92
M. Yamanaka
Table 4.6 Results of subcriticality on the basis of effective delayed neutron fractions estimated by
MCNP6.1, β RR
eigen , and β RR
source (Ref. [2])
Case Reference Subcriticality [pcm] Measured subcriticality [pcm]
β eff (MCNP6.1) β RR
eigen
(MCNPX-2.5.0)
β RR
source
(MCNPX-2.5.0)
I-1
1200 ± 36
1147 ± 17
(1.05 ± 0.02)
1111 ± 20
(1.08 ± 0.02)
1136 ± 61
(1.06 ± 0.06)
I-2
2012 ± 60
1847 ± 27
(1.09 ± 0.02)
1850 ± 30
(1.09 ± 0.02)
2032 ± 105
(0.99 ± 0.05)
I-3
2657 ± 80
2419 ± 35
(1.09 ± 0.02)
2400 ± 40
(1.11 ± 0.02)
2615 ± 136
(1.02 ± 0.05)
I-4
2722 ± 32
2679 ± 39
(1.02 ± 0.02)
2688 ± 44
(1.02 ± 0.02)
2745 ± 183
(1.00 ± 0.07)
I-5
4891 ± 50
5036 ± 84
(0.96 ± 0.02)
5134 ± 88
(0.95 ± 0.02)
5015 ± 354
(0.97 ± 0.07)
I-6
5291 ± 54
5489 ± 85
(0.97 ± 0.02)
5475 ± 95
(0.97 ± 0.02)
5877 ± 554
(0.90 ± 0.09)
I-7
7474 ± 75
8421 ± 144
(0.89 ± 0.02)
7952 ± 149
(0.94 ± 0.02)
8050 ± 874
(0.93 ± 0.10)
(): Calculation/experiment
the fission multiplication. And, in the case of different external neutron sources for
the deep subcritical core, as shown in Table 4.7, subcriticalities were compared in
terms of the k eff . The difference of the reference k eff between spallation and 14 MeV
neutrons is considered to be caused by the slight difference in the core configuration of the air gap shown in Figs A5.3 and A5.4. Here, the subcriticality with
β
RR
source was observed to reveal a comparative tendency through the comparison of the
subcriticality with β eff within the C/E value of 2%. The applicability of the proposed
methodology was also confirmed with the variation of the external neutron sources.
Table 4.7 Comparison of k eff and their C/E values estimated by MCNP6.1, β RR
eigen , and β RR
source in
different external neutron sources (Ref. [2])
Case Reference k eff
Measured k eff
β eff (MCNP6.1)
β RR
eigen
(MCNPX-2.5.0)
β RR
source
(MCNPX-2.5.0)
II-1
0.86397 ± 0.00008 0.89707 ± 0.00387
(0.96 ± 0.01)
0.89945 ± 0.00392
(0.96 ± 0.01)
0.88559 ± 0.00418
(0.98 ± 0.01)
II-2
0.84924 ± 0.00008 0.84775 ± 0.02543
(1.00 ± 0.03)
0.84516 ± 0.02581
(1.00 ± 0.03)
0.83243 ± 0.02743
(1.02 ± 0.03)
(): Calculation/experiment
M. Yamanaka
Table 4.6 Results of subcriticality on the basis of effective delayed neutron fractions estimated by
MCNP6.1, β RR
eigen , and β RR
source (Ref. [2])
Case Reference Subcriticality [pcm] Measured subcriticality [pcm]
β eff (MCNP6.1) β RR
eigen
(MCNPX-2.5.0)
β RR
source
(MCNPX-2.5.0)
I-1
1200 ± 36
1147 ± 17
(1.05 ± 0.02)
1111 ± 20
(1.08 ± 0.02)
1136 ± 61
(1.06 ± 0.06)
I-2
2012 ± 60
1847 ± 27
(1.09 ± 0.02)
1850 ± 30
(1.09 ± 0.02)
2032 ± 105
(0.99 ± 0.05)
I-3
2657 ± 80
2419 ± 35
(1.09 ± 0.02)
2400 ± 40
(1.11 ± 0.02)
2615 ± 136
(1.02 ± 0.05)
I-4
2722 ± 32
2679 ± 39
(1.02 ± 0.02)
2688 ± 44
(1.02 ± 0.02)
2745 ± 183
(1.00 ± 0.07)
I-5
4891 ± 50
5036 ± 84
(0.96 ± 0.02)
5134 ± 88
(0.95 ± 0.02)
5015 ± 354
(0.97 ± 0.07)
I-6
5291 ± 54
5489 ± 85
(0.97 ± 0.02)
5475 ± 95
(0.97 ± 0.02)
5877 ± 554
(0.90 ± 0.09)
I-7
7474 ± 75
8421 ± 144
(0.89 ± 0.02)
7952 ± 149
(0.94 ± 0.02)
8050 ± 874
(0.93 ± 0.10)
(): Calculation/experiment
the fission multiplication. And, in the case of different external neutron sources for
the deep subcritical core, as shown in Table 4.7, subcriticalities were compared in
terms of the k eff . The difference of the reference k eff between spallation and 14 MeV
neutrons is considered to be caused by the slight difference in the core configuration of the air gap shown in Figs A5.3 and A5.4. Here, the subcriticality with
β
RR
source was observed to reveal a comparative tendency through the comparison of the
subcriticality with β eff within the C/E value of 2%. The applicability of the proposed
methodology was also confirmed with the variation of the external neutron sources.
Table 4.7 Comparison of k eff and their C/E values estimated by MCNP6.1, β RR
eigen , and β RR
source in
different external neutron sources (Ref. [2])
Case Reference k eff
Measured k eff
β eff (MCNP6.1)
β RR
eigen
(MCNPX-2.5.0)
β RR
source
(MCNPX-2.5.0)
II-1
0.86397 ± 0.00008 0.89707 ± 0.00387
(0.96 ± 0.01)
0.89945 ± 0.00392
(0.96 ± 0.01)
0.88559 ± 0.00418
(0.98 ± 0.01)
II-2
0.84924 ± 0.00008 0.84775 ± 0.02543
(1.00 ± 0.03)
0.84516 ± 0.02581
(1.00 ± 0.03)
0.83243 ± 0.02743
(1.02 ± 0.03)
(): Calculation/experiment