Appendix A2: 235 U-Fueled and Pb–Bi–Zoned ADS Core
265
Table A2.9 (continued)
Neutron decay constants α [s −1 ]
Target
BF 3 #1 in (10, U)
BF 3 #2 in (15, X)
Optical fiber
Case I-4
W
1052.0 ± 7.5
1033.3 ± 8.8
1204.5 ± 16.6
W–Be
1033.2 ± 3.1
1027.7 ± 3.5
1073.8 ± 4.1
Pb–Bi
1006.3 ± 5.6
1004.1 ± 6.1
1083.2 ± 5.3
Case I-5
W
1844.6 ± 21.3
1845.9 ± 17.7
1922.5 ± 33.3
W–Be
1770.5 ± 3.7
1697.0 ± 4.6
1909.1 ± 3.9
Pb–Bi
1785.2 ± 9.4
1742.1 ± 8.7
1895.5 ± 11.1
Table A2.10 Measured subcriticality [pcm] deduced by the extrapolated area ratio method (Ref.
[1])
Subcriticality ρ [pcm] (by Area ratio method)
Target
BF 3 #1 in (10, U)
BF 3 #2 in (15, X)
Optical fiber
Case I-1 (Reference: ρ exp = 1360 pcm by experiment)
W
1132 ± 17
1393 ± 20
1888 ± 27
W–Be
1145 ± 18
1458 ± 21
1473 ± 21
Pb–Bi
1166 ± 18
1387 ± 20
1390 ± 20
Case I-2 (Reference: ρ exp = 2165 pcm by experiment)
W
1877 ± 27
2363 ± 35
3002 ± 44
W–Be
1879 ± 28
2463 ± 36
2229 ± 33
Pb–Bi
1926 ± 29
2356 ± 35
2252 ± 33
Case I-3 (Reference: ρ exp = 2900 pcm by experiment)
W
2398 ± 35
3156 ± 46
3822 ± 58
W–Be
2502 ± 39
3405 ± 51
2939 ± 45
Pb–Bi
2624 ± 39
3238 ± 48
2977 ± 45
Case I-4 (Reference: ρ MCNPX = 2773 pcm by MCNP)
W
2682 ± 39
3291 ± 48
3672 ± 55
W–Be
2688 ± 41
3483 ± 52
2910 ± 43
Pb–Bi
2738 ± 41
3302 ± 49
2922 ± 44
Case I-5 (Reference: ρ MCNPX = 4902 pcm by MCNP)
W
4944 ± 78
6386 ± 101
6228 ± 99
W–Be
5004 ± 83
7050 ± 114
4929 ± 77
Pb–Bi
4903 ± 77
6356 ± 92
4912 ± 74
(β eff = 807 pcm; = 3.050E-05 s by MCNP6.1 with JENDL-4.0)