[1E07-11] Severe Accident1

[1E08] Development of Passive Debris Cooling System Phase II

(4)Optimization of Refractory Material Laying Structure

*Tomonori Kimura¹, Masafumi Nojima¹, Tadashi Fujii¹, Yoichi Onitsuka², Takumi Yoshikawa³ (1. HGNE, 2. TOSHIBA ESS, 3. JAPC)

Keywords:severe accident, MCCI (Moten Core Concrete Interaction), passive debris cooling system

For improving safety at the severe accident of existing BWRs, it is necessary to suppress the MCCI (Moten Core Concrete Interaction). One of the countermeasures for MCCI is to install an equipment consisting refractory material with high melting point at the side and bottom of the primary containment vessel (PCV). In this study, chemical reactivity at around eutectic temperature of the passive debris cooling system consisting of multi-layering of ZrO2 refractory material and Al2O3 refractory material was evaluated to clarify design requirements. In addition, from thermal conductivity evaluation after molten core fell into PCV in representative plant, the system specification to suppress the chemical reaction at eutectic temperature between ZrO2 refractory material and Al2O3 refractory material and prevent MCCI were found out.