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

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CRACKING 600 PARA M E T E W [FREQUENCY ~cm-') x AVG. DEPTH Eptml] ma 0 86 ORNL-DWG 77-4680A (8 26 46 70 '168 200 400 SA LT 0 X I D AT i 0 N POT E N T I A k [ U (I PB I/' U ( I I 1 Pig, 17, Cracking behavior sf HasteE1~gr-N exposed 260 h at 900°C to MSBR fuel salt containing Cr3Te4 and Cr5Teg. Presently, the modified alloy composition shorn in Table 28 is fa- vored. Considerable progress had been made in establishing test methods for evaluating a rnaterialPs resistance to mbrittlment by teEPurfum. Modified Hastelloy-N containing from 1 to 2% rtiglbi~i~ was found to offer improved resistance to embrittlment by tellurium, beat the test conditions were not sufficiently long or diversified to show that the alloy totally resisted mbrittLment, h e irradiation experiment showed that the niobium-modified alloy offered adequate resistance to irradiation embrittlaent, but more detailed tests are needed. Several mall melts containing up to 4.4% niobium were found to fabricate and weld well, so products containllng 1 to 2% niobium likely can be produced with a minimum of scale-up difficulties. 3.4.1.3 Uncertainties Although no basic scale-up grobl@as are anticipated with the niobium- modified alloy, several large heats must be melted and processed into structural shapes to show that the all~y can be prod~eed eomer~ially~ A further need exists for longer exposure of tkfs alloy to irradiation
... w . . .y and to salt containing tellurium to show that it will resist embrittle- ment by these two processes aver long periods of time. Numerous mechan- ical property tests must be run needed for ASME Boiler and Pressure Vessel Code appr~val of the alloy and to establish adequate design methods. 3.4.2.1 hquiKementS the new alloy to develop the data 3.4.2 Moderator The graphite in a single-fluid molten-salt reactor serves no structural purpose other than to define the flow patterns of the salt and, sf course, to support its om weight. The requirements ~n the material are dictated nost strongly by nuclear considerations, that is, stability of the material against radiation-induced dist~rtion and nonpenetrability by the fuel-bearing molten salt. Practical limitationas of meeting these requirements impose conditions on the core design- specifically the neces- sity to l imit the cross-sectional area of the graphite prisns. quirements of purity and impermeability ts salt are easily met by several hfgh-quality fine-grained graphites, and the main problems arise from the requirement of stability against radiation-induced distortion. 3.4.2.2. Status sf development The re- The dimensional changes ~f graphite during irradiation have been studied for a number of years. The dimensional changes largely depend on the degree of crystalline isotropy, but the volume changes fall into a rathear consistent pattern. tion QCCUPS first during which the vslurae decreases, and a period of swell- ing then occurs in which the vo%me increases. concern only because of the dimensional changes that take place, and the second period is sf concern because of the dimensional change and the formation of cracks. The formation of cracks would eventually allow salt to penetrate the graphite. Data shown in Fig. 18 are for 7%5"C, and the damage rate increases with increasing temperature. Thus, the graphite section size should be kept small enough to prevent temperatures in the graphite frm greatly exceeding those in the salt. As shorn in Fig. 18, a period of densffica- The first period is of
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P iii CONTENTS ....................
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CONCEPTUAL DESIGN CHARACTERISTICS O
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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.
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!I \.... . , . ~ .... .. . . / I I
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... .. ...... . . . $i 13 Table 1.
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15 Initial scoping studies showed t
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.. . E 6> I S N 0.45 k- 0.50 B --.
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:.:..y ,. . . w, E9 The code calcul
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h 3. Additional 238Y is added as re
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...z,y .. . c .A, Table 9. Actinide
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';x.w' .... Relative power distribu
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........ . . . :..i 27 a Inner 2.54
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29 Table 16. Effect of neutron spec
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ob E 2 a 4 5 6 7 8 9 10 11 12 13 14
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.. . . . . . . . . . '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: ..... i.. ....., . .Yd 85 QRPIL-DWG
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
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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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.... ..
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156 77. He 6. MacPherson, Institute
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