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surface. 72 Outgassing sf the moderator by pumping at reduces pressure and elevated temperature is necessary and sufficient to prevent contamination of the fuel by oxide ion from reactive gases from this source. Oxide films on the structural metal can also contaminate the fuel by oxide ion, and, as described previously, the dissolved ~e3+$ ~e2+$ and Ni2+ can be responsible for subsequent metal corr~sion. In operation sf the MSRE, the system was flushed with an LiF-BeF2 mixture for cleaning at start-up and after each shutdown before introduction of the fuel mixture. This precaution might be unnecessa%y, but it did suffice to keep oxide contamination caused by surface oxidation of the metal to a minimum. A small (-1OO-ppm) concentration of ~r2+ in the fuel as a consequence Of reaction Of the metal with the fuel Cartnot be aVOid@di. However, in the absence of extraneous oxidants, the reacti~n is very slight, and the pres- ence Of Cr2' is CQIIIpbet@%y illlX3CuOuS. Grow-in of the fission products is also unavoidable, as is the pres- ence of a relatively small steady-state concentration of 3 ~ ~ . Atmsspherfc contamination. Reaction of the DMSK fuel mixture with * oxygen is relatively slow, but reaction with water vapor is more rapid, Further, contaminati~n of the fuel with 40 to 50 ppm (by weight) sf oxide ion could result in precipitation of a uranium-rich (UTB%)02 solid SO~U- tion, A large ingress of contaminant air would be re~taired to produce 40 ppm Of 02- in the fuel, and the DMSR would be designed amd operated SO as to minimize the chances sf such contamination. Operation of PISRE during much Of a fQuK'-yeaaP period With Illany ShUtdOWTls and several lrnimpor repair opera%ions sho~ed no evidence sf an increase in oxide contamination level.22 ~reatment the initial fuel charge with anhydrous HF-B~ mixture during its prepratton reataces the 02- concentration to innocuous Peve%s, and similar treatment of contaminated fuel would serve to re~~ve the o%-. such treatment might never be required, but in the DMSR, simple equipment should be included that is capable of treatment to ~emove oxide fOn should BnadVePtent CoRtPARinatiOn BCCUre dr KQW~V~P, the reactor metal at high temperature can readily react with oxygenB and the fuel can react with the oxides formed in this mannero .... . . . : . wx
73 Contamination of fuel by secondary coolant. The only secondary coolant that has been demonstrated in a molten-salt reactor is Li2BeF4, which is prepared from 7%iF and purified through procedures described previously ~QI- the fuel in the MSRE.~~ mis material is not considered suitable for an MSBR or a DMSR because it is expensive and its liquidus is too high. Many substitutes have been considered, bur none have properties that are all near the ideal. Bat balance, the best choice appears to be a mixture of 8 mole X NaF and 92 mole 2 %9aBF4 (Refs. 19, 20, and 88). These compounds are readily available at Isw cost. The liq~idus~~ (see F%g. 151% stability toward gamma radiation in the primary heat exchanger,9Q heat-transfer properties $23 $24 391 and compatibility47 948 with modified HasteEBoy-W all appear adequate. Intermixing of the fuel and the secondary cooIant salts, as caused by leaks in the primary heat exchanger, would be an important considera- tion. ~fae MSBR design8 and presuwa~y the DMSR design assured a slightly higher pressure on the coolant side so that most leaks would be of coolant into fuel. Such a Leak, however small, should be recognized at. once Fig, 15. System NaF-NaBF4.
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i *w . . I
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P iii CONTENTS ....................
Page 7 and 8:
CONCEPTUAL DESIGN CHARACTERISTICS O
Page 9 and 10:
3 The primary purpose of this study
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.. .... . w..w c Y ... . r 5 2. GEN
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ii.... :.: ..... .,. \ ..... %& . 3
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addition StathQR would be required.
Page 17 and 18:
!I \.... . , . ~ .... .. . . / I I
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... .. ...... . . . $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 and 52: .,.,. . . ., , .. . . . . . . . %..
Page 53 and 54: .... ... . ....... . .%.W 3.3.1.1 C
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: $ .p9 3.3.3.1 Preparation of initia
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.. ... _
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E2 7 There are no detailed estimate
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129 particularly if such activities
Page 137 and 138:
. ~.........* . . . . . :*. ... . -
Page 139 and 140:
. .. . . . . . . . ;.:w b 133 the i
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_... ..&/ ; .; with reactor scram m
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137 includlng $900 million for the
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139 The authors want to acknowledge
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. ... . .,.,.,.,.,. . , i.rc- q....
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.:. _.i .. ..... -.=* 45. A. L. Mat
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...... &;.& 3 14 5 74. W, R. Grimes
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p 103. 6. Re Hudson 11, CQNCEPT-5 U
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... . . . . . . . , . ,.Y&fl 149 ap
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Account No. -0- Three- digit digit
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.... ..
Page 162:
156 77. He 6. MacPherson, Institute
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