SOVIET ATOMIC ENERGY - VOL. 39, NO. 4

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April 1, 1976
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Declassified and Approved For Release 2013/09/24: CiA-RDP16-02196R000406060003-2 ? ? 5 ' - Russian Original Vol 39,Noi4, octob,er, 1975 1976 ? \,, ,, ,,,,-- '? , , V. '. -`, ' ? , ,.) / " ' ? ? A' ( '- .'l . .? .) . , --. ; 1, A% ' , \ ? " --- , .., ... ), .. \ ? N ....,. . .,... - ?--- - ... SATIAZ ,89t4).?863,952? (1975)- - / - ,,-,-: ?\ ' , , . --i,,, , /,? ,, . ...?, , ) . r- ? -? - - L ATOMH;d1 (ATOPANAY A ,gNE,R9IY A) ) \ 2 \-, ''' -.?, 0 [. ? H . N. ; /7 , y, \ 7 ' :/ ''?'' , , \. j) --- ' '' , , , TRANSLATED FROM, RUSSIAN, - ? ; -?, .. , ,. -!., , ? , . ,.... ? . , / ? \-- -\ ), I , (--, . -? ? L / c ,'.; - % ( ,! , , . ' '- , - , >-..,\,' _.. -\ :c ic / / 1 ) ' '"N k - 'N '4) ' - ) ? I -, ?? ,- \?- , , -CONSUIO PTS\ BUREAU NEW YORK' \ ), A ? - / ? , Declassified and Approved For Release 2013/09/24: bIA-RDP10-02196R000400060603-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 1, , , ,, ; , , - :,7 , I.', --\ -,1,,,, / , - ' - - rz?,,,,,_ ?I i ._,--- ,-- ---- ,\_ ,'- `i i , J j , Soviet Atomic'Enerby is a co-ver-to-cover translati6n-of Atomnayq, . , Et-lrgiya, a?615;lic.ati,dn 8t,theYAcademy of,S0en.cee of the USSR. -----', ? . - , r ?, . - , - Soviet Atomic Energy is' abstracted of in- dexed in Applied-Mechanics Reviews,' Chem- ical Abstracts, Engineering Index,,INSPEC? Physio's Ahsbacts and :Electrical' and ,Elec- tronici (-Abstracts, ;Current Contents, and -:-Nualear Science Abstracts, ....') -- Ati, agieement with-thedopyright AgericY:oi'thi USSR (VAAP) , , , , , tnakevavallable both advance copies ofithe Russian fOurnal and ?. ? deiginal. glassy Photograrphs an4:.a,rtwork-.7This-erves to deCre-* ._ the -necessary time lag\between publication -ollthe original anel...`, . publication of 'thetranstatiOn andhelps.loirnprovi theflyatity . of, the latter. The "t'ran'slation .begari with, the first issue of the - - tRussianjournal. , . .., . , - --,--\-:,...;' :,, ? - -_-, 17 . r.-- 2 ?,' , , - - - - / Editorial Board Of,Atomn\aya Energiya:-i -- - ( , _ 7- , ,. _ 1 , - . ,.,, . . , --- i ? Editor: MI D. Millionahchikov L - - `P? . + P , - DeputY 6Irectof - ? -: I. ?V. Kurchatpv 'Instltute'of.,AfornieEner0 - h-._' f ,;? Academy of Sciences of the USSR., \ ? _ - Mopcow, USSR r ,? ) ' 1 -- i . ' (----, s 5 .c- ., ---', AisOciate Editor: N. A-VlasciV k., , ? , 1 I5. k: ? ' (5A ' A. A. Bochvar ?, ? , - N. A,. Dollazhar " X/..--S.:Fiirsov, I. N bolOvirw - ? --"I', , , \IF. Kg1I0in, ) sTr- ) A. I.,-Krasin ,. * , , - \ , .\ 7- I- V. V. Matveev; ') , m: MeshcheryakoV ? ? - / P. N. Palei - - Shevchenko- ' _ P. Vinogradov r- Ap:zefirv - ' ? ---.. I 7 ../i ' . , ? Copyright? 1976 Plenum ,P6 ,F'ublshing Cor..poralion, 227 West-17th Street/ New', York, ' - W.Y. 10011. All rightS\ reserved. No article containecNherein 'may be,reprouced, 7 .,''' stored in a retrievallsystem, or transmitted, in ,any form or by any meakielecfr'onic, - --- mechanicel,'Phot-POopying; microfilming, rec.cird'ing or otnerWise,. vvithdut written ? A - A- '-.-- ? /Permission' of the publisher. ' . ' / ? , .. ) 7, .. \ , , . , ?,..? ' .._._? \ . _..,.. . r / Consultants Bureaujournalt appeai- about six-months after5the publication of the ' original ,Russian issue. For ;bibliographic accuracy, the Er'1611sh :issue publihed Vi'L / -)'Const.iltant Bureau cari'les.the-tame number anci`clate as the'o4inal.hussian from 7 i - ,/ _. whi'ch t was translated. FOr-example, a Russian issue publisheein-December will '. appear in a'.COns`ultants.Bureau' English translation a6Pul-the following ..1-Zine, but the ? ,( tranda0on issue will carry the (5ecembe5date.'When ordering any volume or particu- ,--? / _ lar issue/of .,e_ Coni"urtants Bureau' :journal, plea'se specify the date and, Where appli- /cable.. the volume and !issuefew York, New-York 160,11 - V, , \ . / - r, 7 ! 7 , 1 ? Published monthly. 'Second-class-postage-paid at Jamaica ;? New York- 11431. f 5' -7-` 7 \' ./ '\.' \ ' -7--'' 1 ' - ' ) ? )- , . ) . . ._ , . ? , -% . . . ?.', ..,..._ ,.,..(..--,, ? ,- 1- , ''-. ). /' Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003:2 " Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 SOVIET ATOMIC ENERGY A translation of Atomnaya Energiya April, 1976 Volume 39, Number 4 October, 1975 CONTENTS Engl./Russ. ARTICLES Radiophotochemistry as a Possible Basis for the Efficient Use of Two-Purpose Reactors ? V. I. Goltdanskii 863 243 Experimental Double-Fuel-Element Channel for the Reactor of the World's First Nuclear Power Station? M. G. Bul'kanov, V. A. Kurov, V. D. Lazarevskaya, V. G. Potolovskii, and V. S. Sever'yanov 867 247 Statistical Characteristics of the Temperature Fluctuations in a Direct-Flow Sodium?Water Steam Generator ? B. V. Kebadze, V. S. Sroelov, B. V. Kul'min, and A. I. Gavrilin 870 250 Analysis of the Conditions Required for Producing Highly Purified Carbide Fuel by Reducing Oxides with Carbon, and Study of the Behavior of Oxygen and Carbon Impurities in the Presence of Fission Products ? R. B. Kotel'nikov, V. S. Belevantsev, S. N. Bashlykov, G. V. Titov, V. A. Zelyanin, and A. M. Anuchkin 874 255./ Simulation of the Formation and Annealing of Defects in Regions of Damage Created by Collision Cascades in Alpha Iron ? P. A. Platonov, V. F. Krasnoshtanov, and Yu. R. Kevorkyan 879 260 Determining the Proportion of Plutonium Nuclei Undergoing Fission during the Burn-Up of Slightly Enriched Fuel? K. I. Zykov and 0. A. Miller 884 265 Technological Sensitivity Factors in Atomic Electric Power Plant Optimization ?A. M. Kuz'min 888 269 Use of Internal Direct-Charge Detectors as Input Elements of Automatic Reactor Control Systems ? M. G. Mitel'man, L. G. Andreev, I. V. Batenin, B. G. Dubovskii, V. A. Zagadkin, V. F. Lyubchenko, K. N. Mokhnatkin, N. D. Rozenblyum, V. S. Sever'yanov, V. B. Tregubov, Yu. M. Shipovskikh and A. I. Shtyfurko 892 272 An Investigation of the Transition Effect in Layered Absorbers ? V. I. Vittko, I. A. Grishaev, and G. D. Kovalenko 895 275 DEPOSITED PAPERS Phase Extension of a Relativistic Electron Bunch Interacting with a Resonator in a Storage Ring ? S. G. Kononenko, N. I. Mocheshnikov, and N. N. Naugol'nyi 899 279 Reliability of Electron Accelerators for Radiochemical Devices ? Yu. D. Kozlov 900 280. Spectral Distribution of the Albedo of 137CS 'Y. Radiation for a Two-Layer Medium with a Cylindrical Interface ? Yu. B. Davydov, A. A. Timonov, and A. V. Davydov 901 281 Optimization of the Health Protection Zone and Shield Parameters for Accelerators ? Yu. A. Volchek and A. Ya. Yakovlev 902 281 LETTERS Elemental Analysis of Boron Carbide and Initial Components by Proton-Induced X Rays ? A. G.Strashinskii, G. K. Khomyakov, N. A. Skakun, N. V. Serykh, and I. T. Ostapenko 904 283 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 L Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 CONTENTS Cross Sections and Resonance Integrals for the Fission of 239Pu, Am, Cm, and 249Cf (continued) Engl./Russ. ? K. D. Zhuravlev, N. I. Kroshkin, and A. P. Chetverikov ? ? . 907 285 Instrumental Neutron Activation Analysis of Geological and Biological Objects Using a Computer? V. B. Zlokazov, L. P. Kul'kina, and 0. D. Maslov 909 286 Determination of Manganese in Aluminum by Neutron Activation with a 252Cf Source ? K. Sailer, Sh. Darotsi, Sh. Nati', P. Raich, I. Chikai, and L. Gergei 911 288 Some Results of an Examination of a Dismantled RK-L Hot Loop ? D. M. Zakharov, V. V. Gavar, A. S. Dindun, and M. M. Kramer 913 290 Ratio of Radiative Capture and Fission Cross Sections for 239Pu at Neutron Energies of 0.2-30 keV ? A. A. Bergman, A. N. Medvedev, A. E. Samsonov, and V. A. Tolstikov 916 291 Evolution of Hydrogen from Proton-Irradiated Construction Materials ? Yu. P. Vasin, A. G. Zaluzhnyi, D. M. Skorov, and 0. M. Storozhuk 919 293 Cross Section for the Fission of 240Pu by Neutrons from a Nuclear Explosion ? E. F. Fomushkin, E. K. Gutnikova, G. F. Novoselov, and V. I. Panin 921 295 CONFERENCES AND CONGRESSES Problems of Increasing the Service Reliability of the Metal in the Power Equipment of Nuclear Power Stations ? L. M. Voronin and E. P. Karelin 923 297 Second All-Union Radiogeochemical Conference ? R. P. Rafarskii 925 298 All-Union Conference on the Chemistry of Neptunium and Plutonium? A. M. Rozen . 929 301 The Third All-Union Conference on Linear Charged-Particles Accelerators ? I. A. Grishaev 932 302 The 2nd International Symposium on Nuclear Electronics ? A. N. Sinaev 934 303 Principal Results of the April Session of the International Commission on Radiological Protection (ICRP) ? A. A. Moiseev 937 305 The Third European Congress of the International Radiological Protection Association (IRPA) ? V. N. Lystsov 939 306 Isotope Ratios as Indicators of Radionuclide Sources and Environmental Migration Paths ? R. M. Aleksakhin 942 307 EXHIBITIONS "Inventions and Branch Licensed Products" Exhibitions in the "Atomic Energy" Pavilion at the Exhibition of Achievements of the National Economy of the USSR ? B. A. Sokolov and E. A. StrePnikov . 944 308 NEW INSTRUMENTS AND TECHNOLOGICAL PROCESSES LBK fl Potassium Concentration Meter ? L. V. Matveev, 0. G. Mikhailov, and E. A. Strel'chenko 946 309 A New Method of Regeneration of Traps for the Purification of Alkali-Metal Coolants ? L. G. Volchkov and F. A. Kozlov 948 310 BOOK REVIEWS D. Bedenig. Gas-Cooled High-Temperature Reactors ? Reviewed by Yu. L Koryakin . . 949 311 Msdrgs6rit Pavelscu. Numerical Methods for the Calculation of Nuclear Reactors ? Reviewed by S. M. Zaritskii 951 311 The Russian press date (podpisano k pechati) of this issue was 9/25/1975. Publication therefore did not occur prior to this date, but must be assumed to have taken place reasonably soon thereafter. Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 ARTICLES RADIOPHOTOCHEMISTRY AS A POSSIBLE BASIS FOR THE EFFICIENT USE OF TWO-PURPOSE REACTORS V. I. Gol'danskii UDC 621.039.335 The recent extensive development of nuclear power has given rise to the extremely important problem of creating two-purpose reactors producing both electrical power and chemical products. Reactors of this kind may be considered with some justification as the basic installations of future large-scale radiochemical production [1-4]. A number of fundamental ways in which two-purpose reactors may be used for chemical production have been discussed in the literature, and these we shall now consider. Chemonuclear Synthesis. This version is the most direct method of converting nuclear energy into the energy of endothermic chemical processes. The five stages involved in the trivial use of a nuclear reactor as an energy source for chemical production are replaced by a single stage (Fig. 1). The chief part of the fission energy ? the kinetic energy of the fragments retarded in the reaction mixture (the pro- portion of fission energy carried away by the fragments f = 0.85) ? is in this case directly harnessed for chemical requirements. The mechanism underlying the conversion of the fission fragment energy into chemical energy in the gas phase is purely radiochemical; in the condensed phase this effect may be sup- plemented by the thermochemical action of the fragments [5, 6], associated with the formation of micro- scopic regions of brief local heating along the tracks of the fragments. The radiation yield of the trans- formations taking place under the influence of the fragments lies in the range G 1-10 for ordinary (not chain) reactions, where G is the radiation yield (the number of fully reacting molecules per 100 eV energy of the ionizing radiation), and differs little from that encountered in other forms of radiation [7]. The necessity of minimizing the primary radioactive contamination of the products of chemonuclear synthesis (evenbefore subjecting these to specialpurification) compels us to use special highly dispersed chemonuclear elements or cells ("chels") as nuclear fuel; these have a certain optimum pore size, en- suring the liberation of a high proportion of the fission-fragment energy in the interior of the reagents, the fission fragments then emerging from the latter and being retained in the walls of the chemonuclear cell. This acts as a kind of self-filtration of the chemonuclear cell from radioactive contaminants [8-14]. The proportionp ofifission energy transferred to the reagents under optimum conditions is 0.3 [9]. Allowing for all these factors, the yield of chemonuclear-synthesis products for one act of fission of the nuclear fuel (E ? 200 MeV) is approximately 2 ? 108(G/100)fp 5? 105 G. Here and subsequently we shall take the fixation of nitrogen (M = 28) as a typical example; taking G = 1, we then obtain a yield of Wchn 60 kg/g U for the chemonuclear synthesis. However, remembering that after the elapse of a time t 10 sec from the instant of uranium or plu- tonium fission the total activity of the fission fragments of 1 g of nuclear fuel equals 3.1011 t-1,2 Ci [15], it is easy to see that in the absence of further purification the activity of the chemonuclear synthesis prod- ucts will be 5.106 t-192 Ci/g, i.e., in four or five days Actin ? 1 Ci/g. Requirements imposed upon the purification of chemonuclear-synthesis products are extremely strict (purifications of the order of 106-1012 times are demanded); this makes the technology of chemonuclear pro- cesses more expensive and (even more important) makes them partially or even entirely incompatible with the elimination of pollution from the environment. Translated from Atomnaya Energiya, Vol. 39, No. 4, pp. 243-246, October, 1975. Original article submitted March 4, 1975. ?1976 Plenum Publishing Corporation, 227 West 17th Street, New York, NY. 10011. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission of the publisher. A copy of this article is available from the publisher for $15.00. 863 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 8 Light energy Nuclear ener 2 Thermal gy Alienergy Chemical energy Thermal energy 3 Mechanical energy Electrical energy Mechanical energy 7 Fig. 1. Various ways of converting nuclear into chem- ical energy: 1-2 ?3-4 ? 5-6) ordinary way; 1 ? 6) chemonuclear synthesis; 1 ?2 ? 6) high-temperature fuel element version; 1 ?8-6) radiophotochemical syn- thesis. Synthesis Using High-Temperature Reactors. The two-stage conversion of nuclear energy into chemi- cal energy via a thermal stage (Fig. 1) was proposed and examined in relation to the oxidation of nitrogen in [16]. Here it is essential to use high-temperature fuel elements; however, an extremely important ad- vantage of this version is that there is no direct contact between the fission fragments and the reagents, so that the radiochemical purity of the products of the chemical processes is assured. The yield of combined nitrogen for fuel-element temperatures of 1900-2500?C is (according to the estimates of [16]) w -temp ? 200- 360 kg/g U (Wtemp increases further in this case as the result of a chain reaction in the oxidation of nitro- gen). A high yield of the desired products is achieved by the successful combination of high-temperature kinetics and the rapid cooling of the reaction products, i.e., the quenching of the favorable high-tempera- ture equilibrium. Unfortunately at the present time there are no fuel elements capable of prolonged opera- tion without failure at can temperatures of 2000?C or even lower temperatures. Chemical synthesis in high-temperature nuclear reactors thus remains for the time being a purely speculative version. Synthesis under the Action of Mixed ny Radiation from Nuclear Reactors. Even in the case of special reactor constructions ensuring the maximum use of mixed ny radiation for chemical purposes, the power of these radiation sources is no greater than 1-6% of the thermal power of the reactor [1]. Hence the yield of the desired product is only Wiry' (2.5-15) kg/g U, i.e., far lower than in chemonuclear synthesis. The danger of radioactive contamination (activation) of the synthesized products of the radiochemical processes nevertheless remains (although to a less serious extent than in the case of chemonuclear syn- thesis); this contamination often includes radioactive isotopes of elements entering into the composition of the products which are incapable of being separated chemically. Averaging the data presented in [1] we obtain the following relationship (typical for the case of mixed ny radiation), being the integrated dose of irradiation and the integrated thermal neutron flux: F/D ? (2-3) ? 1014 neutrons/(cm2?Mrad). It is thus easy to see that the formation of every gram of the desired product in typical nitrogen- and hydrogen-containing systems in a field of mixed ny radiation with a radiation yield of G 1 will be accom- panied by the accumulation of ?10-1 Ci of I4C and ?2 .10-2 Ci of tritium distributed between the original reagents and the radiochemical-synthesis products, in proportion to their contents of nitrogen and hydrogen molecules. Although these activities are many orders of magnitude smaller than those encountered in chemo- nuclear synthesis, they are still quite unacceptable. It is clear that the large-scale manufacture of chemi- cal products involves the creation of serious radioactive contaminants, the necessity of reliably separating these from the chemical products, and necessarily a high degree of purification of the original reagents from impurities liable to be severely activated by thermal neutrons (for example, halogens, sulfur, a large number of metals, and so on). All this may make the technology of chemical synthesis under the action of mixed ny radiation from nuclear reactors more expensive, so greatly limiting its practical value. 864 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Synthesis in Radiation Circuits. According to the results presented in [4], the power drawn from re- actors in the form of the activity of the radiation circuits may be estimated as -1% of the electrical power of the reactor, which amounts, for example, to -108 g-eq ?Ra for an electrical power of 100 MW or a thermal power of 100/K MW, where K is the thermoelectric energy-conversion efficiency. From this we may estimate the yield of end product as Weirc GK ? 1.7 kg/g U, which, although well below even the mixed n7-radiation output, nevertheless has a considerable qualitative advantage (the products contain no radioactive contaminants). Hence the use of radiation circuits is at the present time the most promising version of the radiochemical use of nuclear reactors [4]. Radiophotochemical Synthesis. One further possibility of two-stage transformation remains promis- ing, that of nuclear ? light ? chemical energy (Fig. 1). In this version the fuel elements act as photochem- ical elements or cells ("fels"); the fission fragments are retarded in specially selected (solid or gaseous) scintillators, while the light so created is focused by a set of reflectors into the ends of glass-fiber or other light guides, which bring this light into the zone of photochemical transformation. The yield of the end product Wphch - 18,000 4:11a/E kg/g U, where (13 is the fragment/light energy conversion coefficient (the so-called light yield), E is the energy of the light quanta in eV, a is the quantum yield of the photo- chemical reaction, allowing for the incomplete focusing of the light into the photochemical zone (in the present case there is no need to concern oneself with stopping the fission fragments in the interior of the scintillator, so that the factor p encountered in Wchn is no longer required). There are certain scintilla- tors for which 41 reaches -0.1, for example, c13. 0.08 in NaI(T1) and (1) 0.15 in CaI2(Eu), the value of .13 not depending on the ionizing capacity of the particles but being the same for both p particles and fragments [17]. For E 3 eV and a - 0.1 we then have Wphch^- 60 kg/g U. Of particular interest for radiophotochem- ical synthesis are gaseous (rather than solid) scintillators of the xenon type, possibly with the addition of light converters for displacing the center of the scintillations from the ultraviolet to the visible region at pressures amounting to tens of atmospheres. As in the case of synthesis with the aid of radiation circuits, the products of radio photochemical syn- thesis contain no radioactivity. The yield of these products may, in fact, be much greater than that of the circuit version, and (a factor of no mean importance) the perilous necessity of removing radioactive ma- terials (activity carriers in the circuits) from the active zone of the reactor is avoided (this procedure is replaced by the collection and transmission of light). Naturally it is desirable to ensure selectivity of the chemical transformation, and the preferential yield of a prespecified product. This may be done more easily in a photochemical transformation than in a radiochemical process, for example, by choosing the appropriate light converters so as to optimize the light of the radiophotochemical sources as regards intensity and spectral composition. We should take note of some important initial successes in the conversion of fission fragment energy into not simply monochromatic but also coherent light, involving the use of nuclear reactors to pump lasers [18, 19], the efficiency of the nuclear/laser energy conversion reaching several percent.* Of course there are a number of problems in which photochemical interaction cannot replace radio- chemical processes (as in chemical transformations, or the modification of materials opaque to visible light or other radiations close to the optical region); however, there may also be processes in which radiopho- tochemical synthesis may prove to be the best method of using nuclear energy for chemical purposes and may provide a firm basis for the operation of the most economic two-purpose (power and chemical) nuclear reactors. Investigations into the following problems of radiophotochemical synthesis are thus extremely vital: 1. The choice of systems ensuring the maximum conversion factor for the transformation of kinetic fission-fragment energy into light energy (it is desirable to obtain a monochromatic or bright-line light spectrum of photoradiation origin, the radiative pumping of lasers being of particular interest). 2. Provision for the most efficient method of collecting and transporting light from the active zone of the reactor (this requires, in particular, a high radiation resistance of the scintillator, which should clearly be of the gas type), and also the transportation of the whole system of light reflectors in the active zone and the initial section of the light guide from the active to the photochemical zone. *We are not here considering other aspects of interaction between laser and radiation-based processes, such as the possibility of increasing the radiation resistance of chemical compounds or improving the se- lectivity of radiolysis by using laser beams as a background to the irradiated substances [20, 21]. 865 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 3. Choice of the best photochemical processes, with the allowance for the requirements of the chem- ical industry, the emission spectra of scintillators severely irradiated with fission fragments, and also the possibility of using various sensitizers and spectral converters. LITERATURE CITED 1. A. Kh. Breger et al., Fundaments of Radiochemical Apparatus Construction [in Russian], Atomizdat, Moscow (1967), p. 500. 2. V. I. Golidanskii, Vestn. Akad. Nauk SSSR, No. 9, 62 (1970). 3. Ya. M. Kolotyrkin and V. L. Karpov, Zh. Vses. Khim. Obshch. im. D. I. Mendeleeva, 18, 242 (1973). 4. A. Kh. Breger et al., ibid. , p. 312. 5. V. [Goldanskin and Yu. Kagan, Intern. J. Appl. Rad. and Isotopes, 11, 1 (1961). 6. E. A. Borisov, L. A. Bulanov, and E. V. Starodubtseva, Khim. Vys. Energ., 4, 550 (1970). 7. V. I. Gordanskii et al., At. Energ., 30, No. 3, 262 (1971). 8. P. Harteck and S. Dondes, Nucleonics, 14, 22 (1956). 9. M. Steinberg, Chem. Engng. Progr. , 62, 105 (1966). 10. M. Beller, L. Epel, and M. Steinberg, Chem. Engng. Progr, Symp. Ser., 63, 71 (1967). 11. V. I. Gol'danskii et al., Izotopy v SSSR, No. 12, 7 (1968). 12. B. G. Dzantiev et al., At. Energ., 29, No. 2, 71 (1970). 13. B. G. Dzantiev, A. K. Krasin, and V. T. Kazazyan, At. Energ., 33, No. 6, 803 (1972). 14. E. A. Borisov and V. D. Timofeev, Zh. Vses. Khim. Obshch. im. D. I. Mendeleeva, 18, 323 (1973). 15. S. Glasstone and M. Edlund, Fundamentals of Nuclear Reactor Theory [Russian translation], IL, Moscow (1954), p. 460. 16. Ya. B. Zel'dovich, V. I. Gol'danskii, and B. G. Dzantiev, in: Fixation of Atmospheric Nitrogen [in Russian], GIAP, Moscow (1963), pp. 35-43. 17. V. V. Matveev and B. I. Khazanov, Instruments for Measuring Ionizing Radiations [in Russian], Atomizdat, Moscow (1967), p. 697. 18. L. I. Gudzenko, I. S. Slesarev, and S. I. Yakovlenko, Preprint 109/1974 of the P. N. Lebedev Physical Institute, Academy of Sciences of the USSR. 19. T. Wimett, H. Helmick, and R. Schneider, Science News, 106, 229 (1974). 20. V. I. Gol'danskii, Khim. Vys. Energ., 9, 78 (1975). 21. V. Golidanskii, Intern. J. Radiat. Phys. Chem., 7, 339 (1975). 866 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 ? EXPERIMENTAL DOUBLE-FUEL-ELEMENT CHANNEL FOR THE REACTOR OF THE WORLD'S FIRST NUCLEAR POWER STATION M. G. Bultkanov, V. A. Kurov, V. D. Lazarevskaya, V. G. Potolovskii, and V. S. Severtyanov UDC 621.039.5 The construction of new types of fuel elements requires that reactor tests be carried out on both the fuel components and on experimental half-scale fuel elements. The channel being described is intended for verifying, under the conditions of the reactor of the world's first nuclear power station, new technical solutions for the fuel elements of the Beloyarsk nuclear power station and the Bilibinsk nuclear heat and electric power plant. The positive experience accumulated on the basis of tests of unique experimental fuel elements has enabled an experimental channel to be constructed which, when loaded with fissile ma- terial, is identical with the regular-fuel-element channel and can be used in place of it. The channel is designed for a regular cell of the reactor of the world's first nuclear power station and has the same subcoupling dimensions. In the construction of the channel, certain improvements are taken into account which were adopted in the channels of the Beloyarsk nuclear power station and the Bili- binsk nuclear heat and electric power station, and directed at increasing their efficiency. The experimental channel (Fig. 1) consists of two fuel elements, descending and ascending tubes, installed in metal and graphite sleeves, which form a cylinder with diameter 64 mm for the graphite sleeve and 63 mm for the steel components. The length of the channel is 6.6 m. The coolant from the conduit reaches the dispensing collector through a connecting tube and an inlet central connecting pipe, and enters the pressure chamber located in the lower part of the channel through two descending tubes with diameter 12 x 0.6 mm. The coolant passes upwards, washing the inside surface of the fuel element tubes, from the chamber through spiral tubular compensators, which take up the tem- perature expansions between the descending and ascending tubes. Later, the coolant enters the collecting vessel and leaves the channel through a side connecting pipe. The dimensions of the fuel elements are: TABLE 1. Results of Fuel Element Tests in the Experimental Channel Cell Cell designation Date of in- sertion (1970) Date ofremoval Bumup, kg/t Av . heat flow, , 106 kcal/m- Temp.of fuel lement clad- ding, ac 05-14 DTM-87 22.V 12.1.74 20,3 1,31 400 05-08 DTM-88 10.V1 12.1.74 18,5 1,13 380 05-18 DTM-90 6.IX 12.1.74 17 1,36 420 09-16 DTM-92 29.VI 12.1.74 17,1 1,56 430 12-19 DTM- 93 10.VIII 12.1.74 16,4 1,16 390 08-15 DTM- 95 10.VIII 12.1.74 18,1 1,7 440 11-12 DTM- 96 3.X 12.1.74 17,2 1,3 400 09-18 DTM-86 21.V 15.111.72 6,5 1,5 430 04-11 DTM-85 21.V 7.X.73 17 1,23 390 01-12 DTM-84 21.V 7.IV.72 5,1 1,19 390 06-13 DTM- 94 13.VII 6.1V.72 5,3 1,5 430 13-10 ?DTM-91 28.VI 7.X.73 13,1 1,1 380 08-19 DTM-89 18.VII 7.X.73 16,5 1,0 360 02-11 DTM-99 11.1X Being tested 15 1,21 . 390 10-05 DTM400 8.IX Being tested 14,5 1,16 390 03-20 DTM-97 8.1X 6.1V.72 4,95 1,35 410 05-04 DTM-98 11.IX Being tested 16,7 1,17 390 Translated from Atomnaya Energiya, Vol. 39, No. 4, pp. 247-249, October, 1975. Original article submitted October 7, 1974. ?1976 Plenum Publishing Corporation, 227 West 17th Street, New York, NY. 10011. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission of the publisher. A copy of this article is available from the publisher for $15.00. 867 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 A-A (A% diameter of the surrounding cladding 20 x 0.2 mm and inside tube 12 x 6.6 mm.* The compensators are made of tubes with diameter 9.4 x 0.6 mm and have a spiral pitch of 30 mm. Below the distributing and collector vessels are assembled the metal plugs of the biological shield, with openings 12x 0.6 mm diameter below the tube. The lower plug is braced to the outside jacket, made from 63 x 1.5 mm tubing. The jacket is connected with the channel head and is a load-carrying structure for the plugs of the biological shield. The lower part of the descending tubes and the fuel element are enclosed in graphite sleeves. The opening in the center of the sleeve, with diameter 10 mm, is designed for emergency withdrawal of the channel from the reactor cell. In the zone of the compensators, graphite sleeves are arranged for cen- tering them. In the experimental dual-fuel-element channel, with ther- mometry of the outside cladding of the fuel element, additional an- nular recesses are provided in the graphite sleeves for positioning the bracing units of the thermocouples and openings for their lead- out. A special packing gland is provided at the channel head for the thermocouple lead-out. There is also a fitting for the pressure bleeder. ? Chromel? Alumel cable-thermocouples, type KTMS, were used, of size 2 x 0.06 mm, and which had shown excellent efficiency. Measurement of the temperature of the thin-walled cladding of the fuel elements is one of the most complicated types of reactor ther- mometry. Most frequently, a bracing is used for the hot junctions of the thermocouples by means of clamping or bimetallic rings ?_ 10 j this is a unique method of avoiding damage to the fuel-element cladding (Fig. 2). A considerable drawback of this method is the loss, in the course of time, of the clamping properties of the ring which leads to breakdown of the contact between the cladding and the thermocouple hot junction, and to the appearance of an error in the thermocouple readings. The channel components are made from grade 12Kh18N1OT stainless steel. For avoiding cracks, thin-walled tubes with diame- ter 12 x 0.6 and 9.4 x 0.6 mm were welded only with butt seams. In order to form the necessary space for the radial expansion of the fuel elements during swelling and for reliable monitoring of the leak-tightness of the fuel elements, the gaps between them and the graphite sleeves are 0.5 to 0.7 mm (at the side). Heat from the graphite stack is removed largely through descending tubes, disposed in the graphite sleeves and with a minimum gap of about 0.15 mm. Part of the heat from the graphite is also transferred to the fuel elements. In order to reduce the corrosive action of the reactor medium on the fuel-element cladding and tubes of the channel water circuit, provision is made for purging the channel with nitrogen. In order to ensure a reliable purging of the entire channel cavity, the compensation zone is enclosed on the outside with a tube of diameter 63 x 1.5 mm, which has three openings 20 mm in diameter for outlet of the gas. Gas gaps are used also for monitoring the leak-tightness of the outer cladding of the fuel elements and the channel tubes, and this is effected by pumping out gas through the gaps and measuring its radioactivity. A connecting pipe, located in the head of the channel, is used for feeding in the gas. In channels with temperature measure- ment of the outer fuel-element cladding, this connecting pipe is located at the thermocouple outlet joint. The principal technical data and operating conditions of the standard and experimental fuel channels are given below [1, 2]: Fig. 1. Experimental double fuel element channel: 1, 2) inlet and outlet pipes for coolant of the first loop; 3) channel head; 4) steel sleeves; 5, 6) descending and as- cending tubes; 7) graphite sleeves; 8) fuel element; 9) compensator; 10) rotary chamber; 11) thermo- couple outlet assembly; 12) pres- sure bleeder pipe. *Channels of this design allow fuel elements with maximum external diameter of up to 25-26 mm to be tested in the regular reactor cells (diameter 65 mm). 868 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 1 3 1 2 4 Weld clamp Fig. 2. Methods of securing the regulus of a thermocouple by means of a shoe (a) and a strip of foil (b): 1) thermocouple; 2) clamping ring; 3) shoe; 4) strip of foil. Working pressure, kg/cm2 . ? 100, 100 Water temperature, ?C at inlet at outlet 180-190, 270-309, 180-190 270-309 Coolant flow rate, t/h 1.9-2.4; 1.2-1.5 Average thermal flow from fuel element to water, kcal/m2?h (0.8-L8) ? 106, (1-1.7) ? 106 Maximum temperature of outer cladding of fuel element, ?C 450, 450 Uranium charge in channel, kg 4, 4 Number of fuel elements, pieces 4, 2 Active length of fuel element, mm 1700; 1700 Outside diameter of fuel element, mm 14 x 0.2, 20 x 0.2 Diameter of central tube of fuel element, mm 9 x 0.4, 12 X 0.6 Quantity of steel per channel, cm3/cm 1.05, 1.2 The design of the channel permits the fuel elements to be tested under cavity boiling conditions, which is achieved when the channel is installed in the PV-2 experimental loop [2]. The operating parameters of the experimental channel under boiling conditions are shown below: Pressure, kg/cm2 130 Water temperature at inlet, ?C 250 Coolant flow rate, t/h 1.2 Channel power, kW 170 Steam content on exit from channel, To 7 Maximum temperature of outer fuel element cladding, ?C 470 Tests of the channels under cavity boiling conditions were conducted with a steam content at the out- let of up to 7% by weight, which corresponded to the target of the experiment. The main part of the experimental dual-fuel-element channels (see Table 1) was loaded into the reac- tor of the world's first nuclear power station in 1970. It can be seen from Table 1 that the fuel burnup in the fuel elements, the greater heat flows and the higher temperatures of the fuel element claddings confirm the operation of the experimental channels in more rigorous conditions by comparison with the standard fuel channels. The dual-fuel-element channels have operated in the reactor for about four years and are continuing to be used up to now. At present, fuel elements with heat exchange intensifiers are being tested in the experimental channels, with increased diameters and with a greater fuel charge. LITERATURE CITED 1. G. N. Ushakov, The First Nuclear Power Station [in Russian], Gosenergoizdat, Moscow ? Leningrad (1959). 2. Ten Years of the World's First Nuclear Power Station, SSSR [in Russian], Atomizdat, Moscow (1964). 869 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 STATISTICAL CHARACTERISTICS OF THE TEMPERATURE FLUCTUATIONS IN A DIRECT-FLOW SODIUM? WATER STEAM GENERATOR B. V. Kebadze, V. S. Sroelov, UDC 621.039.534.63:621.039.534 B. V. Kul'pin,* and A. I, Gavrilin The temperature fluctuations in heat-transfer systems produce thermal stresses and fatigue damage on prolonged operation. Considerable temperature fluctuations can arise in steam boilers at the start of the zone of deteriorating heat transfer on account of the alternating contact with liquid and steam [1]. The turbulent flow of the heat carrier in the presence of a considerable temperature gradient also produces temperature fluctuations which penetrate into the wall [2]. Finally, temperature fluctuations can also arise to some extent on account of the stochastic nature of the boiling, with random production and detachment of bubbles at the heated surface. Although there have been several studies of temperature fluctuations, it is not at present possible to estimate in advance the magnitude of the fluctuations for a particular apparatus, mainly on account of the difficulty of incorporating thermal and hydraulic characteristics of any particular design. The basic purpose of statistical experiments is to determine the sources of the pulsations, the am- plitude characteristics, and the characteristic times. The measurements were made with a model of a steam boiler using two standard modules made in Czechoslovakia. The body was 159 x 7 m and length 6 m, which contained 19 tubes of diameter 8 x 3, which were fixed in double tubular assemblies. The thermal power of the testbed was 600 kW, but this did not allow us to produce normal mass flow speeds for the water in the 19-tube module. We therefore left only six working tubes, which lay at the edge of the tube bundle. The other tubes were blanked off and served for monitoring purposes. This enabled us to make measure- ments at flow rates in the range 400-850 kg/see-m2, but the sodium speed in the generator was below the nominal value by about a factor of three. The tubes were made of NT8Kh6 steel. We mounted 50 microther- mocouples in stainless-steel jackets of outside diameter 0.5 mm on one working tube at intervals of 190 mm in the evaporator module near the outer surface of the body. The ther- mocouples were contained in longitudinal slots of depth 1 ram i and introduced through the body. In the space between the 134 138 145 150 112 ? Steam tubes of the evaporator module, along an internal generator, there were 17 thermocouples in stainless-steel jackets of 67 outside diameter 0.8 mm. Figure 1 shows the thermocouples used in most of the statistical experiments. The sodium flow rate was measured by an electromagnetic flowmeter calibrated to 2%. The water flow rate was determined from the pressure difference with a standard throttle using a dif- ferential manometer DM of class 1.5. In each working state (Table 1) we measured the tem- perature distribution in the sodium and at the tube wall along the length of the boiler, which went with the input and output parameters of the sodium and water (steam) to provide a Fig. 1. The steam generator with trans- basis for calculating the heat fluxes and heat-transfer coef- ficients, for comparison with theoretical values. =-44111111 111111 170 169 166 167 166 I 11110 1111" Water 113 114 1Na ducers. *Deceased. Translated from Atomnaya Energiya, Vol. 39, No. 4, pp. 250-254, October, 1975. Original article submitted October 3, 1974. ?1976 Plenum Publishing Corporation, 227 West 17th Street, New York, N.Y. 10011. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission of the publisher. A copy of this article is available from the publisher for $15.00. 870 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24 : CIA-RDP10-02196R000400060003-2 1 k L464:- 0,6 4 6 710 2 10-1 100 f, Hz Fig. 2 Fig. 3 Fig. 2. Autocorrelation functions for temperature fluctuations: 1) T138, a = 4?C; 2) T134, g = 1.4?C; 3) T134 ? T145; 4) T167, 0- = 2.4?C; 5) T166 ? T167. Fig. 3. Spectral densities corresponding to the correlation functions of Fig. 2: 1, 2, and 4) as in Fig. 2; 3) modulus of the cross spectral density. In the dynamic experiments, we measured primarily statistical characteristics of the thermocouple signals near the crisis region. We used electronic potentiometer recorders with 2-mV scales to record the temperature fluctuations. The signals were amplified for statistical processing and converted to a pulse-frequency code for magnetic tape recording. This recording was performed simultaneously on 4 channels. Specialized com- puters (correlograph) calculatedthe mathematical expectation, dispersion, and autocorrelation functions, while a digital computer calculated the spectral densities. Pulsations of elevated amplitude occurred near the crisis region, which was first restricted to a length of 200 mm or so. The modes of operation were chosen so that the deviations of the thermocouple signal from the crisis zone to both sides of the mean were approximately equally probable. The pulsations remained stationary for 10-15 min. The precise mode of pulsation away from the crisis zone was less dependent on the working parameters. In all we performed over 30 runs, in which we varied the flow rates, water temperature, pressure, and other parameters. We now consider some typical statistical characteristics. The normalized auto- correlation functions of Figs. 2 and 3 (except for curves 4 and 5) relate to the first mode (Table 1). The mode corresponds to a somewhat larger heat flux in the sections containing thermocouples 166 and 167. Thermocouples 134, 138, 145, and 150 were mounted in the tube, while 166-170 were in the sodium. The crisis zone lay near thermocouple 138. The fluctuations in the crisis zone had a standard deviation of about 40?C and contained considerable damp component with a period of about 2 sec, which was almost ab- sent at adjacent thermocouples. The periodic form of pulsation was observed in many runs. Preliminary analysis showed that the reason may be some features of the water part of the system. For technical reasons, only part of the steam passed through a condenser and cooler, while the rest was mixed with the condensate directly ahead of the pump, which can lead to flow-rate fluctuations and temperature variations in the crisis zone. To test this, the fluctuations in water flow rate were written along with the other sig- nals to the magnetic tape. We analyzed the normalized autocorrelation and cross-correlation functions for the flow rate and temperature in the crisis zone (Fig. 4, second mode, Table 1), and found a high (about 0.5) correlation coefficient, which was determined as R xy Mmaxi X ? V R xx (0) Rim (0) TABLE 1. Working Parameters of Steam Generators GI120, tons/h W0, kg ini2 . sec t 1 14, ?C t 113, ?C GN a, M3 ill tin, ?C t67, cC qi. kcal/m ? h q+ 1. kcal/m .h 1,08 1,25 445 512 252 287 341 333 12,2 9,4 462 508 304 306 41,7 51,4 147 208 Note. Steam pressure 100 atm; qt and qi linear heat fluxes before and after heat-transfer crisis zone. 871 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 R 48 46 0,4 012 0 -42 -44 0 / 1 1 A i 1 1 ? '`....., % ? ?.2 1 1 1 1 2 3 4 5 Fig. 4 Fig. 5 Fig. 4. Autocorrelation functions for temperature fluctuations and water flow rate: 1) T138, a = 6.3?C; 2) GB, a = 0.6%; 3) T138 ? GB. Fig. 5. Distributions for the temperature fluctuations: 0) T138; e) T134; normal distribution. as well as agreement between the periods and time shifts in the peak for the cross-correlation function, which indicates delay in the temperature with respect to the flow-rate variation. One can say that the lat- ter variation is the external factor determining the character of the temperature pulsations. The measured relative standard deviations in the flow rate were small (maximal value about 1.2% in all runs), but the tem- perature fluctuations in the crisis zone became considerable (a = 9?C), which corresponds to a doubled fluctuation amplitude of about 25?C. The amplitude of the temperature fluctuations increased as the fre- quency was reduced and as the amplitude of the flow-rate fluctuations increased. The temperature fluc- tuations in the crisis zone were anharmonic, as is clear from the content of higher harmonics in the spec- tral density (curve 1 of Fig. 3). The distributions (thermocouple 138, Fig. 5) differ substantially from normal, whereas the distribution for thermocouples outside the crisis zone was closely normal (thermo- couple 134, Fig. 5). The fluctuations in the thermocouple signals away from the crisis zone contained low-frequency and high-frequency components (curve 2 of Fig. 2). The periodic component was weak even when the water flow-rate fluctuations were present, for quite obvious reasons. The coefficient of heat transfer from the steam to the tube was low in the region of deteriorating heat transfer, and the thermocouple in the wall perceived in the main the fluctuations on the sodium side, whereas the thermocouple monitoring the steam at the output produced a periodic component correlated with the flow rate. In the section before the crisis region, the temperature in the tube was only slightly dependent on the flow-rate fluctuations. We also used cross-correlation methods to detect the source of the temperature fluctuations in the tube away from the crisis zone. Figure 2 (curve 3) shows the cross-correlation function for thermocouples 134 and 145, which lie one on each side of the crisis zone; this contains almost solely a time-of-flight component, whose time shift agrees satisfactorily with the calculated transit time for sodium in that sec- tion. The same applies to the cross-correlation function for series of thermocouples in sodium (curve 5 of Fig. 2). Here the spectrum of the fluctuations was wider than that for the thermocouples in the tube (curve 4 of Fig. 2 and 3). In measurements on the statistical characteristics of the sodium thermocouples it was found that the dispersion decreased away from the sodium inlet, and hence it was much lower in the lower part of the module. On the other hand, there was a marked rise in the dispersion on passing through the crisis re- gion from the zone of deteriorating heat transfer to the region of dispersed annular flow, with the heat flux increasing by about a factor 4. The standard deviations for sodium thermocouples 166, 167, 169, and 170 were 3.3, 3.0, 1.9, and 4.2?C, respectively,when the crisis zone lay between thermocouples 169 and 170. The relatively high-frequency fluctuations recorded by the thermocouples in the sodium and in the tube walls are due to motion of hydrodynamic nonuniformities of eddy type in the transverse temperature gradient. The strength of the eddies is particularly high where there is a destabilized flow near perturba- tion source (here the sodium inlet). The heat flux in the section between thermocouples 166 and 169 alters 872 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 -t. 2' 3 4 5 q ? 10-5, kcal/(m3.h) Fig. 6 Fig. 7 Fig. 6. Standard deviation of temperature fluctuations in sodium as a function of heat flux for Re =const=25,000: X) T167; 0) T169; 0) T170; A) Tim; A) T180. Fig. 7. Correlation functions for the thermocouples in one cross section: T166 ? T150. only slightly, and the decreased amplitude of the temperature fluctuations is due to damping of the hydro- dynamic perturbation away from the sodium inlet. The increased pulsation near thermocouple 170 is due to the discontinuity in the heat flux. The sodium flow rate varied only slightly under the various conditions. The standard deviation of the temperature in the sodium as a function of heat flux is roughly of straight- line type (Fig. 6) for several thermocouples, and the fluctuations are larger for couples closer to the so- dium inlet. Figure 7 shows the cross-correlation function for thermocouples in the same cross-section at diamet- rically opposite edges of the body (in the sodium and tube). The sharp fall to negative values for small time shifts indicates that there are eddies comparable with the geometrical size of the steam-generator body (Dgeom)? The large eddy size also explains the high correlation coefficient (0.4-0.5) for the thermocouples separated by a considerable distance along the axis (L/Dgeom > 10). Then the temperature fluctuations in the wall in the crisis zone are largely determined by the flow- rate fluctuations; fluctuations in flow rate very minor from the operating viewpoint (about 1%) can result in temperature fluctuations of doubled amplitude up to 20-30?C. More detailed studies could be made of the relation between the flow-rate fluctuation and temperature fluctuation on a one-tube model. Another appreciable source of temperature fluctuations lies in the large-scale eddies, which migrate in parts of destabilized flow due to the transverse temperature gradient. It is difficult to predict the exact extent of the fluctuations on a full-scale model on account of the differences in the temperature gradients and the hydrodynamic perturbations, but one should bear in mind that the level of the latter increases ra- pidly with the sodium flow rate. To reduce the importance of such fluctuations, one should avoid elevated temperature differences at parts where the flow is destabilized. In the present design, the zone of transi- tion from deteriorating heat transfer to dispersed annular flow should be as far as possible from the so- dium inlet. LITERATURE CITED 1. V. A. Vorob'ev et al., in: Exchange of Accumulated Experience on the Design and Commissioning of Fast-Reactor Systems Based on the BOR-60 Reactor [in Russian], Izd. NIIAR, Dmitrovgrad (1973), p. 266. 2. M. Kh. Ibragimov, V. I. Merkulov, and V. I. Subbotin, in: Liquid Metals [in Russian], Atomizdat, Moscow (1967), p. 71. 873 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000400060003-2 ANALYSIS OF THE CONDITIONS REQUIRED FOR PRODUCING HIGHLY PURIFIED CARBIDE FUEL BY REDUCING OXIDES WITH CARBON, AND STUDY OF THE BEHAVIOR OF OXYGEN AND CARBON IMPURITIES IN THE PRESENCE OF FISSION PRODUCTS R. B. Kotel'nikov, V. S. Belevantsev, S. N. Bashlykov, G. V. Titov, V. A. Zelyanin, and A. M. Anuchkin UDC 621.039.542.394 The use of carbide fuel in fast reactors is one of several possible ways of achieving high economic efficiency [1, 2]. One of the most promising techniques for producing carbide fuel on an industrial scale is by reducing the oxides with carbon [3-5]. Certain questions associated with the production of carbide fuel by this method and with its subsequent use are still under discussion and require further investigation. This applies, in particular, to the problem of determining the optimum conditions for the production of carbide fuel with the minimum oxygen and carbon contamination and also the behavior of these impurities under conditions of irradiation. A theoretical and experimental determination of the temperature corresponding to the onset of the reaction between uranium and plutonium oxides and carbon [6, 7] failed to produce the necessary agree- ment. We therefore calculated the temperature dependence of the oxygen potential in the U? C-0 system by the Pourbaix method [8] using the latest thermodynamic data (Table 1) and plotted the corresponding diagram (Fig. 1). The free energy of formation of UCi_x0x was calculated from the equation LF =(1 ?x) AFuc ? 4.576T (1 ?x) lg (1 ?x)d- xAFuo + 4.5767'x lg x on the assumption that ideal solid solutions of the UC?UO system were formed. The limiting solubility of oxygen in UC was taken as 17.5 at. % [12]. The minimum reaction temperatures obtained from the Pourbaix diagram for various pressures are given in Table 2, from which we see that the reaction underlying the production of uranium monocarbide by TABLE 1. Thermodynamic Characteristics of Compounds Belonging to the U? C ?0 Sys- tem Compound Equation for AF. Temp- cal/mole range, *K Ref. CO(g) UO2 (0 1.10(g) (s) UC2(s) U2C3(s) UCO .6500 .35(0 ?26 700 ? 20,95 T ?258 000+40,00 T ?258 300+40,50 T ?121 200-h 22,46 T ?24 260-1,12 T ?25 500 ?21 300-3,00T ?22 240-1,96T ?24 250-1,20 T ?58 150+5,83T ?58 950+6,56 T 298-2500 298-1405 1405-2000 298-2500 298-1200 1000-2200 298-2200 1100-1400 1400-2000 298-1200 1000-2200 JZO io-4atm CO-. wozwo 1 atm \ wai;(ici) 6 keV where the influence of resonance screening is small, the ratio of the count rates of the y counter should be constant; this was confirmed by the experiment, and so by using the data from the "thick" specimen we could reduce the sta- tistical scatter in this energy range. Normalization of the data with respect to a was effected with thermalized neutrons in a graphite prism with a gold specimen with n = 1.8.1021 nuclei/cm2 and with a "thin" plutonium specimen for which screening in the thermal flux was small. The measurements with the "thick" specimen were related to the measurements with the "thin" speci- men in the energy range 8 keV < En