JAERI 1287 JNDC Nuclear Data Library of Fission Products Fir

16 JNDC Nuclear Data Library of Fission Products JAERI 1287
as follows:
Zp(A) = Zp(A, Standard) + AZp(Ternary)+dZp(A). (2.4.4)
The first term in the right hand side is the standard value for thermal-neutron fission of 23S U
and it is tabulated in Table A-11 of Ref. 48. The second term is the correction term for ternary
fission, and the third term is further decomposed into the following three terms.
4Zp(A)=a(Zc-92)+b(Ac~-236)+c(E*-6.52), (2.4.5)
where Zc and Ac are the charge and mass number of the compound nucleus, respectively,
and E* is the excitation energy in MeV. The values of the coefficients a, b and c were determined
by a least-squares treatment of the available fractional chain yield data for spontaneous
and neutron induced fissions 48 ^. Nethaway derived the values,
a = 0.414 ± 0.016 and b = -0.143 ± 0.007 for light fragment products;
a = 0.547 ± 0.010 and b = —0.183 ± 0.004 for heavy fragment products;
a = 0.50 ± 0.03 and b = —0.165 ± 0.02 for valley products.
Mass No.
66- 74
76
78
80
82
84
86
88
90
92
94
96
98
100
102
Table 2.4.3 Values of the parameter c for the evaluation of the most probable charge
c
0.0200 ±0.0030
0.0200 + 0.0025
0.0200 ±0.0025
0.0200 ±0.0020
0.0200 + 0.0016
0.0200 + 0.0016
0.0200 ±0.0016
0.0196 ±0.0012
0.0189 ±0.0011
0.0181 ±0.0011
0.0171 +0.0010
0.0160 ±0.0010
0.0157 ±0.0009
0.0159 ±0.0013
0.0173 ±0.0017
Mass No.
104
106
108
110
112
114
116
118
120
122
124
126
128
130
132
c
0.0190 ±0.0023
0.0211 ±0.0030
0.0233 ±0.0037
0.0257 ± 0.0046
0.0283 ±0.0057
0.0311 ±0.0062
0.0341 +0.0068
0.0371 +0.0067
0.0402 ± 0.0064
0.0433 ±0.0061
0.0464 ±0.0056
0.0495 ±0.0050
0.0505 ±0.0041
0.0509 ±0.0031
0.0500 + 0.0025
Mass No.
134
136
138
140
142
144
146
148
150
152
154
156
158-172
Table 2.4.4 Correction factor Azp {Ternary) due to ternary
fission 41 ), mass number Ac, and excitation
energy £* (MeV) of compound nucleus 48 )
Fissile
235 U(T)
235 U(F)
23S U(H)
238 U (F)
238 U (H)
239 Pu (T)
239 Pu (F)
241 Pu (T)
233 U (T)
232 Th (F)
AZP {Ternary)
0.05062
-0.10021
-0.06241
-0.00860
-0.10089
0.01846
-0.06287
-0.08924
0.03989
0.01299
Zc
92
92
92
92
92
94
94
94
92
90
Ac
236
236
236
239
239
240
240
242
234
233
£*(MeV)
6.52
8.31
21.26
6.57
19.52
6.50
8.30
6.27
6.81
6.56
c
0.0472 ± 0.0024
0.0416 ±0.0021
0.0329 ±0.0016
0.0276 ±0.0014
0.0241 +0.0012
0.0217 ±0.0013
0.0203 +0.0016
0.0195 +0.0019
0.0195 ±0.0023
0.0195 + 0.0027
0.0195 ±0.0031
0.0195 ±0.0035
0.0195 ±0.0039