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[-SO0 kPa (130 psi)]. analysis were obtained from Ref. 8. 46 Graphite and fuel-salt properties used in the The reference DMSR design satisfies the two most important thermal-hydraulic considerations: (a> the maximum graphite temperature is ISW enough to allow it to last the life of the plant (24-full power years) and (2) regions sf stagnant or laminar flow are avoided. Halay Variations OR this design W i l l be possible in achieving iipl Optimum core, but the second consideration must always be noted. Because of the EQW thermal conductivity of the fuel salt, excessive temperatures can occur in very small stagnant or laminar flow regions. The graphite elements must retain their geometric integrity and must not create flow blockages. Extensive in-pile testing would be necessary to ensure that both of these cOnsideratiOnS Were met before Const?XC%iQn Sf %! d€SXlonStratiOn plant could be undertaken. 3.3 Fuel Behavior Excellent neutron economy is an absolute requirement for a thermal breeder (such as an MSBR), and fuel co~lponents with acceptably low neutron CFQSS sections are few. We recognized very early in the MSBR development effort that (1) only fluorides need to be considered, (2) only LiF and BeP2 would prove acceptable as fuel solvents (diluents) for the fissile and fertile fluorides, and (3) the LiF must be highly enriched in 7Li, For a break-even reactor or for one that, though it retains most of the fission pr~ducts within the fuel, is to be an effective converter, some sacrifice in meutron economy may be permissible. However, no likelihood for success seems possible with diluents other than BeF2 and LiF highly enriched (probably to 99.99%) in 'Li, Accordi~gly, the fuel system for a DMSR necessarily will be very similar to the system that received intensive study for many years in MSBR development. A considerable fund of information exists about ckem- ical properties, physical properties, and expected in-reactor behavior of suck materials.
.... ... . ....... . .%.W 3.3.1.1 Composition of DMSR fuel 47 3.3-1 Basic considerations Choice of initial composition. A DMSR will derive some of its fission energy from plutonium isotopes, but 2 3 3 ~ and '3% will be the primary fissile isotopes, while '32~h, with important assistance from 2 48~, is the fertile material a concentration will need to be markedly higher than the total concentration of uranium isotopes. Clearly (see previous neutronics discussion) the 232~h The only stable fluoride of thorium is ThF4; thus, it must be used in such fuels. Puke UF3 is appreciably disproportionated at high temperatures by the reaction Generally in molten fluoride s~lutions, this reaction proceeds appreciably at lower temperatures. fuel by reaction (reduction) of UP4 with species within the container metal and, as explained below, a small quantity of UF3 deliberately main- tained in the fuel serves as a very useful reduction-oxidation (redox) buffer in the fuel. Such UF3 is sufficiently stable in the presence sf a large excess of UP,, but UF4 must be the major uranium species in the fuel. 19320 also by LE,), and PuF3 is the stable fluoride of this element in DMSR fuels. A small amount of UF3 will be formed within the ~onversely, PUF~ is reduced by the metallic container (and Phase equilibria among the pertinent fluorides have been defined in detail and are well documented. 19-21 Because the concentration of ThF4 is much higher than that of UF4, the phase behavior of the fuel is dic- tated by that of the LiP-BeF2-ThF4 system shown in Pig. 11. 3LIP*ThF4 can incorporate Be2* ions in both interstitial and substitu- tional sites t o form solid solutions whose compositional extremes are rep- resented by the shaded triangular region near that compound. The maximum ThF4 concentration available with the liquidus temperature below 500°C is just above 14 mole %. Replacement of a moderate amount of ThP4 by UF4 scarcely changes the phase behavior. The compound
Page 1: i *w . . I
Page 5 and 6: P iii CONTENTS ....................
Page 7 and 8: CONCEPTUAL DESIGN CHARACTERISTICS O
Page 9 and 10: 3 The primary purpose of this study
Page 11 and 12: .. .... . w..w c Y ... . r 5 2. GEN
Page 13 and 14: ii.... :.: ..... .,. \ ..... %& . 3
Page 15 and 16: addition StathQR would be required.
Page 17 and 18: !I \.... . , . ~ .... .. . . / I I
Page 19 and 20: ... .. ...... . . . $i 13 Table 1.
Page 21 and 22: 15 Initial scoping studies showed t
Page 23 and 24: .. . E 6> I S N 0.45 k- 0.50 B --.
Page 25 and 26: :.:..y ,. . . w, E9 The code calcul
Page 27 and 28: h 3. Additional 238Y is added as re
Page 29 and 30: ...z,y .. . c .A, Table 9. Actinide
Page 31 and 32: ';x.w' .... Relative power distribu
Page 33 and 34: ........ . . . :..i 27 a Inner 2.54
Page 35 and 36: 29 Table 16. Effect of neutron spec
Page 37 and 38: ob E 2 a 4 5 6 7 8 9 10 11 12 13 14
Page 39 and 40: .. . . . . . . . . . 'a# 0.1 0.2 0.
Page 41 and 42: 35 (Doppler effect), (2) changing t
Page 43 and 44: where Ci = relative delayed-neutron
Page 45 and 46: .... . . . . , c.y..p c "
Page 47 and 48: .... :...w . . . . . :, %. , dimens
Page 49 and 50: ,. ::.y ~. . .... , 40 0 43 1 2 3 4
Page 51: .,.,. . . ., , .. . . . . . . . %..
Page 55 and 56: 49 Variation of fuel composition wi
Page 57 and 58: .. .*,p. . . . . . . . Table 25. Ph
Page 59 and 60: ;: c.... x. . w ..i 53 Table 26, St
Page 61 and 62: would be expected to have an equili
Page 63 and 64: .... . . . . :i ,.*,&s 57 Corrosion
Page 65 and 66: . ;;..,..I . . . . . . "LW 0 9 m -
Page 67 and 68: of the fissioned atom. ea ~arly ass
Page 69 and 70: 63 n e results of a program of solu
Page 71 and 72: 65 Table 27. Sources and rates Sf p
Page 73 and 74: operation of the PISRE. 67 analyses
Page 75 and 76: UP3/UF4 ratio would be possible. DM
Page 77 and 78: $ .p9 3.3.3.1 Preparation of initia
Page 79 and 80: 73 Contamination of fuel by seconda
Page 81 and 82: *w- through the walls of the primar
Page 83 and 84: 77 4 will apparently be necessary (
Page 85 and 86: such contamination. For a demonstra
Page 87 and 88: 8% 3.4 Reactor Materials Although s
Page 89 and 90: : ....., . .’ -. ..WY used in the
Page 91 and 92: ..... i.. ....., . .Yd 85 QRPIL-DWG
Page 93 and 94: ... w . . .y and to salt containing
Page 95 and 96: With the different ~Bjectives of ns
Page 97 and 98: t.;$- ... quite different from thos
Page 99 and 100: 93 during noma1 operation. Minor am
Page 101 and 102: ............. . . .. . .=w as SSm,
Page 103 and 104:
. . . :.w . . . . , 4. ALTERNATIVE
Page 105 and 106:
.. . ... . . . . . . .. . . "W 3. T
Page 107 and 108:
.,.. w .." by removing some uranium
Page 109 and 110:
, . . . . . . , -c%w probably still
Page 111 and 112:
and the ~ dvent (or carrier) salt a
Page 113 and 114:
BO 7 TPle fuel makeup requirements
Page 115 and 116:
5. CQPIPIERCIWLPZATION CONSIDERATIO
Page 117 and 118:
11% At the close of MSRE operation,
Page 119 and 120:
12YS 75 22”” 955 30” 1””
Page 121 and 122:
115
Page 123 and 124:
aa 7 some components in common with
Page 125 and 126:
Ae eo un t No * Table 3%. Capital c
Page 127 and 128:
- ,.,.,.,., p .. ..... . G is based
Page 129 and 130:
123 Table 34. Summary of annual non
Page 131 and 132:
...... . . . . ., x.:w* 4 i.. ... _
Page 133 and 134:
E2 7 There are no detailed estimate
Page 135 and 136:
129 particularly if such activities
Page 137 and 138:
. ~.........* . . . . . :*. ... . -
Page 139 and 140:
. .. . . . . . . . ;.:w b 133 the i
Page 141 and 142:
_... ..&/ ; .; with reactor scram m
Page 143 and 144:
137 includlng $900 million for the
Page 145 and 146:
139 The authors want to acknowledge
Page 147 and 148:
. ... . .,.,.,.,.,. . , i.rc- q....
Page 149 and 150:
.:. _.i .. ..... -.=* 45. A. L. Mat
Page 151 and 152:
...... &;.& 3 14 5 74. W, R. Grimes
Page 153 and 154:
p 103. 6. Re Hudson 11, CQNCEPT-5 U
Page 155:
... . . . . . . . , . ,.Y&fl 149 ap
Page 158 and 159:
Account No. -0- Three- digit digit
Page 160 and 161:
.... ..
Page 162:
156 77. He 6. MacPherson, Institute
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