in Russian No 2, 1979 (signed to press 8 Jun 79) pp 73-77 [Article by F. M. Mitenkov, Yu. N. Koshkin, U. B. Samoylov and Ye. V. Komarov] [Text] An examination is made of the layout and construc- tion features of the reactor, and also the problems to be solved on an experimental industrial facility. The proposed plan allows development of the facility by stages with dif- ferent temperature levels. High-temperature helium-cooled reactors are a new field in nuclear power. Their distinguishing feature is the feasibility in principle of getting heat with a high temperature up to 1000�C or more. Such a temperature potential cannot be attained in other power reactors currently known. Possible ways of utilizing high-potential heat have been extensively studied in the USSR and elsewhere. Research shows that raising the temperature of the heat generated in a reactor to 750-800�C enables utilization of modern turbines with high steam parameters (ts = 530-580�C). It is evidently inad- visab le to further increase the temperature for a steam-turbine cycle. There is a much better outlook for using the HTGR in a gas-turbine cycle, and also as a source of thermal energy for technological processes in various sectors of the national economy in which 70-80% of all generated energy is consumed as heat, particularly in the most energy-intensive processes of the chemical and metallurgical industry. Analysis has shown that to replace fossil fuel with nuclear fuel in these processes the coolant temperature must be 950�C or more. Such a temperature is attainable in the HTGR, opening up ex- tensive possibilities for using the reactor in this field. The use of high-temperature heliwn-cooled reactors in a high-energy process facility for producing thermal energy is looked upon as the major area for reactor utilization. Design developments have revealed that combined production of electric power and high-potential heat is most advisable from the econrnaic :ztandpoint, enabling effective uCilization of generated heat with fairly high e:rficiency. 18 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102/09: CIA-RDP82-00850R000500490007-4  FOR OFFICIAL USF. ONI.Y Development of commercial reactor installations for combined production of high-potential thermal energy and electric power necessitates a large voliune of scientif ic research and experimental design work, enabling resolution of some engineering proUlems relating to the production, conveyance and utilization of heat with very high temperature, assimilating heliwn technology, working out new kinds of equipment and new materials. Considering the complexity of the problem, it seems necessary to make an ex- perimental industrial reactor installation. The purpose of such a facility is to check and confirm all major engineering decisions, and to develop the principal equipment and control systems under conditions of industrial oper- ation. The development of an experimental industrial facility will open up the way for producing commercial models of the facility and using them on a wide scale. In order that experience in developing, making and using the model might sub- sequently to the maximum extent become a basis for making commercial instal- lations, it is necessary first of a11 to make a correct and sound choice of the direction of p].anning and the initial technical parameters, i. e. to work out the optimum technical requirements for an experimental industrial model of the high-temperature reactor with consideration of its ultimate purpose. The technical requirements for an experimental industrial model stem from the jobs it is to handle: 1) checking and working out the layout of the facility, including the process loop; 2) checking designs of the principal kinds of equipment and systems, and re- fining them from operational results, when such units are clearly to a great extent unique (gas blower, steam generator, drives in the reactor control system, heat exchanger, cleaning system, monitoring system, etc.); 3) operational. check of structural components and technology of reinforced concrete vessel; 4) checking new heat-resistant structural materials under conditions of pro- longed operation, atc. The necessity for prelimirary solution of the enumerated problems precludes the use of a low-power facility for this purpose. A reactor with thermal power of 1000 MW can be recommended for the experimental industrial facility. In this case the ma3or components of the installation (core, steam generators, gas blowers, heat exchangers) will have been prototyped on a sufficient scale fur future commercia] facilities. Wtien working up the design of an experimental industrial facility, considerable attention must be given to optimizing the layout of the facility with cunsider- ation of ensuring potential capabilities of getting information when developing new commercial energy-intensive technological complexes. As an experimental industrial model we can consider a facility intended for generating high-temperature heat that would be utilized for producing electric 19 FOR OFFICiAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/42109: CIA-RDP82-00850R000500090007-4 FOR OFFICIAL IiSE ONLY encrgy in a nuclear puwer plant. Realization of such a project would enable us to work out principal solutions of the plan layout, as well as the equipment in the facility, including the reinforced concrete vessel, to incorporate into operation the fundamentally new loop with helium coolant, and to elaborate the working conditions of the facility. In this case it would be much easier to solve the probleTn of choosing structural materials since steam parameters (ts = 530-550�1~) can be ensured at a temperature of 750�C in the first circuit. However, this.version would lack capabilities for checking the plan of the technological complex using high-potential heat and developing equipment at a temperature necessary for the commercial technological complex. ;Che second way is to develop a direct prototype of the energy complex in full scale, and hence with working temperature needed for supporting the given process cycle (t= 950�C). This assumes development of new heat-resistant materials, thereby pushing back the real deadline for making the experimental industrial facility. Furthermore, it should be taken into consideration that startup and alignment on this facility will undoubtedly take a long time, and bringing the temperature up to working level will be gradual. Most of the time on startup and alignment is taken up by the reactor installation proper since it is the most complex and important part. However, the disadvantages of the second version can in large measure Ue elimi- nated if the design of the experimental industrial model allows development of the prototype by stages. For this purpose, the facility diagrammed in Fig. 1 can be suggested as an experimental industrial model of the installa- tion. The heat produced in the energy unit can be used to generate electric power in a turbogenerator, and also for producing hydrogen in a chemical process coiplex. i5 ~ I Fig. 1. Schematic diagram of experimental industrial nuclear power-producing and pro- cess facility (NPPF): 1--reactor; 2--high- temperature intermediate heat exchanger; 3-- steam generator; 4--main gas blower; 5--chemi- cal process circuit; 6--intermediate circuit; 9 7--gas blower for intermediate circuit; 8-- turbine; 9--generator; 10--condenser; 11-- condensate pump; 12--low-pressure water heater; 13--deaerator; 14--feed pump; 15--high-pressure water heater Recilization of the chemical technological process of hydrogen production re- qtiires a first-loop coolant temperature of 900-950�C at the reactor outlet. High-p:irameter steam is generated in the steam generator at temperature of 750�C at the inlet to the first loop. Such a facility can be manuf actured and developed in three stages. On the first stage the facility can be worked out on a temperature level up to 750�C with generation of electric energy in a steam-turbine cycle (Fig. 2) 20 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 900'950�C APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R000500090007-0 FOR OFFICIAL USE ONLY Fig. 2. Sc'nematic diagram of NPPF for first and second stages of operation: 1--reactor; 2--high-temperature inter- 7 mediate heat exchanger loop; 3--steam generator; 4--main gas blower; 5--bypass; 6--turbine; 7--generator; 8--condenser; 9--condensate pump; 10--low-pressure water heater; 11--deaerator; 12--feed pump; 13--high-pressure water heater without completing development and manufacture of the heat exchanger, devel- oping high-temperature fuel or installing the equipment of the chemical complex, by installing bypass pipes in place of the heat exchanger. Maximum reactor power in this mode is 70% of Wnom� The flowrate of coolant in the first loop, and all paramsters of the steam generator and gas blower will be nomina"l. On the second stage, with the same makeup of equipment as on the first, the temperature at the outlet of the core can be raised to 950�C, the former tem- perature level being maintained in the steam generators by diluting the hot coolant coming from the core with cool gas fed from the pressure side of the gas blower through bypass 5(see Fig. 2). On the third stage after making and installing the intermediate heat exchanger and all chemical process equipment, as well as completing startup and alignment work on the reactor facility, the entire facility shown in Fig. I can be de- veloped and brought up to nominal power. The plan for an installation with combined production of haat and electric energy is the most optimtnn solution in choosing an experimental industrial model of a facility with high-temperature helium reactor using thermal neutrons. This model provides an excellent prototype for the most promising power- producing and process f acilities, and the design of the equipment and layout of the instllation allow the necessary multistage manufacture and operation of the model. COPYRIGHT: Institut atomnoy energii im. I. V. Kurchatova, 1977 Atomizdat, 1979 6610 CSO: 8144/1.052-A 21 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 9UG=950 750 C APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R000500090007-0 FUk OFF1C'IAL USF ONI.Y UDC 621.039 CHOOSING DESIGN CONCEPT AND PHYSICAL FEATURES OF HTGR CORE FOR ENERGY FACILITIES Moscow ATOMNO-VODORODNAYA ENERGETIKA I TEKHNOLOGIYA in Russian No 2, 1979 (signed ti press $ Jun 79) pp 78-84 [Article by G. P. Goroshkin, A. S. Kaminskiy, V. D. Kolganov, Ye. M. Kuz'min, M. D. Segal' and V. P. Smetannikov] [Text] The authors consider the design of a high-temperature channel reactor with spherical fuel elements with thermal power of 540 MW with helium temperature of 950�C at the outlet of the core. Physical and hydraulic profiling of the core reduces the maximtun temperature of the fuel elements. , The advantages of such a reactor over other designs are indicated for use as part of a power-producing facility _ with combined supply of energy to chemical, metallurgical and other energy-intensive facilities. Ttao directions of development of HTGR's are known in world practice: with a stationary core and with moving fuel elements in the core. The first direction is characterized by the use of large graphite blocks in the form of hexagonal prisms in the core (reactors of the HTR type) with ninner- - ous openings for accommodating the fuel and passage of the cooling gas. This ' type of core is stationary, and recharging requires.the use of loading machines that operate relatively rarely when replacing individual depleted blocks of the core or replacing the core in its entirety. In the second direction, the core consists of a chargE of spherical fuel ele- ments that contain both fuel and moderator. In a reactor with such a core (type AVR and THTR) fresh elements are loaded and depleted elements are unloaded continuously during operation at power for a prolonged period. In our view, disadvantages of such directions in reactor construction are: a) for the first type of reactor: shutdown of the reactor during reloading of core blocks; variation of energy release distributions during reactor oper- ation; comparatively long time for reloading core; high labor-intensiveness and technological complexity of fabricating the graphite core blocks; consid- erable thermal sCresses that arise in graphite blocks under high heat loads; 22 , F'OR OF'FICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 FOR OFFI('IAL (1SF. ONLY 2 1- 4 5. b Fig. 1. Agat reactor facility: 1--loading macl-iine; 2-- intermediate heat exchanger; 3--actuating mechanism of reac- tor control system; 4--prestressed concrete reactor vessel; 5--convers?on furnace; 6--core b) fcr the second type of reactor: nonuniformity of spherical fuel element movement in the core; no capability for precise profiling af energy release with respect to core radius; necessity for accommodating the rods of the reac- tor control system in the charge of spherical fuel elements in the core in graphite pylons specially provided in the body o� the core; possible fluctua- tions of porosity in the charge of spherical fuel elements of the core over the entire period of reactor operation; graphite moderator in the fuel ele- ments, leading to additional expenditures when reprocessing depleted elements. For industrial facilities (e. g. chemical, metallurgical and other sectors of the national economy), uninterrupted operation of the reactor throughout the technological production cycle is of decisive importance. This condition is met to a greater extent by reactors with continuous fuel recharging during oPeration at Power. Reactors with spherical fuel el.ements can be put into this category. The Agat reactor (Fig. 1), designed tu produce high-potential. licat fur the needs of chemical production, represents the first attempt to develop a facility that would not have the disadvantages of the above-mentioned reactors while retaining their positive features. The following design features have been incorporated into the facil.ity: channel type core; regular geometry of core channels and control rods; partial separation of moderator and fuel; use of principle of one-time passage of fuel elements through the core; con- tinuous reloading of spherical elements during reactor operation at power; clpability for rearranging physic3l channels. 23 F'OR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00854R000500090007-0 FOR UFFI('IAL USE ONLY The core of the Agat reactor is made up of graphite componerits with the excep- tion of the upper spacing plate and the lowPr support plate. The fuel ele- ments are r.iicrospheres in a graphite matrix enclosed in a graphite cladding of spherical Shape 60 mm in diameter. The moc+erator of the core is a set of vertically arranged prisms in which the fuel elements move (Fig. 2). The prisms are.held in the lower support plate by metal sleeves that are hinged to the plate. Concomitant movement of fuel elements and coolant is neces- sary to maximize the' coolant temperature at the outlet from the reactor at the permissible temperature in the center of the fuel element with the highest heat release rate (for example ~ we can have a coolant temperature of 1200�C at the reactor outlet when the temperature ~ inside the fuel element is 1300-1350�C). The core is surrounded by a graphite reflector made of hexagonal prisms. Above it is an Fig. 2. Core fragment upper heat shield made of graphite blocks. The upper face of the core is conical; this is necessary so that the depleted fuel elements can roll down past the boun- daries of the core. The thickness of the side reflector in the radial direc- tion averages 1200 mm, and that of the upper reflector in the axial direction averages 1000 mm. The reactor control system consists of 61 rods; these move in the same channels as the fuel elements and have a working section with absorber 5 m long. The drive mechanisms are situated on the cover of the reactor vessel. Ttie equipment is configured in the following way. The prestressed reactor vessel is a monolithic block with recesses'to accom- modate the major equipment of the facility, emergency a�tercooling equipment, and the channels of the reactor circuit (see Fig. 1). In the central part of the vessel is a cylindrical space for accommodating the core, reflectors, heat insulation of the vessel and lower support plate for the core. Above the central cavity is a passage to accommodate the reactor cover. In the lower part of the vessel under the core are seven vertical passages for in- stalling the loading mechanisms for the spherical fuel elements. To accom- modate the gas blowers af the reactor loop and the emergency aftercooling system, horizontal passages are provided in the reactor vessel in which the blowers are placed toget}ier with their drives. A hermetically sealed carbon steel facing (liner) fills the inside of the reactar vessel. To ensure the necessary temperature conditions for operation of the vessel, the liner is protected by heat insulation with a gas layer a so-called gas wall and tubes of a water-cooling system are buried in the concrete of the vessel at a certain distance from the liner. The cylindrical cavity of the housing is divided into two sections by the lower support plate, which has a passage for the fuel elements under each channel of the core, and openings for passage of the coolant that serves the moderator and reflector. A device for feeding fresh fuel elements into the channel is placed in each channel opening of the plate. 24 ;IcinL USE oNLti. APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102/09: CIA-RDP82-00850R000500090007-0 FOR OFFIC'IAL USE ONI.Y Seven reloading mechanisms provide continuous reloading of fuel elements during reactor operation. The spherical elements are loaded into each channel, each serving its own part of the core. When one of these mechanisms fails, the reactor is capable of operation at somewhat reduced power (about 15% below nominal) right up to shutdown for routine maintenance. The design with lower placement of reloading mechanisms is chosen for the fotlowing reasons: the supporting structures of the core are situated in the zone of "cool" coolant; operation of the reloading mechanisms is facili- tated by the absence of control rods under the core; the force from the pres- sure differential in the core is directed opposite to the force of gravity of the fuel elements and side reflector; coolant circulation in the reactor circuit coincides with the direction of motion of the coolant with natural circulation in the reactor in case the gas blowers stop; the principle of one-time passaqe of fuel elements through the core requires concomitant move- ment of fuel elements and coolant. The propased design has typical physical features of the HTGR, among which we note the following: 1) use of graphite, a weak absorber of neutrons, as the moderator, which ensures neutron economy, improves the breeding proper- ties of the core and reduces the charge of uranium compared with other types of thermal reactors; 2) bur.nup is much higher than in other reactors: about 105 MW�days per metric ton; 3) the negative temperature coefficient of reac- tivity and large heat capacity of the core ensure a high degree of safety. At the same time, the proposed design successfully combines the advantages anci avoids the disadvantages of the spherical and prismatic forms of HTGR fuel elements. Regularity of the passage of fuel elements through the core in the proposed ch:innel reactor enables the use of a var.iety of effective methods of profiling the field of energy release. The necessary profiling through the core body can be achieved by: varying the fuel. enrichment with 235U in profiling zones; c.hanging the rate of passage of the fuel elements in profiling zones; varying the density of the graphite moderator. Temperature fields in the core body can also be equalized by hydraulic pro- filing. II, kW - - ~ 20 - - - 15 L 0 50 100 150 200 250 R, cM Fig. 3. Channel power distribution with respect to core radius ln the proposed reactor, three-zone profiling of the core is provided by using two types of fuel elements differing wi.th respect to 235U enrichment and moving 25 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500094447-0 FOR OFF'1('IAL l1SE ONI.Y at different velocities. Enrichment of fuel elements in the central (I) and peripheral (III) zones is 6.5%, and in the intermediate zone (II) 10%. This reduces the coe�ficient of nonuniformity of channel power along the radius of the reactor to 1.05 (Fig. 3). The proposed design extends capabilitiss for controlling the process of bring- ing the core up to steady-state operation. This is done by providing ccntrol- lable placement of absorbing elements specially introduced into the channels, and corresponding configuration of the control rods. The proposed channel reactor design facilitates physical monitoring of core parameters at the necessary nunber of points to get reliable information, enabling on-the-spot correction of the coeff icient of nonuniformity of energy release, raising the specific and thermal load on the fuel, and increasing the average burnup. The configuration of the control rods in the channels can also be optimized, which raises their effectiveness. In this way, the design has advantages over the AVR, where the control rods are situated around the periphery of the core in individual pylons. f, .C 1250 1200 t c 1150 1100 QK' [f050 rel s 0,95 950 0,90 900 pgg 850 0 Q 0,5 1,0 1,5 2,0 2,5 R,A: Fig. 4. Distribution of rela- tive heat release Qk, gas tem- perature t~ and temperature in the center of the fuel core tc along reactor radius R _Z NK 0,8 0,7~ 0,6 0,5 0,4 0,3 0,2 0,1 Fig. 5. Distribution of rela- tive heat release QZ, gas tem- perature tg, cladding temperature tcl and temperature in the center of the fuel core tc over the height of the core Z /Hk Proy;rammed motion of the fuel elements in each channel assumes stable dis- tribution of energy release heightwise of the core throughout a run, and con- comitant motion of fuel elements and coolant maximizes the gas temperature at the core outlet at the permissible fuel temperature. Thermohydrauiic cal- culations for steady-state operation iiave shown that the temperature distri- bution can be kept fairly uniform through the core body (Fig. 4, 5): Stiidies have shown that nonuniformity of the coefficient of heat transfer over the surface of a sphere {rom maximum to minimum is 2.2-3.0, and as a result, heightwise the maximur.i fuel temperature may be 10�C higher. 26 FOR OF FICIAI, l'SE: ONI.ti' APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 G 200 400 600 800 10001200 f,0C 015 1,0 1,5 2,0 2,5 3,0 Qz APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 FOR OFFICIAL t1SE ONI.Y The feasibilitv of hydraulic profiling was checked for the selected version of physical profiling to determine the effectiveness of equalizing temperature fields along the radius of the core. For a channel diameter of 74 mm in physi- cal profiling zone II and 75 nnn in the other zones, the gas temperature at the outlet from the channel cores can be equalized and maximwn fuel temperature can be reduced by 20�C compared wi.th the hydraulically unprofiled version. When the channe.l_ diameter is 72 mm in physical profiling zone II, a reduction in maximu~.n fuel temperature by 50�C is achieved, but nonuniformity of gas temperature at the core outlet is increased to 130�C as compared with the 110�C nonuniformity for the unprofiled version. Of course, hydraulic profiling somewhat increases the hydraulic drag of the core: for the unprofiled version, hydraulic drag is 0.39 kgf/cm2; with channel diameter of 74 mm, drag is 0.41 kgf/cm2, and for 72 mm 0.45 kgf/cm2. , Based on thermohydraulic calculation, we can conclude that physical profiling enables attainment of the necessary equalization of temperature fields, while hydraulic profiling in the given case is less effective and requires at least two sizes of channels in the core. As a result of design analysis, neutron-physics and thermohydraulic calcula- tions of the reactor, the following characteristics are obtained: Thermal power of reactor, MW 538 Dimensions of core, m: 6 diameter 5 height Number of channels 3481 Fuel element diameter, mm 60 ChargP of uranium, kg 6570 Enrichment, 6 5 in profiling zones I and III . in profiling zone II 10 Run, days: for fuel elements of profiling zones I and III 860 for fuel elements of profiling zone II 800 Reactor coolant heliian Coolant flowrate in reactor circuit, kg/s 160 Coolant temperature, �C: at inlet to reactor 306 at outler from reactor 950 Coolant pressure in reactor circuit, kgf/cm2 40 In summary, we can conclude that engineering and design cal.culations have dem- onstrated the feasibility of developing a high-temperature gas-cooled reactor combining the advantages of cores of channel and microsphere types. Such a reactor can be used to produce high-potential heat in the chemical, metal- lurgical and other energy-intensive sectors of the national economy. COPYRIGHT: Institut atomnoy energii im. I. V. Kurchatova, 1977 Atomizdat, 1979 6610 CSO: 8144/1052-A 27 FOR OFFICIAL USE ONL.Y APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 FOR OFFICIAL l1SF nNI.Y UDC 621.039 MOLTEN-SALT REACTOR WITH NATURAL CONVECTION OF FUEL MIXTURE AND OPEN GAS- TURBINE AIR CYCLE Moscow ATOMNO-VODORODNAYA ENERGETIKA I TEKHNOLOGIYA in Russian No 2, 1979 (signed to press 8 Jun 79) pp 85-93 [Article by V. A. Legasov, I. G. Belousov, N. K. Yerokhin and A. S. Doronin] [Text] The authors consider some problems of using a high- temperature molten-salt reactor with natural convection of the fuel mixture in the primary circuit. Radiation pro- vides the thermal coupling between the primary circuit and the energy (or process) circuit. Reactor heat can be used at a temperature near maximum. Combining a reactor of this type with a gas-turbine facility operating on an open cycle gives efficient conversion of heat to electricity. N,tclear reactors with molten salt fuel mixture are in many respects an instruc- tive phenomenon in nuclear power. lnterest i.L these reactors arose in tiie 1950's in the United States in connection with development of a nuclear air- craft [Ref. 1]. An experimental reactor with pawer of 8 MW (MSRE) [Ref. 2] was operated at Oak Ridge National Laboratory from 1966 to the spring of 1968. During this period, 70,000 MWh of electricity was generated, and extensive experimental material was acctuuulated on many aspects of scientific and design developments of molten-salt reactors, which was the basis of project MSBR a one-fluid breeder reactor with thermal power of 2250 MW [Ref. 3, 41. Project MSBR was shelved, although the anticipated properties of a nuclear power plant of this type opened up unique prospects both from the standpoint of utilizing (Ref. 51 and reprocessing [Ref. 6, 71 nuclear fuel, and from the standpoint of capital expenditures [Ref. 41. There was no more really serious work on the problem of the molten-salt reactor, and poorly advised attempts to revive interest in the idea have led to considerable discreditation. There are two reasons why it was quite natural to stop work on pro,ject MSBR. First of all, the power industry was not yet feeling any scarcity of nuclear fuel, ar.d with the comparatively low fuel component in the cost of nuclear electricity, extra efforts to develop technology for processing salt fuel seem economically superfluous even in an ideal fuel cycle like that of the MSBR. In the second place, the coolant temperature attained in the primary 28 FOR OFFICIAL USE ONI.Y APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102/49: CIA-RDP82-00850R440500090007-0 FOR OFFICIAL l1SF ONLY circuit (700�C) is lower than in the HTGR, and further upward movement on the temperature scale is impeded by the particulars of interaction of salt with structural materials based on metals. On the other hand, the low capital component of the MSBR is obtained by calculation and cannot be taken as a conclusive argument. The situation is considerably altered if inetal-based structural materials are eliminated from the molten-salt energy circuit. An isothermal high- temperature molten-salt reactor design (VTRS) has been proposed in which the only metallic structural materials in the salt circuit are in the pump group. The purpose of our research is to examine the peculiarities of a VTRS in which the only structural matarial in contact with the molten-salt fuel mixture is isotropic pyrolytically precipitated graphite. The thermophysical layout of a power plant with such a reactor is exceptionally simple, and the attainable level of the coolant temperature in the primary loop, and also the thermodynamic quality [Ref. 81 of the reactor may be anomalously high. Heat from the core is transferred to a radiant heat exchanger by natural convection of the fuel mix- ture in graphite coaxial fuel elements. The resultant efficiency of a nuclear power plant with VTRS may reach 50-60%, and the thermodynamic quality of the reactor may be 0.95-0.98. Thus the way is opened up for considerable improvement. of high-temperature nuclear heat sources for future pawer 3nd process applications. ~ ~ I . I I ~ A temperature difference between the inner and outer colwnns of liquid (Fig. 1) is obtained by external heat removal in a radiant heat exchanger from the upper part of the fuel element, and volumetric nu- clear heating of the lower part. Pararaeters of flow of the molten salt in the circuit of the fuel element are: Gr - (gd2 l.pl10) 0_%l, �Dl(D + d) - 10" = 1010; Re = p::,d; Et - 5- 103 5- 10'; Nu = ad,'}. - 50 100; St = Nu/(f',e�Pr) - 10-3 = 10-2, where Gr, Re, Nu, St are the Grashof, Reynolds, nusselt and Stanton n,unbers. Conventional symbols are used to denote the parameters. The law of cir- culation is approximately described by the dime:- sionless equation [Ref. 9] I D-d 3 D-}-d 1�75 Gr = 2,5Re~ I 4 > ( d > ~ Fig. 1. Design of co- axial fuel element with natural convection of salt fuel mixture (LiF --0.75, ThF4--0.24, UF4 --0.01) D- d D= - d= Reo.2s ~2) L+ I c1= )21 0,316 ' We can see from equations (1) and (2) that a chanoe in temperature head Atl by a factor of nearly 100 is possible between the salt and the outer wal.l of 29 FOR OFFICIAL USE ONI.Y APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02109: CIA-RDP82-00850R000500090007-0 FOR OFFICIAL USE ONLY the graphite channel in the vicinity of the radiative heat exchanger without changing the turbulent flow state (Blasius interval). In other words, at a fixed average temperature of the salt fuel mixture the external load can be reduced by two orders of magnitude while maintaining stable circulation. , 6 ~ 3 ~o ro 2 0~ B00 1000 /ZAD 1fQ0 T, K 1 0 10 20 30 H, kcal/mole Fig. 3. Example of process consumption of heat from the nuclear reactor (conversion of coal to carbon monoxide) - t, . C ~ f000I 5,00 a~lp 100 ar, ~oe 0,5 47 1a Fig. 2. Typical diagram of temperature distribution in the salt circuit, the outer jacket of a fuel element, the heat exchanger tubes and air heated therein to 64Ne kP - exP~ R j* 28,2) _ 0 10 "LU JU 9U Pv uv /mole Fig. 4. t-H diagram of heat consumption on the first stage of a two-stage water thermolysis cycle The nuclear reactor is made up of a series of fuel elements. The temperature differential lengthwise of the fuel element cladding (Fig. 2) in the zone of 30 FOR OFFICIAL USE ONLY ,'C - a. ~p p kp - exp ~ R . f*2~ 100 arm 10 i 2INe 000 10 10 la a5 d 1 S00 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R000500090007-0 FOR OFFI('IAL USF ONI.Y heat removal is about 100-150�C. Consequently, all high-temperature reactor heat can be transferred to the heat exchanger at a temperature little differer.Lt from uaximun. This explains the high thermodynamic quality of the VTRS as a heat source. Fig. 3 and 4 show examples of possible process consumption of nuclear heat of comparatively high quality. For example, when coal is converted to carbon monoxide (Fig. 3) according to the Boudoir reaction 2C0 2Ht0 2COt } 4H:; 1 (4) AGz 9,55 + 1,9 T1300 kcal/mold with subsequent exothermal generation of carbon dioxide COt C � 2C0; ( AG, = 41,3 - 12, 6 T1300kca1/mo1~_ (3) It can be seen that carrying out reaction (3) at pressure of 10 atm involves compensation of the reaction energy in the temperature range of 750-1050�C. Fig. 4 shows the t-H diagram of heat consumption in the temperature range of 820-1000�C associated with the first stage of the two-stage cycle of water thermolysis: 1: 2M11rO:, . 11n -MII_% ; ?(.n. 1 L; ;1C., . 65,5 - 22.1 T/300kca1/mo14 LsO; ll: Mn.,% 2C0_ ; 2,%WC0., I- 1,20.; ~1G4 8, I-- 12,6 T/300kca1/mole ) ~G~ Obviously hig:i-efficiency thermolysis cycles can be realized only in the case where an external heat source is capable of compensating the reaction energy in a narrow range of temperatures close to maximimm. An example of a cycle of water dissociation with low-quality heat from the source is the sulfuric acid cycle: i: ii:sol so, + }izo; 11: SO3 SOs + i/2Oz; 111: 2Hz0 + SOs FI'SO4 -f-'i= 11 0 25 50 75 ,H,. kcal/mole Fig. 5. t-H diagram of'heat consumption on two stages of sulfuric acid dissociation: I--S03-S02+;102i II--H2SO4-* S03 + H20 31 FOR OFFICIAL USE ONLY (7) APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500094447-0 FOR OFFI('IAL USE ONLY The t-H diagram of the first two stages is shown on Fig. 5. The reaction energy is compensated in a temperature range of 370-900�C, and in this case we cannot count on high energy efficiency of the cycle corresponding to the maximum temperature of the heat source. It is known [Ref. 10] that the limit-, ing thermodynamZc efficiency of a cycle of dissociation of a substance inCo components does not depend on the use of either exceptionally high-temperature heat or electricity obtained from the Carnot-cycle machine. The limiting efficiency of the dissociation cycle,is uniquely determined by the nature of the substance being decomposed and the extremum temperatures of the heat source and drain. In this sense the process utilization of high-temperature nuclear heat in the thermolysis cycle does not automatically give any advan- tages over the traditional method of generating electric energy and subsequent electrolysis (or plasma-chemical reaction [Ref. 11]). High-productivity elec- trolyzers or plasma-chemical reactors combined with a good electric power plant may be preferable to thermolysis process facilities. Therefore the method described below for converting high-temperature and high-quality nu- clear heat to electricity by using a gas-turbine installation with open air cycle may be taken as a component in development of one of the important ele- ments of process utilization of nuclear energy. I -----1 r 6 ~ti=-50�C 0, g8atm I P� ~ ~ 0,5~576 atm ; 0,4 0,7 0,8 0,9 bz 0 S a b --`l- ~A-7 _2 5/ 3 y c Fig. 6. Simple thermodynamic cyzle (b) of gas turbine power plant with open air cycle (rlt = i.95; nc = 0. 9; e= 0.8; tg = 1273 K; SI:- n 8;); dependence of efficiency on total hydrau- r=i lic losses in the air channel and air temperature at the compressor inlet (a) and schematic diagram of realization of this cycle based on VTRS heat (c): . 1--reactor; 2--heat exchanger; 3--turbine; 4--regenerator; 5--compressor A comparison of temperature curves for salt coolant and air in a radiative heat exchanger (Fig. 2) shows the possibility of a further appreciable increase in efficiency of utilizing high-temperature heat of the VTRS. However, some open gas-turbine cycles even on the given stage of optimization enable us to get quite high characteristics (Fig. 6). The air temperature at the inlet to the turbine is taken as 1000�C. The degree of regeneration of 0.8 is near optimum; the total relative hydraulic losses through the channel 1- dE are equal to -0.14. The resultant efficiency of the power plant is 0.44 for air 32 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 FOR OFFICIAL USE ONLY temperature of +20�C at the inlet to the compressor, and 0.53 for air tempera- ture of -50�C. We should also take note of the low maximum pressure in the air circuit for temperatures of +20 and -50�C: about 6 and 8 atm respectively. This factor is quite significant for getting a reliable design of a high- temperature radiant heat exchanger. It is proposed that grade KhN45Yu steel be used as the construction material. The wall thickness of the hot tubes of the heat exchanger is 3 mm. At a temperature of 1100�C and pressure dif- ferential of 1 atm, the long-term (10,000 hr) strength reserve is 2. T Tg p=6,5-18,5at TK-540K 4 T in ' 0,5 0,6 0,7 0,8 0,9 8r 0 S a b ~ tin`'50�C 0,6 p=13,4 atm , 0,5 p~9,45 94 tin20�C n; J c Fig. 7. Characteristics of open gas turbine cycle with one intermediate heater (conditions and notation same as on Fig. 6) More complicated cycles enable us to improve the efficiency of the power plant (Fig. 7). The schematic of the power plant is a little more complex, but there is an appreciable gain in eff iciency. For example at ambient air temperatures of +20 and -50�C the efficiency of a gas-turbine unit with two- stage heating is 0.48 and 0.56 respectively. The next step in improving the '1 - 07 ' tins-50�C p=23 atm\ 0,6 patm 0,5 0,4 1-1 0,5 0,6 r P=17: 27 atr T=\0 0,7 0,8 0,9 6F a b 6 c ? Fig. 8. Characteristics of open gas turbine cycle with intermediate cooling of air in the compressor (conditions and symbols the same as on Fig. 6; b--intermediate cooler) cycle involves adding an intermediate stage of air cooling in the compressor (Fig. 8). The efficiency of the facility increases to 0.52 and 0.60 for air temperature at the inlet ri the gas turbine unit of +20 and -50�C respectively. Optimum pressure in the air channel is 18.5 and 23 atm. Fig. 9 shows a clear comparison of efficiency of complex gas-turbine cycl.es for different air tem- peratures at the inlet to the compressor. As these data imply, it makes prac- tical sense to develop complex cycles although pressure increase is a con- straint. 33 FOR OFF'ICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102/09: CIA-RDP82-00850R000500090007-4 FOR OFFICIAL USE ONLY p-23at p=11,y atm 1,6 3 9,5 3 1 p1,98at 7~4 2 j , ~3 - ' ~ p-1gfat p=Batm r ~ ~ p=576. a ' 0,5 0,6 0,7 0,8 0,9 6Z 45 0)6 47 0,8 0,9 6Z a b c Fig. 9. Comparison of efficiency of complex gas-turbine cycles at different air temperatures at the inlet to the compressor: a--nt = 0.95; nc= 0.9; e= 0.8; titl=-50�C; Tg = 1273 K; b--nt = 0. 95; nc= 0. 9; E= 0. 8; tin = 20�C; Tg = 1273 K We must emphasize a number of f.actors that are organically related to direct process utilization of VTRS's, or to their use in combination with a gas tur- bine power plant. 1. The attainable level of working temperatures of structural components based on graphite-salt opens up wide vistas for conquest of the h3gh-tempera- ture region. 2. The use of natural circulation of the fuel mixture in the primary circuit - obviates the need for developing a high-temperature pwnp group, and enables transition to nuclear sources of high-temperature, high-quality heat. 3. The fuel cycle of molten-salt reactor systems is among the most promising both from the standpoint of complete utilization of fissionable materials (uranium, thorium, plutonium) in accordance with the sequence u_ 1 and from the standpoint of reprocessing and disposal of fission products. 4. Absence of a water-cooling energy cycle makes nuclear power plants of the proposed type independent of a source of cooling water and more ecological compared with conventional plants. 5. Thc attainable efficiencies in the VTRS give access to new possibilities in technology of converting heat to electricity. 6. The fact that industry is prepared to produce air gas-turbine plants of the required class gives important economic advantages to development of 34 FOR OFF[CIAL 1JSE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 FOR OFFICIAL USE ONLY high-temperature nuclear pawer in the direction of the VTRS. Research orgzni- zations, design offices, metallurgists and machine builders have accumulated adequate experience for f ormulating and solving the problem of making gas- turbine power plants of the required class. REFERENCES 1. Bettis, E. S., NUCL. SCI. ENGNG, Vol 2, No 6, 1957, pp 804-825. 2. Haubenreich, P. N., Engel, I. R., NUCL. APPL. TECHN., Vol 18, 1970, p 118. 3. Tosenthal, M. W., Kasten, P. R., Briggs, R. B., NUCL. APPL. TECHN., Vol 8, 1970, p 170. 4. Bettis, E. S., Robertson, R. C., NUCL. APPL. TECHN., Vol 8, 1970, p 190. 5. Engel, I. R., Kerr, H. T., Allen, E. I., TRANS. ANS., No 22, 1975, pp 705-706 6. Grimes, W. R., NUCL. APPL. TECHN., Vol 8, No 2, 1970, pp 137-153. 7. Kashcheyev, I. N., Zolotarev, A. B., "Pirokhimicheskiye metody regeneratsii metallicheskogo i solevogo yadernogo topliva (obzor patentov i nauchno-tekhnicheskoy literatury 1956-1972 gg.)" [Pyrochemical Methods of Regenerating Metallic and Salt Nuclear Fuel (Survey of Patents and Scientific-Technical Literature for 1956-1972)], Moscow, Gosudarstvennoye ob"yedinennoye nauchno-tekhnicheskoye izdatel'stvo, 1973. 8. Belousov, I. G., in: "Voprosy atomnoy nauki i tekhniki. Seriya: Atomno- vodorodnaya energetika" [Problems of Nuclear Science and Engineering: Series on Atomic Hydrogen Power Engineering], Preprint, I. V. Kurchatov Institute-of Nuclear Power [IAE imeni I. V. Kurchatova], No 2, 1977, p 152. 9. Belousov, I. G., "Th.rmal Physics of Fuel Elements With Natural Circulation of Molten-Salt Fue' ',xture" in: "Voprosy ato�,nnoy nauki i tekhniki. Seriya: Atomno-vodorodnaya entrgetika", Preprint, I. V. Kurchatov Institute of Nuclear Power [IAE imeni I. V. KurchatovaJ, No 1(4), 1973, p 201. 10. Belousov, I. G., in: "Voprosy atomnoy nauki i tekhniki. Seriya: Atomno- vodorodnaya energetika", Preprint, I. V. Kurchatov Institute of Nuclear Power [IAE imeni I. V. Kurchatova], No 1, 1976, p 65. 11. Belousov, I. G., Legasov, V. A., Rusanov, V. D., in: "Voprosy atomnoy nauki i tekhniki. Seriya: Atomno-vodorodnaya energetika", Preprint, I. V. Kurchatov Institute uf Nuclear Power [IAE imeni I. V. Kurchatova], No 2, 1977, p 158. COPYRIGHT: Institut atomnoy energii im. I. V. Kurchatova, 1977 Atomizdat, 1979 6610 CSO: 8144/10; 2-A 35 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02/49: CIA-RDP82-00850R440500090007-0 FOR OFFICIAL USF ONLY UDC 621.039 PHYSICAL FEATURES OF HTGR WITH CIRCULATING FUEL Moscow ATOMNO-VODORODNAYA ENERGETIKA I TEKHNOLOGIYA in Russian No 2, 1979 (signed to press 8 Jun 79) pp 94-100 [Article by N. N. Ponomarev-Stepnoy, A. Grebennik, V. Ye. Demin, V. S. Malkov, Tsurikov and L. A. BogatovaJ N. Protsenko, Ye. S. Glushkov, V. N. L. K. Malkova, 0. N. Smirnov, D. F. [Text] An investigation is made of the characteristics of a high-temperature gas-cooled thernal reactor with graphite moderator for combined utilization of high-temperature heat and gamma radiation of spherical fuel elements circulating in the system made up of the reactor and irradiator. A curve is given for the way that the power of gamana radiation of the irradiator depends on the multiplicity of fuel circu- lation in the system. An examination is made of the particu- lars of fuel burnup effects compensated by absorbing elements that circulate concomitantly in che system made up of the reactor and irradiator. The main tendency in the deve.lopment of nuclear power at the present time is expansion of limits of application not only in electric power production, but also for producing high-temperature heat, energy supply to the metallurgi- cal industry and production of reducing agents for metallurgy, power and heat supply to many sectors of the chemical industry, stimulation of chemical pro- cesses, etc. [Ref. 1-31. Research has shown [Ref. 3] that these problems can best be solved by using high-temperature reactors with helium coolant. In particular there is a certain interest in the use of a nuclear reactor as a source of radiation for radiation-chemical processes. In this connection, use is made of gamma radiation of fissuion products in the radiation circuits as fuel is circulated in the reactor-irradiator system [Ref. 5, 6]. A diagram of fuel circulation is shown on Fig. 1. The reactor is the high- temperature VGR-50 with graphite moderator, helium coolant and spherical graph- ite fuel elements based on microspheres with multilayer coating [Ref. 41. The reactor permits combined use of high-temperature tieat that is removed by the helium coolant from the packed spherical fuel elements, and transportation to the irradiator of gamma-emitting fisGiun products in the makeup of the irradiated fuel elements due to their circulation. It is desirable that the 36 F'OR OFFICIAL USF: ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02109: CIA-RDP82-00850R000500090007-0 FOR OFF[CIAL USE ONLY I Fig. 1. Diagram of fuel cir- culation in facility with com- bined use of energy and gamma radiation: 1--reactor; 2-- irradiator time of delivery of the irradiated fuel and its stay in the irradiator be short (a few hours) so as to use the radiation of short-lived isotopes of fission products. Fig. 2. Diagram of nuclear reactor: 1--core (packing of spherical fuel elements and absorbers); 2--gap; 3--top end reflector (graphite); 4--control rods; 5--radial reflector (graphite); 6--bottom end reflector (graphite); 7--pylons (graphite pro3ections) for control rods A physical diagram of the nuclear reactor is shown in F'ig. 2. The radial graphite reflector forms a cylindrical cavity that tapers into a cone in the . lower part. In the bottom end reflector is an opening for unloading the con- tents of the core. The reactor is covered by the top end graphite reflector. The inner cavity is filled with spherical fuel elements and absorbers. Pro- visions are made for changing the ntnnber of absorbers in the circuit during circulation to compensate for fuel burnup during a run, the amount of ab- sorbers not exceeding 15% of the amount of fuel elements. Between the top end reflector and the spherical packing of the core is a gap that can be varied over a wide range during reactor operation. The nominal size of the gap is about 0.5 m. The main parameters of the reactor are'as follows: Reactor pozaer, MW 140 Coolant helium Helium pressure, atm 40 Helium temperature, input/output,�C 270/800 Core dimensions, D/H, cm 280/450 Spherical fuel element diameter, mm 60 Content of U in one fuel. element, g 2-5 Fuel enrichment, % 10-30 Power of gamma radia- tion in irradiator, kW 400 To study the influence that multiplicity of fuel circulation has on the power of gamma radiation in the irradiator, an analysis was made of experimental data on power and the spectral makeup of fission products [Ref. 7-10]. As a result of the analysis, an approximation formula is recommended for the time dependence of power of gamma radiation of fission products after fission: I'(t) = 1.5t-1'2+ 3.4t-1'4 MeV/(s�fission), 37 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 ' 2 3 4 APPROVED FOR RELEASE: 2007102/09: CIA-RDP82-00850R000500090007-0 ~ FOR UFFICIAL USE ONLY where t> 103 s. The change in spectral makeup of gamma radiation is illus- trated by the data of Table 1[Ref. 10] TABLE 1 Spectral makeup of gamma radiation of 235U fission products at different times after �ission, relative units - E nerpv ranQe, MeV Time after fission, s - o,i-o,s I o,s-i,o I i-z 1 :-3 I a-a 1 a-s 900 0,125 0,266 0,381 0,172 0,040 0,016 7,2�10.1 0,088 0,345 0,372 0,169 0,018 0,008 1,8�103 0,070 0,342 0,407 0,160 0,014 0,007 3,6�10' 0,103 0,376 0,410 0,098 0,008 0,007 8,6�10' 0,196 0,515 0,259 0,018 0,005 0,007 2,6�105 0,249 0,523 0,203 0,015 0,005 0,008 Theoretical studies h tion of an irradiator Pi P' P ve shown strong dependence of the power of gamma radia- on multiplicity of circulation in the system. Fig. 3 shows the way that the power of gamma radia- tion in the irradiator depends on the multi- plicity of fuel circulation. It can be seen that an increase in the muitiplicity of fuel circulation can raise the power of gamma radiation by a f actor of approximately 10 as compared with the case without fuel circu- lation. A further increase in the power of gamma radiation is limited by the hold of the fuel following the irradiator that is necessary for de-excitation of delayed neutrons (tdel = 10-20 min). The high core temperature leads to a strong temperature effect of reactivity. The change in effective Fig. 3. Dependence of power breeding ratio as temperature increases is of gamma radiation in the due to a ninnber of factors: irradiator on multiplicity of fuel circulation (P Doppler broadening of resonant levels of power of gamma radiation; 238U as fuel temperature is increased; Pp--reactor power; N--mul- tiplicity of circulation (run a change in the spectrinn of low-energy neu- of 1-2 years) trons, whic:i leads to a reduction in the yield of secondary neutrons per absorption in the fuel, a change in the ratio of absorption of the neutrons in the fuel and in other elements of the reactor, and an increase in the square of the diffusion path of thermal neutrons; the temperature change in the density of reactor materials and the dimensions of its components, which primarily affects neutron leakage. Tahen studying reactor dynamics, it is important to break down the temperature effect of the reactor into individual components, which we took as follows: 38 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 V 1 10 100 1000 N APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R000500090007-0 FOR OFFI('IAI. USE ONLY the temperature effect of the fuel; this is the fastest-acting effect and is due mainly to Dopper broadening of resonant levels of 238U; temperature effect of the moderator associated with effects of thermalization of slow neutrons, change in density of the moderator in the core and change - of dimensions; temperature effect of the reflector associated with the change in the spectrum of low-energy neutrons and the dimensions and density of the reflector. ek Fig. 4. Components of reactor temperature effect: 1--reflec- tor effect; 2--fuel effect; 3-- moderator effect dk ~ 'k - 0,07 ~ - 0 10 20 CN?" kg/m3 Fig. 5. Influence that water in the core has on reactivity (CH2o is the amount of water per m3 of the core with submerged (1) and extracted (2) compensating control rods) The overall temperature effect is negative (Fig. 4), and the reduction in the eff.ective breeding ratio as temperature increases may reach -10Y. Fluctuation of the level of sphere stacking in the core influences reactivity as a result of change in core height and the shooting effect in the cavity between the top end reflector and the core. Dependence of reactivity on the relative width of the gap between the top end reflector and the core stacking (Fig. S) near the nominal stacking level has a rather flat slope, which is due to the large height of the core compared with its diameter. As the reactor operates, certain changes in the density of spherical packing can be observed. In this connection, an estimate was made of the effect that a change in the porosity of spherical packing of the core has on the effective breeding ratio; this effect is characterized by the quantity dk/de= -0.33. The high por.osity of the core makes such a reactor quite sensitive to hydrogen- containing substances in the core (water, water vapor, etc.). The following factors may influence the breeding ratio: an increase in the moderating power of the core, leading to an increase in the probability of avoiding resonant absorption of neutrons by 23BU (positive effect) ; a reduction in the length of migration of neutrons in the reactor, leading to a reduction cf neutron leakage from the reactor (positive effect); Absorption of neutrons in hydrogen (negative effect). A typical maximum can be observed on the curve for reactivity as a function of the content of water (water vapor) in the core (Fig. 6). 39 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 FOR OFFICIAL USE ONLY _ Fig. 6. Reactivity as a function of gap between top end reflector and spherical stacking of the core (d--gap; HQ--distance between top and bottom end reflectors) M Ma 0 2 0,5 Fig. 7. Number of absorbers in core to compensate burnup effects: 1--units with burna- ble absorber 10B; 2--units with unburnable absorber; M--number To compensate for effects of burnup of absorbers located in the core with rapid circulation of fuel in the stacking; t/TK--ratio of elapsed reactor, special absorbers of spherical time to run time shape (like the fuel elements) are added to the fuel charge of the core. As the reactor operates with circulating fuel, provision is made for the capability of changing the nwnber of absorbers in the spherical packing to maintain criticality. Fig. 7 shows the change in the necesfiary number of absorbers during a reactor run for two cases for burnable absorber (based on 10B) and for nonburnable absorber. The use of a"burnable" absorber, which does not necessitate a change in the number of absorbers during a run increases the negarive temperature effect of the moderator due to blocking of the absorber as temperature is increased. Fast circulation of fuel in the reactor determines the particulars of 135Xe poisoning due to entrainment of the irradiated fuel from the reactor with a large flux of thermal neutrons to the irradiator, where the thermal neutron flux is near zero with multiple repetition of the process. A peculiarity of 135Xe poisoning of the reactor during fuel circulation can be discovered by solving the following system of equations: aPi/01 -I rJIiI/Jz - Q)TSfTu'I - x iPi: r7p~e/df t~dp~c!Jz iDtE fill''X, + 7�~('~ ~~~~�~'S~� - ~Prl'~r^X~�~ where P1=pI(t, z); PXe - PXe(tl z) are the concentrations of 135I and 135Xe at time t at point z of the circuit; it is convenient to take as coordinate z the distance from the upper level of the core to the given point of the circuit in the direction of fuel movement; ')T(t, z) is thermal neutron flux density, EJT(t, z) is the macroscopic thermal-neutron fission cross section of the core, ai,Xge are the constants of radioactive decay of 135I and 135Xe; WI, Wge are the yields of the corresponding products upon fission of 235U; 40 FOR OFFICIAL IJSF: ONI,Y APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 FOR OFFIC'IAL USE ONLY Px. 0,04 tqs4,y h s~ e a 0,02 8. 0 45 r/N Fig. 8. Distribution of 13sXe con- centration heightwise of reactor with circulating fuel for differ- ent circulation times: where pXe, Ps are concentrations, QcXe, acs are the microscopic ther- mal-enutron absorptior, cross sections for 135 Xe and 235U respectively aXe is the macroscopic thermal-neutron absorption cross section of 135Xe; v is the velocity of fuel displacement during circulation. 4 ~ 1 Fig. 9. Distribution of heat release heightwise of the core: 1a--considering (16--disregarding) nonuniformity of temperature dis- tribution heightwise of the core in the presence of fuel circulation (Tu = 4.4 hr); 2--using the principle of one-time passage of fuel elements through the core At any time t, the solution of the system of equations should be periodic with respect to z with period ZK equal to the length of the fuel circulation loap. Let us note that ir.stead of z we can introduce the variable . : T dz'/v, rK where t,, dz'/v is the time taken by the fuel to complete one cycle. In the case where the time of circulation is close to the period of decay of 13sXe, strong nonuniformity is observed in the distribution of xenon con- certr.ation heightwise of the core (Ref. 8)y however, there is little change in the average xenon cWncentration. It is clear fron the distribution of heat release heightwise of the core (Fig. 9) that wY.en fuel is circulated the distribution of heat release is not very nonuniform (curves 1a and 16), whereas with one-time passage of fuel through the core in the equilibrium state one observes strong distortion of the distribution of heat release heightwise of the core toward an increase at the beginning of the zone (curve 2), which is cond+icive to equalizing the temperature of the core material. REFERENCES 1. Aleksandrov, A. P., ATOMNAYA ENERGIYA, Vol 25, No 5, 1968, p 356. 2. Aleksandrov, A. P., Ponomarev-Stepnoy, N. N., "Nuclear Power and Technical Progress" in: "Atomnaya energetika XX let." [Nuclear Power of the Twen- tieth Century], Moscow, Atomizdat, 1974. 41 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 0 0,5 z/H APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00854R000500090007-0 MOR OFFI('IAL USE ONLY 3. AlekSandrov, A. P. et al., "Bystryye i teplovyye geliyevyye reaktory dlya proizvodstva elektroenergii i vysokotemperaturnogo tepla" [Fast and Thermal Helium Reactors for Producirig Electric Energy and High-Temperature Heat], IAEA, Vienna, 1976, Vol 1. 4. "Sostoyaniye i perspektivy razvftiya rabot po VTGR v SSSR" [Current State and Outlook for HTGR Research in USSR], report TC-109/3 at meeting of Technical Committee on HTGR's, IAEA, Vienna, 12-14 December, 1977. 5. Ryabukhin, Yu. S., Breger, A. Kh., ATOMNAYA ENERGIYA, Vol 7, No 2, 1959, p 129. 6. Breger, A. Kh. et al., "Osnovy radiatsionno-khimicheskogo apparatostroyeniya" [Principles of Radiation-Chemical Equipment Making], Moscow, Atomizdat, 1967. 7. Way, K., Wigner, E., PHY;;. REV., Vol 73, 1948, p 1318. 8. Mayenshteyn, F., et al., "Gamma Rays Associated With Fission" in: "Trudy Vtoroy mezhdunarodnoy konferentsii po mirnomu ispol'zovaniyu atomnoy energii. T. 2. Izbrannyye daklady inostrannykh uchenykh" [Proceedings of Secand International Conference on the Peaceful Use of Nuclear Power. Vol 2. Selected Papers of Foreign Scientists], Moscow, Gosatomizdat, 1959. 9. Sakharov, V. N., Malofeyev, A. I., ATOMNAYA ENERGIYA, Vol 3, No 10, 1957, p 334. 10. Bunney, L. R., Sam, D., NUCL. SCI. ENGNG, Vol 39, 1970, p 81. 11. Dosta, L., De Tourrecil, R., J. NUCL. ENERGY, Vol 26, 1972, p 431. 12. James, M. F., J. NUCL. ENERGY, Vol 23, 1969, p 517. COPYRIGAT: Institut atomnoy energii im. I. V. Kurchatova, 1977 Atomizdat, 1979 6610 CSO: 8144/1052-A 42 FOR OFFIC'IAI. OSF: ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 FOR OFMI('IA1. l!SE ONI.Y UDC 621.039 SOME PROBLEMS OF HEAT EXCHANGE AND HYDRODYNAMICS IN HTGR CORE COMPONENTS (SURVEY) - Moscuw ATOMNO-VODORODNAYA ENERGETIKA I TEKHNOLOGIYA in Russian No 2, 1979 (signed to press 8 Jun 79) pp 142-148 [Article by Yu. N. Kuznetsov and V. L. Lel'chuk] [Text] The ?aper gives some r.esults of theoretical and experiment:l studies of heat exchange anc: hydrodynamics in the amLu]ar channels, rod bundles, and in channels with permeable walls as applied to helium-cooled high-temperature reactors. An examination is made of inethods of calculating thermohy- draulic processes in the primary circuit of HTGR's and GCFFc's. Mathematical Modeling of Processes of Convective Heat Exchange in Rod Bundles and Annular Channels. One of the authors (Kuznetsov) has been doing theo- retical research on convective heat exchange in HTGR cores with rod fuel ele- ments, in which the peculiarities are associated with comparatively low heat transfer coefficient, complicated geometry of the channel, variability of thermophysical properties of the coolant and large volinnetric flowrate. A theoretical study has been done on patterns of convective heat exchange in rod bundles and annular channels for arbitrary laws of change in the thermal load lengthwise of the channel. Yu. N. Kuznetsov has developed a technique that enables reconstruction of local values of heat exchange characteristics in any channel cross sections and for any law of heat supply based on studying Clie stabil.ized heat exchange far from the inlet with some specially selected law of heat supply. First for annual channels under conditions of constant thermophysical properties of the coolant and constant change in the heat load oi both surfaces lengthwise of the channel (with constant heat load on the perimeter), the author examined the principles of stabilizing heat exchange with increasing disatance from the channel inlet, introducing a criter-ion that characterizes the influence of heat load variability, and is proportional to the logarithmic derivative of the function describing the change in heat load lengthwise of the channel. As the heat load described by functions of exponential type changes with in- creasing length, the temperarure field of the coolant is stabilized, but 43 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00854R000500090007-0 F()R OF'M'1('IA1. l1tiE ONI.Y differs from the temperature field on the section of the heat exchanger sta- bi?ized with respect to length for the case of a constant load. These differ- ences increase with increasing relative rate of change in the load, and they characterizP the thermal inertia of tne flow. This enables us to reconstruct the influenre function for the given heat ex.�.hange process, which also charac- terizes the thermal inertia of the coolant flow. Mathematically, the process of finding the influence function reduces to solving an ordinary differential equation with unit boundary conditions in the complex plane, and to subsequent determination of some irtegral of the real part of the solution. The major difficulties arise in description of the velocity field and transport coefficients of the turbulent flow of coolant. A model of turbulent coolant flow in annular channels is proposed. Results of calculations of the charac- teristics of turbulent flaws and heat exchange by this model are compared with experimental data of various authors. Values and generalizing formulas for the ir..fluence function G1 are obtained for the temperature diEference between wall. and coolant over a wide range of working parameters and geometric dimensi.ons. It is shown that the problem of local heat exchar.ge characteristics in the case of longitudinal flow around infinite bundles of rods that are not too close can be reduced to investigation of heat exchange in the inner zone (between the rod surface and the line of maximum velocity) of such an annular channel for which the line of maximum velocity in some sense coincides with the line of maximum velocity of the given rod bundle. This has enabled us to u.se the above uescribed results for studying annular channels, giving relations for the influence function with heat exchange in rod bundles. The resultant formulas can be used for fair;ly exact calculations of local characteristics of heat exchange in any channel cross section with any law of variation in heat load lengthwise over a wide range of geometric and flow parameters : for annular channel 0< rl /r2 5 1; 104 < Re < 106 ; 0. 7 5 Pr < 100; for triangular or sqare bundle arrays 1.5 1 mm 35--Fraction kap ensuring the required equaliza- tion of fuel channel pawer and predetermined effective neutron multiplication factor ke01 1(without considering the action of the reactor control rods). In large channel reactors, (kaP - 1) is 2-5 times greater than (knc- 1) [Ref. 21. This teads to considerable underburning of uranium in the discharged peripheral fuel assemblies (PFA), which must be extracted from the reactor at a burnup that is lower than that of the extracted central fuel assemblies (CFA). To increase the burnup of uranium in the PFA's, the peripheral region of the reactor can be charged with uranium of higher enrichment. This is economically advantageous since it reduces the fuel component of the cost of e.lectric energy by several percent; however, it entails production of fuel assembl?es with differing uranium enrichment, and the burnup of the discharged uranium is still less than could be realized by using these fuel assemblies in the center. Let us try to define the conditions under which the burnup of discharged uranium could be increased by transposing PFA's with completion of burnup in the central region of the reactor core. We will consider a two-zone channel reactor in which fuel channel power is equalized by profiling multiplication properties, i. e. k~P > k~c. Let us assume that the law of change in k,,, as a function of uranium burnup P, i. e. k.(P), is lineai and the same for CFA's and PFA's [Ref. 3]. 84 FOR ON Fl('IAL USE: ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 FOR OFFICIAL USE ONLY In the simplest mode of continuous recharging, the central and peripheral regions of the reactor are supFlied independently with the same kinds of fuel assemblies (Fig. 1, I), the uraniian burnup in the discharged CFA's and PFA's being Po and P respectively, where Po> P. This mode does not provide for transpositions and additional burnup of the fuel assemblies, and is the gener- ally accepted mode of operaticn for channel reactors. Another reloading mode can be imagined in which all fresh fuel assemblies ai�e loaded into the peripheral region of the reactor, operated there up to the same uranium burnup as in the first mode, and then transposed and addition- _ ally burned in the center (see Fig. 1, II).. If operation of the reactor in charge charge discharge charge discl}arge chairge po_p I ~ center periphery I center periphery center periphery ! ' I 'p p discharge discharge transposition transposition discharge I II Er Fig. 1. Some modes of reactor recharging: I--independent recharging of center and periphery; Il--all fresh fuel assemblies loaded into the periphery and all additionally burned in the center; III--all fresh fuel assemblies loaded into the periphery, and some additionally burned in the center such a mode is possible, then uranium burnup in the CFA will vary from P to some level P' > P at which the transposed fuel assemblies will be extracted. For continuous transpositions and linear dependence k.,,(P), the condition of criticality for the same profiling of multiplication properties will be the same average burnup of uranium in this region as in the first mode with inde- pendent recharging of center and periphery, i. e. - ~ , whence l'' - 1'� I' . Since P' > P, 1' t !'o/'' . Conditions (1) and (2) are illustrated by Fig. 2. 85 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R000500090007-0 FOR OFFICIAL USE ONLY k~(P knc OD a P) \ 0. ~ - \ -b ~ i po-o vo knc - - 00 P ` I I - - - - ~~-i Fig. 2. Burnup of discharged uranium when the center is Continuing our crnnparison of modes I and II (see Fig. 1), let us assume for the sake of simplic ity that the specific power of the uranium in the CFA's and PFA's (q, MW/kg) is the same and does not change with burnup (P, MW-days/kg). Let the number of CFA's be n, and the number of PFA's be An. Then for mode I the expenditure of CFA's and PFA's per day is vo n(j/l'o; u = iirtqlL'; The average burnup of uranium discharged from the reactor is 1'ore , P" 1 A I I ^ i /I i /~l'p n - ~ ~rn ) ' 1 ^ ~ p / charged with fresh fuel assem- In mode II (if it is possible), the additional blies (a) and with fuel assem- burnup of uranium acquired by the fuel assem- blies with burnup P(b) blies after transposition from the peripheral to the central region will be APC= Po- 2P (s Fig. 2b). Since the central region in this mode is continuously supplied only with fuel assemblies that have been depleted on the periphery, their expenditure in the central region must be equal to the expenditure on the periphery, i. e. nq Anq whence p 1 {^:.':1 p"' Using expressions (1) and (4), we find that the average burnup of uraniiun discharged from the reactor in mode II is . , 1'ii.- - 1-1 11 1 . ~ t I 2A 1~~) Comparing expressions (3) and (5), we readilY see_that mode II is feasible and is more advantageous than mode I(i. e. PII> PI) when condition (2) is met. Thus mode II, in which all fresh fuel assemblies are loaded into the periphery, used there until reactivity is exhausted, and then all fuel assemblies are additionally burned in the center, is advantageous only if the uranium burnup in the PFA's is less than half the uranium burnup in the extracted CFA's in mode I. In reactors of large dimensions, where neutron leakage is small, such a condition is not realizable in practice since it leads to a dip in neutron distribution in the center of the reactor core, and mode IT is infea- sible. However, condition (2) can easily be met if PFA's are broken down into two groups, and rather than transposing all PFA's to the center, we transfer only 86 FOR OFFICIAI. USE: ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00854R000500090007-0 FOR OFFI('IAL l1SE ONLY the PFA's of the first group with relatively low burnup of uraniwa P1< Po/2, while the remaining PFA's are used on the periphery up to some uranium burnup P2 (see Fig. 1, III). Let us consider mode III also in comparison with mode I and let us assume that the specific power of the uranium q in the CFA's and PFA's is the same and does not change during burnup. For mode III, using exactly the same fuel assembli2s, the burnup of uranium discharged from the central region in accordance with expression (1) will be PC= Pp - P1, (6) where P1 is the burnup of uraniwn in PFA's of the `_irst group after utiliza- tion on the periphery. The additional burnup of uraniwn that these fuel assemblies acquire after being transposed and used in the center will be (Pa- 2P1). Since in this case the central region is being continuously made up only with PFA's of the first group, the expenditure of fuel assemblies in the central region vc must be exactly equal to the consumption of PFA's of the first group, i. e. Uc= vi; nq Uc 1'0-'LI" ( (7) t ~ vj= Anqni; where al is the fraction of PFA's of the first group among all PFA's. For a given P1, the value of al is determined from condition (7), and the burnup of discharged uranium in PFA's of the first group is determined from the condition of criticality of the peripheral region that simultaneously ensures the required profiling of multiplication properties: 14 k., ( l') rlP k9P , (8) where az is the fraction of PFA's of the second group, where al+a2= 1. For linear dependence k.(P), criticality condition (8) has the quite simple form ri I p t Consumption of PFA's of the second group is UZ ! .I ttq~,c.~. 1 The average burnup of uranium discharged from the reactor in mode III will be VC~ I.. Using conditions (7), (9) and (10), PIII can be represented as '.:P - 87 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102/09: CIA-RDP82-00850R000500090007-0 FOR OFFI0A1. USE: ONI.Y A study of this expression shows that PIII has a maximum at ~I" .1. It is important that in this case the burnup of uranium in discharged CFA's and PFA's of the second group be the same, i. e. PZ = Pc = Po - P1 � In this case , ;m:ix i AP 111 I1t 1 I A t where Pi~> PI� Thus the operating mode of a reactor in which all fresh fuel assemblies are charged only into the periphery, used there, and then some of the PFA's with optimum uraniian burnup are transposed to the center where they are additionally burned, while the rest of the PFA's are used on the periphery until the reac- tivity of this region is exhausted, is more advantageous than independent reloading of the central and peripheral regions of the reactor. TABLE 1 Relative increase in uraniinn burnup with transposition and operation of some PFA's (_�~Igl-_ in the c enter - t� 1(N), A 1'I'' I _ - I I.n I II,!) I II,N 11,7 I U~Y~ I U,5 I 0,4 I u, ; II~27 11, 11~',',11 I1,25 (1, '-'3 0,20 u,S I5 1 1,24 1,'.'.I 1,ti 1,11 1,02 0,ri4 11,7 :i,'!1 l :i, In :S, 1 I :9,111 '',?ili '._2 ,li! :.','_'ti U'li li,lii 6,1i5 I;,i>.`S li,'J; 6,'215 ~r,,9:; 5,41 4,73 As can be seen from Table l, for the given assumptions and the values of A and P/Po encountered in practice, tlie proposed recharging method enables an increase in burnup of the discharged uranium by several percent with a corre- sponding reduction in the fuel component of cost of electric energy. To check out the approximate results, a stricter two-dimensional model of the reactor was used, enabling accounting for power and energy release of each channel. For this purpose, the heterogeneous QUM-3-HEP program was used [Ref. 41 as well as the VRM and VOR cunstant programs used in designing the RBMK [Ref. 51. Let us note that the given calculations have qualitatively confirmed results of approximate calculations, although they showed ].ess increase in uranium burnup. For example at A= 0.36 and P/Pp= 0.78, burnup increase was -0.7%, :is against 1.3% according to the data of Table 1. Refir.ement is mainly by considering equalization of the neutron field with transpositions of fuel assemblies, leading to some increase in neutron leakage, and also by con- sideration of nonlinearity in the behavior of multiplication properties of t}ie medium with uranium burnup. Calculations showed one more advantage of the given method of reloading, which shows up in additional equalization of energy distribution due to transposition 88 FOR OFFICIAI. I.JSF. ONLI APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2007102109: CIA-RDP82-00850R000500090007-4 FOR OF'F(CIAL USE ONLY of partly burned fuel assemblies rather than fresh ones into the center, i. e. into the region with maximum neutron flux. If reloading is done on the worl.ing reactor, equalization may be intensified by 13sXe in the transposed fuel assemblies. This advantage becanes especially important when an economically advantageous increase in uraniwn burnup by simply raising its initial enrich- ment is impossible due to an inadmissible increase in the coefficient of non- uniformity of energy distribution because of heat-transfer conditions. Such a situation is typical of reactors in which the minimum necessary reserve is provided up to the limiting power of the fuel channels, and in particular for the RBMK-1500 and the RBMKP. The model indicated above was used for calculating steady-state conditions of recharging the block-section RBMICP-2400 reactor with nuclear superheating of steam [Ref. 6, 71, in which the plan provides for the given method of load changing. Consideration was taken not only of the configuration and makeup of the core (Fig. 3), but also of the fact that the power of the superheated channels must be approximately half that of the evaporative channels, and the region of elevated neutron flux density of the evaporative zones is made up of the central regions of these zones, whereas in the superhea ted zone the superheated channels in rows bordering on the zone of the evaporative channels make up the regions of high neutron flux density. The evaporative ~ �s _ I w I CFA ~ Iw I P .a L zone_ SC zone . Fig. 3. Structure of the left half of the RBMKP-2400 reactor core. The broken line shows the boundaries of sections (the core consists of eight identical evaporative channel (EC) sections and four superheated channel (SC) sections. Each section contains 270 channels: 240 fuel channels and 30 for control rods) fuel assemblies are reloaded and transposed during operation of the reactor, all Eresh fuel assemblies heing installed only in three peripheral evaporative channel zones, from which some are transposed to the center. The superheated fuel assemblies are reloaded and transposed with the reactor shut down, about 5% of the channels being renewed at one time. In the superheated zone, fuel ussemblies are transposed from the three peripheral rows only to the three rows of superheated channels bordering on the evaporative channel zones (Fig. 3). No transposition of fuel assemblies is provided in the other regions of the superheated zone. To simplify spatial calculations, a fixed periodic structure of the reactor core was assumed. Certain average values of uranium burnup were assigned to the fuel assemblies transposed aad reloaded from each region. In each 89 FOR OFFICIAL USE ONLY APPROVED FOR RELEASE: 2007/02/09: CIA-RDP82-00850R000500090007-0 APPROVED FOR RELEASE: 2407102109: CIA-RDP82-00850R000500490007-4 F()R OFMI('IAL l1tiE ONI.Y region the distribution of the remaining fuel elements with respect to ura- nium burnup from the fresh or transposed assembly to the unit about to be discha;Ked or transposed was taken as discrete and uniform. Compensation of operative reserve reactivity was also fixed by control rods. All this enabled us to do variant calculations with minimum changes in load charting records without considering the history of each fuel assembly. Criticality and the required energy distribution in the reactor were ensured by varying the sought average values af uranium burnup in the fuel assemblies at discharge or trans- position. TABI.E 2 Some characteristics of the RBMKP-2400 fuel cycle for different methods of i�:loading fuel assemblies I Without transposing I With transposition Characteristic fuel assemblies of fuel assemblies SC Enrichment of uranium to be 2.0 3.0 2.4 3.6 loaded, % Average burnup of discharged 21.9 24.7 27.7 30.5 uraniwn, MW-dayE /kg Specific consumption of en- 28.8 6.4 22.9 4.8 riched uranium, metric tons/GW-yr* Specific constunption of natural 108.6 37.9 106 35 uranium required for getting ura- nium oE appropriate enrichment, metric tons/GW-yr* Fuel component cost of electric 1 .0 0.91 energy, relative units *Power utilization factor was 0.8. Calculations done at the same values of limiting power of the evaporative and superheated channels showed that the proposed transpositions of fuel assemblies into the region of elevated neutron flux density ean appreciably increase the enriclunent and burnup of ur