[1M08-13] Criticality Safety 1

[1M10] Criticality control technique development for Fukushima Daiichi fuel debris

(41) Statistical evaluation of criticality - The criticality evaluation of 1F-2/1F-3 RPV lower part debris with considering non-uniform positioning of UO2+Gd2O3

*Takuya UMANO^1,2, Mitsuaki YAMAOKA^1,2, Rei KIMURA^1,2, Yamato HAYASHI^1,2 (1. International Research Institute for Nuclear Decommissioning, 2. Toshiba Energy Systems & Solutions Corporation)

Keywords:Fukushima Dai-ichi Nuclear Power Plant, Fuel debris, Criticalty Safety, UO2+Gd2O3, MVP, STGM(Statistical Geometry Model)

This is one of the nine series presentation contents for the results in the fiscal year 2017 as for the national project named “Criticality control technique development for Fukushima Daiichi fuel debris.” The possibilities of re-criticality were calculated with the MVP code and JENDL-4.0 for 1F-2 and 1F-3 RPV lower part of fuel debris after filling water. The Statistical Geometry Model (STGM) usable in the MVP code was adopted. Moreover, based on the detail atomic number densities calculated with the Fukushima Daiichi core management code CASMO, a preliminary evaluation of criticality was carried out with considering non-uniform positioning of UO2+Gd2O3.