[2E01-04] Next Generation Reactor Safety 1

[2E03] Development of a passive safety shutdown device to prevent core damage accidents in fast reactors

(5)The device structure concept and Basic evaluations of fuel migration behavior in the device by visualization experiments

*Yoshihiro Sekio¹, Isamu Sato², Masatoshi Kawashima³, Koji Morita⁴ (1. JAEA, 2. TCU, 3. Tokyo Tech, 4. Kyushu Univ.)

Keywords:fast reactor, core damage accident, passive safety, prevention of severe accidents

A proposed passive reactor shutdown device contains pins with fuels that are kept in the solid state during normal operation but melt into the liquid when its temperature exceeds a prescribed value under severe accidents. The device leads reactor to subcritical state by liquid fuel migration to low positions in the pins. In this study, the device structure for fast reactor core was proposed based on safety evaluation results. The liquid fuel is needed to migrate before the accident occurs, and the migration time would depend on the fuel viscosity. To obtain basic acknowledge for determination of fuel chemical components, the effect of material viscosities on fuel migration time was evaluated through visualization experiments using liquid samples with different viscosities.