Criticality safety research for safe and efficient handling of nuclear material / acquisition of critical mass data, validation of analysis method, and framework to prove the safety

Tonoike, Kotaro 

Criticality safety is important for fuel cycle facilities (FCFs) where nuclear materials of various kinds and a large quantity are being handled; therefore researches are conducted for prevention of anomaly, prevention of escalation, and mitigation of influence. Efforts have been focused, especially, on the prevention of anomaly due to difficulty of handling criticality accidents. Today, criticality safety design and evaluation of FCFs depends on computation using analysis codes and nuclear data, for which it is essential to validate that the computation is correct. Thus, JAEA has consistently performed acquisition of critical mass data by critical experiments, building models for validation, validation of analysis codes and nuclear data, and computation of basic criticality data. It is expected that new fuel design with higher fissile contents is going to be employed for more advanced utilization of light water reactors. JAEA will be engaged in researches on new criticality safety control methods such as the burn-up credit and/or the poison credit.