ナトリウム冷却高速炉の炉心崩壊事故における制御材と溶融ステンレス鋼の反応挙動に関する実験的研究

抄録

In the core disruptive accidents (CDAs) of sodium-cooled fast reactors (SFRs), the eutectic reaction between boron carbide (B₄C) as a control rod material and stainless steel (SS) as a structural material could occur below the melting points of both B₄C and SS. Therefore, the loss of control rod materials and the movement of these reaction products toward inside or outside of the original core region could affect the core reactivity in CDAs of SFRs. In this study, the immersion tests using the B₄C pellets with the molten SS were conducted to evaluate the CDA consequences in SFRs such as the contact event of solid B₄C with molten core materials including SS under the condition of anticipated transient without scram (ATWS). Based on the reduction thicknesses of B₄C pellets after the tests, the reaction rates were discussed.