v} ¢ .." RECEIVED BY DTIE JUL 231969 -~y OAK RIDGE NATIONAL LABORATORY operated by UNION CARBIDE CORPORATION w NUCLEAR DIVISION for the U.S. ATOMIC ENERGY COMMISSION ORNL- TM-259¢6 Copy No. - ~33 Date - July, 8, 1969 FRACTIONAL CRYSTALLIZATTON REACTIONS IN THE SYSTEM LiF-BeF,-ThF, R. E. Thoma and J. E. Riccil ABSTRACT Equilibrium and non-equilibrium crystallization reactions in the system LiF-BeF,-ThF, are analyzed in relation to their potential application to molten salt reactor fuel reprocessing. Heterogeneous equilibria in the temperature range from the liquidus at 590°C to the solidus at 350°0C are described quantitatively and in detail by means of ten typical isothermal sections and by three temperature-composition sections. The implications of metastable fractionatiom-~in this temperature interval are discussed as & possible feed control step in reductive extraction reprocessing of molten salt breeder reactor fuels. NOTICE This document contains information of a preliminary nature and was prepared primarily for internal use at the Oak Ridge National Laboratory. It is subject to revision or correction and therefore does not represent a final report. QEIRIBUTION 08 TS SOCTIAIR & IRTHITE This report wos prepored as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on beholf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatys, method, or process disclosed in this report may not infringe privotely owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, ‘‘person octing on behalf of the Commission’' includes any employee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employse of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor. e e oo LEGAL NOTICE - om o o e oo e sy - CONTENTS Abstract P Introduction v . . . Liguid-Soli id Phase Reactions In The System L m LiF-BeF,-ThF 4 - . a2 LEGAL NO TICE This yeport WRE prepared a8 an account of Governtasnl aponaoud work. Neithel the United States, nor e Commission, nor AnY parson Acling on Lebalf of the Commission: A. Makes an¥ warranty oT represeuuuon, expressed of jraplied, with respect to the RCOU~ racy, completeness, oF usefulness of 1he information eonumed in this Teport, O that the use of aay {nformatien, apparatus, method, ot process Alaclosed in thid report may oot infringe privately owned rights; oF B. Assumes any Javilities with reapoct to the use of, or for damages resulting from the uge of any information, apparatus, method, or process discioped In this report. As used in the above, ‘'perscen acting on bebaif of the Commission’ jnoludes eny €m= pioyee of contractor of the Commliaszon: or smployee of such contractor, to the oxteut that guch employse or coniractor of the Commission, oF employee of such contracior prepares, d;uscmlnatei. or prqvlde. access 1o, any ipformation pur suant w0 nie emp&oyment or contract with the Commigsiom oF nig employ ment with Buch contracior. INTRODUCTION The ORNL Molten Salt Reactor Program is devoted to the development of molten salt breeder reactors which employ mixtures of molten fluorides as core fluids. Until recently, the most promising approach to the development of molten salt breeder reactors appeared to be a two- region reactor with fissile and fertile materials in separate fuel and blanket streams. Thorium would be carried in the blanket salt, in a salt stream which would consist of a 'LiF-BeF,-ThF, mixture. Advances in chemical reprocessing have provided evidence recently that 233pg and possibly the rare earth fission products can be separated from mixed thorivm-uranium salt by reductive extraction methods employing liquid bismuth. This development, along with other design developments, makes possible a single-fluid breeder reactor, one which has greater simplicity and reliability than the two-fluid reactor. The fuel for the single fluid reactor would be composed of 7LiF, BeF,, Th¥,, and 233U’F4, and might be expected to contain ~ 12 mole ¢ ThF,. Optimization of the 7LiF and BeF, concentrations is not complete, because the trade-off values of several significant factors have not yet been established. These include selection limitations imposed by the equilibrium phase behavior of the LiF-BeF,-ThF, system (°>3UF, concentration will be only 0.2 mole %, and is therefore of little conseguence in this connection), physical properties such as viscosity, vapor pressure, thermal conductivity, and the relations of LiF-BeF,;-ThF, composition to the development of chemical processes for removal of protactinium and the lanthanides. Effective separation of the rare earth fission products from fluoride salt streams which contain thorium fluoride is the keystone to development of semi-continuous reprocessing in single-fluid molten salt reactors. Several methods for reprocessing spent LiF-BeF,-ThF,-UF, fuels are currently under investigation. The method which is regarded as most tractable for engineering development involves the selective chemical re- duction of the various components into liguid bismuth solutions. at about 6009¢, utilizing multistage countercurrent extraction operations. The current status of engineering development of this process has been described by Whatley et a1.2 The initigl steps remove uranium and. protactinium by reductive extraction.3 A strong incentive then exists to remove the rare-earth fission products from the remaining salt. The most nearly feasible approach to this separation seems to be their extraction into bismuth alloy,3 even though the recycle volumes of extractant are marginally acceptable. The efficiency of this separation step would be greatly enhanced if the concentration of the rare earths in the salt mixture were increased by at least tenfold, and if the residual salt solutions were of a much lower concentration of thorium fluoride. That the LiF-BeF,-ThF, phase diagram4 shows the occurrence of low melting mixtures of low thorium fluoride content which are producible from MSBR single-core fluids by metastable crystallization has suggested the possibility that non-equilibrium fractionation reactions might be exploited as a feed control step in the reductive extraction process. Because of its relative complexity, the unpublished version of the LiF-BeF,-ThF, phase diagram may experience less frequent or less effective application in molten salt reactor technoclogy than is warranted by the developments cited above. We therefore describe in thig report further detailed aspects of equilibrium and non-equilibrium behavior in the system. LIQUID-SOLID PHASE REACTIONS IN THE SYSTEM LiF-BeF,-Thl, Methods for interpreting polythermal and isothermal phase diagrams are described extensively in an earlier report5 where the phase relation- ships in a number of fluoride systems were agnalyzed in detail. Interpre- tation of the equilibrium behavior in the system LiF—Bng-ThF44 (Figure 1) iy somevhat more complex than for the systems analyzed because of the occurrence of an unusual solid solution which is produced as the compound 3LiF.ThF,; crystallizes from LiF-BeF,-ThF, melts. The crystal phase of nominal composition, 3LiF.ThF,, precipitates as a ternary solid solution which, at its maximum in composition variability (near the solidus), is described by a composition triangle with apices at LiF-Th¥F, (75-25 mole %), LiF-BeF,-ThF, (58-16-26 mole %), and LiF-BeF,-ThF, (59-20-21 mole %). Two substitution models may provide an explanation for the single phase solid solution area: (1) a substitution of one Be*" ion for a Li+ ion with the simultaneous formation of a 'I‘h4+ vacancy for every four Be2+ ions substituted for Li+ ions to provide electroneutrality and (2) substitution of a single Bt ion for a Li® ion with the simultaneous + formation of a Li vacaney. Model (1) would afford a solid solution ORNL-LR-DWG 37420AR6 The, 1114 TEMPERATURE IN °C COMPQSITION IN mole T - LiF'4ThF4 LiF-ThF, S LiF-2ThE, 3LiF-ThE, ss- 448 4 433 LiF -2ThF; N \/ A/ ~ 848 2LiF-BeF; 5001450 400 | 400 450 500 P as8 £ 360 Fig. 1. Polythermal Projection of the LiF-BeF,-ThF, Equilibrium Phase Diggram. limit in good agreement with the leg of the triangular area with the lesser ThF, content wheregs model (2) would give a line extending from 3LiF.ThF, toward BeF,-ThF,; (60-40 mole ¢). This is a 1limiting line vhich permits considerably higher ThF, content than that found experi- mentally. Accordingly, it appears that both models are simultaneocusly applicablé for the crystallization behavior of 3LiF-ThF, as it crystallizes from LiF-BeF,-ThF, melts. Once the crystal structure of 3LiF.ThF, has been established (a study of the structure is currently in progress6) it will be possible to appraise the validity of these models. Application of ternary phase diagrams to technology often requires a knowledge of the identitiies and compositions of the various phases in equilibrium at specific tempergtures. ©Such information is represented by equilibrium phase diagrams. Typically, phase diagrams of ternary systems are presented as projections of temperature-composition prisms on their basal planes. When such schematic representation includes liquidus temperatures, equilibrium crystallizafion and melting reactions can be described in a quantitative manner. Here, the use of isothermal sections is often valuable, particularly if the phase diagram is complex,. The chief feature of the isothermal section is that it provides informa- tion both about the identity and relative masses of coexisting phases. The crystallization behavior of the 3LiF.ThF, ternary solid solution determines the composition sequence as LiF-BeF,-ThF, melts are cooled. A series of equilibrium isotherms is shown in Figs. 2 to 11, which describe all the equilibrium reactions in the temperature interval from 590°C to 350°C, i.e., the liquidus-solidus interval of chief relevance to the compositions which are likely to have application in molten salt reactor technology, and in which all 3LiF.ThF, solid solution melting- freezing reactions occur. Within this interval all the solid phases of the system are involved. The equilibrium behavior of chief importance to us is described further by the temperature-composition sections, 3LiF.ThF,-2LiF-BeF,, LiF.-ThF,-2LiF-BeF;, and LiF-2ThF,-2LiF-BeF,, shown in Figs. 12-14 (schematic, not to scale). ORNL-DWG 68-11676R ThF, 111 . , TEMPERATURE IN °C LiF+ 2ThFy LiF * 4ThE, COMPOSITION IN mole % 590°C LiF - 2ThE, 2LiF-BeF,” LIF-ThE, P 597 £ 568 3LiF - ThE, £ 565 5 %0 550 £ 526 LiF BeF, 848 2|_iF-BeF2/5aof450 4001 400 450 500 555 P 458 £ 360 Fig. 2. Isothermal Section of the System LiF-BeF,-ThF, at 590°¢. ORNL-DWG 68-11678R Thig 1141 TEMPERATURE IN °C COMPOSITION IN mole % T=570°C 2L1F-BeF2 LiF - ThE, £ 568 3LiF * Thi, £ 565 S00 950 F 526 848 2LiF +BeFs 500?450 400 400 450 500 555 P 458 £ 360 Fig. 3. Isothermal Section of the System LiF-BeF,-ThF, at 570°C. ORNL - DWG 68-{1679R ThE, 111t LiF+ 2ThF, LiF - Thiy LiF - 4ThE, 3LiF * ThFy ss TEMPERATURE IN °C COMPOSITION IN mole % LiF LiF +2Th, 562°C LiF « Thi 3LiF ThE, 950 E£526 848 oLiF -BeF, 500]450 400| 400 450 500 555 P 458 £ 360 Fig. 4. Isothermal Section of the System LiF-BeF,-ThF, at 562°C. 0T ORNL-DWG 68-11677R2 ThF; 1144 LiF * 2ThF, , TEMPERATURE IN °C LiF - 4Thf, COMPOSITION IN mole % ~490°C LiF +2ThF, 2LiF *BeF, LiF * Thi, 3LiF - Th, L.iF e BeFa 848 2LiF°BeF2/ 1450 400| 400 450 555 P 458 £ 360 Fig. 5. Isothermal Section of the System LiF-BeF,-ThF, at 490°C. 1T ORNL - DWG 68-11680R2 ThE, 1111 LiF « 4Thi, TEMPERATURE IN °C COMPOSITION IN mole % Lif *2ThR, ) 457°C LiF « ThE; 3LiF + ThE, LiF . - J BeF, 848 2LiF - BeF; 400] 400 450 555 £ 360 Fig. 6. Isothermal Section of the System LiF-BeF,-ThF, at 457°¢., ¢t ORNL-DWG 68-11675R ThE, #H TEMPERATURE IN °C COMPOSITION IN mole % 447°C LiF « 4ThE, & LiF - 2ThF, £ LiF - Thi, ///' // N \/ — /> \/ : _ 2LiF - BeF; 55 LiF 848 Fig. 7. Isothermal Section of the System LiF-BeF,-ThF, at 447°C. £T ORNL -DWG 69 ~5297 They 11 TEMPERATURE IN °C COMPOSITION IN mole % 440°C LiF - 4ThF, & LiF « 2ThE, /N \J LiF - ThE, 3LiF - ThE; l;'// . ; 7 \/ B\ . L - LiF & = 848 2LiF - BeF; 55 Fig. 8. Isothermal Section of the System LiF-BeF,-ThF, at 440°0C. 1 ORNL-DWG 68-11674 ThE, 1119 TEMPERATURE IN °C COMPOSITION IN mole % 430°C LiF + 4ThE, LiF «2ThF, LiF - Thiy 848 2LiF - BeF2 555 Fig. 9. Isothermal Section of the System LiF-BeF,-ThF, at 430°C. T ORNL-DWG 68-11673 Thi 1111 TEMPERATURE IN °C COMPOSITION IN mole % 358°C LiF < 4ThF, LiF * 2ThF, LiF- an-;,, /’7 Y 848 2L|F BeFy— 500 555 Fig. 10. Isothermal Section of the System LiF-BeF,-ThF, at 430°C. 91 ORNL-DWG 68-11672 ThF, 1111 TEMPERATURE IN °C COMPOSITION IN mole % 350°C LiF: 4ThF, LiF - 2ThF, LiF+ Thi 3LiF-ThF, / / - BeFa 848 2LiF-BeFy 555 Fig. 11. Isothermal Section of the System LiF-BeF,-ThF, at 350°C. LT 18 The isothermal sections included in Figs. 2 to 11 are drawn to scale and represent the experimental results which were the basis of the previously published phase diza.g;f,rz_a,:n.‘4 Composition-temperature relations in the LiF-BeF,-ThF, system for LiF concentrations greater than 50 mole % are shown in detail in Fig. 15. The straight lines appearing in Figs. 2 to 1l are tie-lines (or "eonodes") connecting two phases which are in equilibrium. In Fig. 16, point P, as a point on such a tie-line joining points b and z, represents a mixture of the phases (or compositions) b and z with the mole fraction of b equal to the ratio of line lengths zP/zb. In the case of a mixture of three phases, such as the points a, b, ¢ making up the total composition at point P (Fig. 16), the relative amounts of the phases a, b, ¢ making up P may be determined as follows, with the three fractions defined as x of a, y of b, 1l-x-y of ¢. Then: (1) Graphically: extend the line bP to fix the point z on the line ac. Then y = zP/zb, and x = (zc/ac) (1-y). (2) Analytically: 1let the fractions of the components A and B at each of the four points (a, b, ¢, P) be Aa Ab Ac AP’ Ba Bb BC Bp. Then by similar triangles, we hagve B -B B -B a z = "a ¢ = O o NU‘J o td Z Ab_Ap Then BZ = Bb - fiAb + BAZ Ba - Qfla + aAZ Hence A = (Ba - Bb) tBAy - ah B-. 2 7By < By + B Then y =B - B P2z % " B R td I 19 ORNL -DWG 69 - 5294 573 L,B= 2 LiF - BeF, LsT = 3LiF. ThF, 565 ! P - 458° " P."444° LiF UQ+LW+LZB// LyT : 3'ss Lyl +LIF+L B 3 LiF- ThF, | 2 LiF - BeF, (LoT) (L,8) Fig. 12. The Section 3LiF:ThF,-2LiF-BeF, 20 ORNL-DWG 69-5295 LT =Lif - ThF‘ LT, = LiF - 2ThF, LT, = LiF - 4ThF, LzB = 2LiF - BGFZ LIQ + LT, p-762° LiQ LIQ +LT, +LT, LIQ+LT, P-597° LIQ+LT +LT, LIQ+LT LIQ+LT +L,7,, LIQ+L4T, +LiF /LlQ-H_iF P-458° ~=— L1Q +LiF +L,B P-444° LT +L 5T, L10+LaTu ¥t 28 P-433° L3T“”k<\\ L3T33+LZB LiF - ThF, 2LiF - BeF, (L) (L,B) Fig. 13. The Section LiF.ThF,-2LiF.BeF, 21 ORNL—- DWG 69~ 5296 \ LIQ+ThF, LT =LiF - ThF, / LT, = Lif - 2ThF, p_897o ' LT"—' LiF- 4ThF4 LIQ+ThF,+LT, LIQ LIQ+ LT4 P—T762° LIQ+LTeLT, Lch-LTz /LIQ+ LiF P-458° LIQ+LiF+L.B LIQ+ LT 2 LIQ+LT,#LT ““~4JQ+LZB P-448° , - - = - LIQ+LT,+L LA LaTu s LT LIQ +L4T,, 2 31;3 LIQ+L.T +L28 38 P-433° LiF-2ThF, 2LiF-BeF, (LT,) (L,8) Fig. 14. The Section LiF.2ThF,-2LiF-BeF, 22 ORNL-DWG 68-942A TEMPERATURES IN °C LiF « ThF, A& COMPOSITION IN mole % A AVA AVAVA\\VAVAVAVA 0 OO0 NN AN RPN A #Q EWW‘WLWMMM;fihhA /NN NN A 'A NN/ VAV# eV#VAVAVA. A.ammuwfluhdh JAVAVAVAVAVA SOOI NONNNNN AVAVAVA AN SN NN NN ON \VAVAVAVA'T'AV ’\- "A A, VAVAVAVAVAVAYAVAVAY. \VAVAVA \VQVAVAV AVAVA\AV‘VAVAVAVA\.\"VA"VA VA 87 “'6�"% P-SW NN NN NN NN\ AV AN S ™ E-568 N S s o VAVAVA\"WA\‘\VAVAVAV’V‘? v A AN SOV AN IS NN PR N N O *'e'e XN «h-gnwmwmuuh»uhmwg AN SN Wv‘wigww \ (A7 3 AR A A IR I N\ TN\ TN N NTN TN/ AN YL, A NTAVACAY, TN QVA" /T \VAVAVAVA"AVAYAMJAVAVA e AN/ NG A N T PR A AR TR SO N N N DA JWWWWMNUNWhEflflfiaqfiflmmMW\MWV 9 wmmmmmh\«mm»flmmmm@flummmmumWh flh 80 AVAVA\\VAYH\VJA\ LA W NN VNN NN ARG N A AP N/NN NN A nyunwmmgw»wm:mmummmummu'QMMh“mvlew /AR AN \véuv NOAY WA IR RTINS N N NNTNN N NN nh«uuuudnJmummmumb«ummmummmumu§m vmw' NN SN SOV NN NN NRTNRRE SO, '\VAVAVAVAVAVAVA¢ AVAV W/ SARE AVAVAVAVA YAVAVAYA "\, if#“mmwwwwpuflmmmwv4w Amwunmmmmmmanmmmn*A N VN wmnaummum§' NSNS SO KA vm*..'«.nuv NN SN INANT N NN "" TAVAVAVAVAVAY s "AVAVA AVA 5 "A'A AT OR PP OREIRRRE S SIF AR IR A AR A A A ; A AN/ NN NN v"“h\' A/ Y \'Av NN 'AVAVAVA\'\VA'\VAVAVAVAVAV VA 'AVA A Av VA\' o0 LTRSS QOORX XK AL X mwum“ummmmmwummA nuuuumuummgmmwuwmu';mmmuwmmmmmunflflmmw A d@mmmmwmmmunmmsnmm' N AN NSO AN N SRS mh Aamm X vwmwwmmmmmmwmwhnu.ummmmmmrmmnwwnnnm'mflmmummmmu n&'ywk fl§mgmvmnnw1mmruflkwmmm»wmmmmmm;wmmmMfimmmw év e \\AVAVA\'WA\\VA\ QN S\ B IR LN NN AN I NN NN SN, AVAVAVAVAYA' e"’ V VA\'CVAVAVAVAV e N \V AN XY N S TS TN NI "-VAVAVAVAVAVAWVA'AVAVA *unne S SO ¢ dhmn.‘fwmune LIRS IR JAVAVAVAVAY -numn # AN Q PO “WE'AWWNMN‘“WNNMNNMWWNm. muummmwmm@wu nmmmm' nmwummm»wrmmvmmummmgmmmw VAVAVAVAVAVAVAVAN.\WAVAVAVAVAV,A VAVAV IR A R I\ N N i 2LiF*BefF; T P-458 40 A 0 7\VAVAVAVAVAY)” AVAVAN 50E-360 Fig. 15. Phase Diagram of the LiF-BeF,-ThF, System for Compositions 50 - 100 mole % LiF. 23 B , ORNL DWG. 69-7559 A C Fig. 16. Schematic Drawing for Use in Calculating Relative Fractions of Coexisting Phases at Point P. 24 POTENTTAL APPLICATION OF FRACTIONAL CRYSTALLIZATION IN CHEMICAL REPROCESSING Under equilibrium conditions, the crystallization end-point in three component systems such as in the LiF-BeF,-ThF, system, depends on the "compatibility" or three solid phase triangles of the equilibrium diagram. As an example, compositions in the triangle LiF - 3LiF-ThF,- 2LiF+BeF, have their crystallization end-point at the 444°C peritectic reaction point. As noted previously,7 dynamic crystallization of LiF-BeF,-ThF, mixtures does not follow the equilibrium crystallization diagram exactly; instead, non-equilibrium crystallization proceeds characteristically by sub-cooling (i.e., delayed crystallization under dynamic cooling), and by incomplete recombination of liquid and solid phases at the peritectic reaction points. Thus, liquids are produced from mixtures which are of interest to us, primarily those containing high concentrations of LiF, which are richer in BeF,; than their equilibrium counterparts, and which crystallize as described by the lower melting areas of the phase diagram. The consequence of non- equilibrium fractionation is thus to produce liquid residues which are lower in ThF, content than at equilibrium. Let us examine the difference between equilibrium and non-equilibrium crystallization behavior of a liquid composition that would partially typify the reactions of MSBR salts. Suppose the composition ¢, LiF- BeF,-ThF, (63-32-5 mole %), undergoes equilibrium crystallization. On complete solidification, the frozen salt will consist of the three crystalline phases, 3LiF¥-ThF,; ss, 2LiF-BeF,; and Li¥F.2ThF, in proportions given by the position of point ¢ in the correSpénding triangle of Figs. 9, 10, and 11. For non-equilibrium crystgllization this triangle has no signifi- cance. The non-equilibrium process consists of four consecutive steps, seen on the basis of the following diggram: 25 LiF:2ThF, (=D) LiF 2LiF.BeF, (= H) Step (1): freezing starts at ~ 446°C for composition c¢, and the liguid travels on the solid solution liquidus surface to reach curve P; - P3 at some point g (at ~ 440°C), while precipitating some solid solution of composition between a and b, say a' as average. Step (2): 1liquid travels on curve P;-Pi, to reach P; (4339C), vhile precipitating a mixture of solid solution (of composition between b and s, say b' as average) and 2LiF:.BeF,. Step (3): 1liquid travels on curve P;-E, to reach E(356°) while precipitating mixture of LiF.2ThF, + 2LiF-BeF,. Step (4): 1liquid at E(356°) freezes to mixture of LiF:2ThF, + 2LiF.BeF, + BeF,. Quantities involved for 1 mole of starting composition c: 26 Step (1): draw straight line a'c and extend it to curve P;-P,, to fix point g: Moles of liquid reaching £ = a'c = m; a'g Moles of ThF, precipitated (in step 1, or between 446 and 440°) =X, (1-m) = pa, in which X 1 = mole fraction of ThF, at a', etc. Step (2): draw straight line b'-H, and extend straight line gP; back to fix peoint y on line b'-H: 2LiF‘BeF, (=H) 27 - ¥4 Moles of liquid reaching P3 = YPs (m) = my; Moles of ThF, precipitated (in step 2, or between 440° and 433°) = X %?H (my-mp) = ps. Step (3): draw straight line DH and extend straight line P4E back to fix point z on the line DH: Z P 3 | E & LiF 2LiF-BeF, (=H) Moles of liquid reaching E = %%1 (mz) = m3; Moles ThF, precipitated (in step 3, or between 4330 and 3569) =2 (zH 3 (gfi) (m2-m3) = p3, since xp = 2/3. Step (4): moles ThF, precipitated in this step (at 356°) =x, - (P + P2 + p3). Thus, given the original composition ¢ on the phase diagram as we have it, one can meke estimates regarding what happens in steps (1) and (2), and these estimates fix what happens in steps (3) and (4), for the 28 limit of non-equilibrium behavior. This means a process in which there is never any interaction between precipitated solid and solution. Actusl behavior will of course be somewhere between this and the equilibrium process. Since non-equilibrium fractionation of LiF-BeF,-ThF, melts produces final liquids which are low in thorium, and since the concentrations of rare earths in the solutions are expected to be about 20 ppm at the time when fuel processing is economically mandatory, one might anticipate that a semi-zone refining step might well produce and transport liquids of low thorium concentration and containing a relatively high concentration of rare earths (the solubility of the lanthanide trifiluorides in any of the melts one might encounter is almost certainly to be at least 200 ppm at the low temperatures which would be present in this part of the feeder apparatus), The efficiency of this concentration step could possibly be impaired seriously if the rare earth trifluorides either formed intermediate compounds (such compounds are formed only for the lanthanides of 2 63) which interacted with the crystallizing phases or otherwise formed solid solutions with any ‘of the crystallizing phases. The structure of 2LiF-BeF28 and LiF-ThF49 are known and believed to be incapable of serving as solid state hosts for the rare earth fluorides. The 3LiF-.ThF, sclid solution is an unknown factor in this consideration and could conceivably act as a solvent for lanthanide ions. This possibility as well as the possibility that LiF:2ThF, might also serve as a solid state solvent for lanthanide ions could be examined easily through a small scale laboratory program. 8. 29 Consultant, Department of Chemistry, New York University, University Heights, New York. M. E. Whatley et al., Nuclear Applications, fin press). J. H. Shaffer and D. M. Moulton, Reductive Extraction Processing of MSBR Fuels, in Reactor Chemistry Division Annual Report for Period Ending February 28, 1968, ORNL-4396. R. E. Thoma, H. Insley, H. A. Friedman, and C. F. Weaver, J. Phys. Chem. 64, 865 (1960). J. E. Ricci, Guide to the Phase Diagrams of the Fluoride Systems, ORNL-2396, 1958. G. D. Brunton, ORNL, Unpublished work, 1969. C. F. Weaver, R. E. Thoma, H. Insley, and H. A. Friedman, Phase Equilibria in Molten Salt Breeder Reactor Fuels, I. The System LiF-BeF, -[]F'4--ThF4 3 ORNL-2896 s, December, 1960. J. H. Burns and E. K. Gordon, Acta Cryst. 20, 135 (1966). G. D. Brunton, 21, 814 (1964). Coo-JowumddwoH .Ll.td.t"?:fi'w?dfl'ffl:é'}j‘:—ipfflED_EJS:*EDUQ’.IEEUZLIQOHWQWWUMOZgwmmOOU}"—!OWQ!fiQW . Adams . Adamson Affel . Anderson . Apple . Baes Baker Ball Bamberger Barton Bauman . Beall . Beatty . Bell nder . Bettis Bettis Billington . Blanco . Blankenship . Blomeke Blumberg G. Bohlmann J. Borkowski E. Boyd Braunstein O@H@Efit‘d%%t‘*t‘]‘fihtfifiig’fi'fifi@:fi?{ . A, Bredig B. Briggs . R. Bronstein D. Brunton A. Canonico Cantor W. Cardwell L. Carter I. Cathers E. Caton B. Cavin M. Chandler H. Clark R. Cobb k. Cochran W. Collins L. Compere V. Cook H. Cook W. Cooke T. Corbin Cox L. Crowley 31 DISTRIBUTION 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 6l. 62. 63, 64 . 65. 66. 67. 68. 69. 70. 71. 72. 73. 74, 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 8s. 90. ol. 92. 93. 94. 95. 96. 97. 98, 2Hb?dfd.tjfdagf-ipffl?d?:dniiU"'Ut'IJf—IbUWEPZF'LI';U';UQSC—IU.'I!‘AIDL_'Utl:lC—iSHbmflatUU"—lb"-d . Culler Cuneo Dale Davis DeBakker DeVan Ditto Dworkin Dudley Eatherly Engel Epler Ferguson Ferris Fraas . Franzreb Friedman Fry Frye, Jr. Furlong Gabbard Gallsher Gehlbach Gibbons Gilpatrick Grimes Grindell Gunkel . Guymon . Hammond Hannaford Harley Harman Harms Harrill Haubenreich Hebert Helms Herndon Hess . Hightower . Hill Hoffman Holmes Helz . Horton oo - E:TU??:EWWZPFH:.Z.ZMPP??WE;P?JOEbjmeQMZPW*Uth*UKU*UHmHmQQZ . Houtzeel . L, Hudson . R. Huntley 99, 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117, 118. 119. 120. 121. 122. 123. 124 . 125. 126. 127. 128. 129. 130. 131. 132. 133. 134. 135. 136. 137. 138. 139. 140. 141. 142. 143. 144, 145, 146. 147. USUPUZQIT‘EOQUEGDUHOZGSOUQDUE':U’:UE.’PM:DEUKQC—{OQFEHDZ?QCDU%EE}PHO:?A??U:‘U_ZEI! Inouye . Jordan . Kasten Kedl Kelley Kelley Kennedy Kerlin Kerr Keyes Kiplinger Kirslis Koger . Korsmeyer Krakoviak Kress Krewson . Lamb Lane Lawrence Lin Lindguer Litman . Long Lotts . Lundin . Lyon . Macklin . MacPherson . MacPherson Mailen . Manning . Martin . Martin . Mateer Matthews Mauney MeClung McCoy McElroy MeGlothlan McHargue McLain McHNeese . McWherter . Metz . Meyer . Moore . Moulton <§':UUL—'C]I:IJC.')L—'ZHF'L‘*"UUJU)CAPHZUJHmSCD<:C—iPHS'SUC4FEIf-+$U!I1 EL_'CDC-I';UM:DC—IWE"'FIJ.Z::'I: 32 DISTRIBUTION 148. 149. 150. 151. 152. 153. 154. 155. 156. 157. 158. 159. 160. 161. 162. 163. 164 . 165-167. 168. 169. 170. 171. 172. 173. 174. 175. 176. 177. 178. 179. 180. 181. 182. 183. 184. 185. 186. 187. 188. 189. 190. 191. 192-201. 202. 203. 204, 205. 206 . 207. . Mueller . Nichol . Nichols Nicholson Oakes atriarcs Perry Pickel Piper Prince Ragan Redford ichardson Robbins Robertson Robinson Romberger Rosenthal . Ross . Savage . Schaffer . Schilling ap Scott Scott Seagren Sessions Shaffer Sides Skinner Slaughter Smith Smith Smith Smith . Smith piewak Steffy Stone . Strehlow Tallackson . Taylor erry . Thoma Thomason Toth Trauger Unger Watson Watson ot dMrm = PooPRUrEE S QOSZURRNIUQRUQEWEHAP UEEG TS = = e QG NoaHdG=2 26 Ee qmzuwmwzmwwmmHmomwbmzggn;ug NE2EEdgRAEgDY e 208. 209. 210. 211, 212. 213. 214. 215, 216. 217. 218. 219. 220. 221. 222, 223. 224.-225. 226=227. 228-230. 231. 232. 233. 234-235. 236. 237. 238. 239-253. 33 DISTRIBUTION Watts Weaver Wehster Weinberg Weir Werner West Whatley White Wichner Wilson Young C. Young J. P. Young E. L. Youngbhlood F. C. Zapp Central Research Library Document Reference Section Laboratory Records Laboratory Records (LRD-RC) Zarrwamd rb<::UE')F-d.E}"—|L'U3tE"’TJt" al mmt"‘:flf—iZ?i' EXTERNAL DISTRIBUTION C. B. Deering, AEC-OSR A. Giambusso, AEC-Washington T. W. McIntosh, AEC-Washington H. M. Roth, AEC-0ORO M. Shaw, AEC-Washington W. L. Smalley, AEC-ORO Division of Technical Information Extension (DTIE)