[2B01-05] Criticality Safety (Fuel Debris)

[2B04] Criticality safety analysis in fuel debris falling down simulation using MPS in real scale geometry

*Taro Fumimoto¹, Takeshi Muramoto¹, Jun Nishiyama¹, Toru Obara¹ (1. Tokyo Tech)

Keywords:Fukushima Daiichi Nuclear Power Station Accident, Criticality Safety, Fuel Debris, Moving Particle Simulation, Monte Carlo Simulation

If fuel debris fall into the water during the fuel debris recovery work at the Fukushima Daiichi Nuclear Power Station, it may lead to a criticality accident. The purpose of this study is to clarify the possibility of criticality analysis of fuel debris falling down in water in real scale geometry by MPS and neutron transport Monte Carlo calculation. The possibility was investigated to improve the calculation speed by changing the parameters. It was also investigated the possibility that simulation could be prevented by the limitation of memory size of the server. It was clarified that the simulation and the criticality calculation in real scale geometry are possible in acceptable calculation time.