427. 鉄に感度を有する高速炉炉心の臨界性解析

抄録

Recently, it has been reported that the conventional calculation method for fast neutron systems loses its validity when it is applied to fast systems that are significantly sensitive to iron cross section. In the present paper, a newly developed cell calculation code, SLAROM-UF, has been applied to calculations for such systems. SLAROM-UF utilizes the ultra-fine energy group library below 50keV and the 900-group library to estimate the self-shielding effect caused by resonances of heavy nuclides and wide resonances of structural materials, respectively.
When SLAROM-UF with 900-group library was applied to cell calculation and core calculation was performed in a properly adopted 220-group structure, discrepancy of multiplication factor from the continuous energy Monte-Carlo calculation was reduced from 2.0 to 0.4%Δk.
Large dependency on energy group used for core calculation is observed in JOYO MK-III, It is caused by "the fuelreflector interface effect" which is recently discussed as a problem for calculation of fast neutron systems.