JAEA-Conf 2011-002 - 日本原子力研究開発機構
JAEA-Conf 2011-002 - 日本原子力研究開発機構
JAEA-Conf 2011-002 - 日本原子力研究開発機構
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ENDF. Thus this cross section stored in ENDF has not been revised more than 36 years at least.<br />
The cross section of JEFF-3.1 was taken from ENDF/B-VI.8[7], and it evaluated based on as old<br />
measurement data as ENDF.<br />
Table 1 Neutron capture cross section of carbon at 0.0253eV<br />
JENDL-4.0 JENDL-3.3 ENDF/B-VII.0 JEFF-3.1<br />
3.85mb 3.53mb 3.36mb 3.36mb<br />
2.4 Calculation conditions and method<br />
The criticality calculations for the 12-30 fuel columns loaded core with all control rods<br />
withdrawn at room temperature were performed with the continuous energy Monte Carlo code<br />
MVP[8] to obtain the keff value for each core state. The core geometry was treated as much<br />
detail as possible, and a heterogeneous effect caused by a coated fuel particle was taken into<br />
account by using a Statistical Geometry (STG) model[9]. The history number was defined<br />
8,000,000 for each calculation to reduce the standard deviation (1) to about 0.03%.<br />
3. Results and discussion<br />
Figure 3 shows calculated keff<br />
curves for the several HTTR core 1.15<br />
states, which were configured in<br />
JENDL-4.0<br />
JENDL-3.3<br />
the critical approach. JENDL-4.0<br />
yields the keff values which are<br />
1.10<br />
ENDF/B-VII.0<br />
JEFF-3.1<br />
smaller than the other libraries for<br />
Excess reactivity<br />
the all core states. Specifically, the<br />
1.05<br />
for fully loaded core<br />
keff values<br />
JENDL-4.0<br />
calculated with<br />
are 0.5-0.9%k 1.00<br />
k = 1 eff<br />
smaller than JENDL-3.3, and are<br />
First criticality<br />
1.0-1.5%k smaller than<br />
ENDFL/B-VII.0 or JEFF-3.1. The<br />
keff values calculated with<br />
0.95<br />
12 14 16 18 20 22 24<br />
Number of loaded fuel column<br />
26 28 30<br />
ENDF/B-VII.0 and JEFF-3.1 are<br />
the same within 2 for the each core states.<br />
Fig. 3 keff curves for each core states<br />
k eff<br />
<strong>JAEA</strong>-<strong>Conf</strong> <strong>2011</strong>-<strong>002</strong><br />
3.1 Loaded number of fuel columns achieving first criticality<br />
The loaded number of the fuel columns at the first criticality is determined by<br />
identifying the first column with which the keff value is more than 1.0. Thus, the keff curve with<br />
JENDL-4.0 indicates that the first criticality is achieved by loading 19 fuel columns, which<br />
agrees with the experimental result. Meanwhile, the keff curves with JENDL-3.3,<br />
ENDF/B-VII.0 and JEFF-3.1 indicate the first criticality is achieved by loading 18, 17, and 17