ORNL-TM-7207 - the Molten Salt Energy Technologies Web Site

More documents

Recommendations

Info

92 cooled drain tank. The system primary containment, which is defined as the set sf hermetically sealed concrete-shielded equipment cells, would probably not be threatened by such a spill, but cleanup operations would be d5fficult e A unique safety feature of the DMSR is that, under accident shutdown conditions, the fuel material would be led to the emergency core cooling system gECCS> (represented by drain tank cooling) rather than vice versa. The reactor and containment must be designed SO that the decay-heated fuel salt reaches the drain tamk under any credible accident conditions. In any case, the decay heat is associated with a very large mass of fuel salt so that melt-through (or “China Syndrome”) is apparently not a problem. The safety philosophy for accidents involving the reactor core is very different for fluid-fueled than for solid-fueled react~rs because the heat source is mainly in the liquid-fuel salt and not in a solid, which requires csntinuous cooling to avoid melting. An LMFBR, for exam- ple, has a large amount of stored energy (which must be removed under any accident conditions) in the fuel pins. DPy~ut, which means immediate meltdown in an LMFBR, would not be nearly as severe in the DMSR because the heat source is removed along dth the cooling capability. First-order analysis has shsm that a flow blockage of a central coolant channel of the reference DKSR which reduces the flow to less than -20% of nominal will probably result in local voiding of that channel. This was not true of the old MSBR design8 because the channels were more strongly themally coupled. Whether the safety implications of this will lead to modifica- tions of the DMSR reference design must be shorn by future safety analysis studies. Under any off-nsmal conditions, the fuel salt will be chan- neled to the drain tank, which must have reliable systems for decay heat removal. No credible means exists for achieving recrfticality once the fuel salt has left the graphite-moaeratea cores There are no significant differences in the enviromental effects of routine operations between an MSl? and reactors presently in commercial operation. No gaseous or liquid radioactive effluent discharge occurs
93 during noma1 operation. Minor amounts of such effluents way result from maintenance operations involving opening the primary system. The MSR (along with the HTGR and the LMFBR) is in the class of reactors which operates at high temperatures and high thermal efficiencies - about 4QX compared with about 32% for LWRs. For the same electrical ea- pacity, these more efficient reactors reject about 40% less beat to the environment. '%%lis can reduce impacts such as consumptive use of water re- Sources, atmospheric effects, and effects on aquatic life. In the reference DMSR concept, neither the nuclear fuel nor the fis- sion products (except for the vslatiles, including xenon) are removed from the primary system during the reactor lifetime. This eliminates a major environmental problem of present day LWWs: frequent transportation of highly radioactive spent fuel from the reactor site to the reprocessing! storage facility. Most radioactive material remains within the BMSW primary containment for the 30-year reactor lifetime but must be dealt with at end-of-life. Uranium, Eithim, and possibly other valuable elements will probably be recovered for reuse, but the remainder, which contains the actinides americium and curium (not found in significant amounts in spent EWW fuel), will have to be disposed of. Decommissioning the plant way be more difficult than for an EWR because the entire primary circuit will be intensely radioactive. A large amount of tritium is generated in MSRs as a result of neutron reactions with the lithium in the fuel salt. Tritium is to diffuse through metal walls such as heat-exchanger tubes, thus providing a poten- tial route for transport of gaseous trittum through the secondary coolant loop to the steam generators. Recent experiments have shown that tritium is oxidized in the secondary coolant (sodium fluoroborate), which blocks further transport of tritium. The release of tritium from MSRs to the environment is estimated to be no greater than from LWRs and is well within NRC guidelines. A power economy in which the MSR plays an important role would re- quire large quantities of lithium, BeryPlium, fluorine (for the fuel-salt mixture), nickel (which comprises 78% of the Hastelloy-N), and graphite (naode~~to~ elements). The environmental. effects of obtaining, using,, and disposing of these materials would certainly have to be evaluated.
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 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 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: t.;$- ... quite different from thos
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
show all

ORNL-TM-7207 - the Molten Salt Energy Technologies Web Site

Create successful ePaper yourself

Delete template?

Save as template?