STUDY ON EUTECTIC MELTING BEHAVIOR OF CONTROL ROD MATERIALS IN CORE DISRUPTIVE ACCIDENTS OF SODIUM-COOLED FAST REACTOR: (2) EFFECT OF B4C ADDITION ON THERMOPHYSICAL PROPERTIES OF AUSTENITIC STAINLESS STEEL IN A SOLID STATE

摘要

In a core disruptive accident scenario, the boroncarbide (B_4C) of control-rod material is expected to reactwith stainless steel (SS) of the structural material. Theproduced eutectic material of stainless steel containingboron carbide (SS-B_4C) is assumed to relocate widely inthe core. To add a function to explain this liquefactionand relocation behavior to core disruptive accidentanalysis codes, a database of SS-B_4C thermophysicalproperties must be maintained. In this work, the densityand specific heat of austenite stainless steel (316L SS)containing 7mass%B_4C in the solid state are obtained andcompared with that of 316L SS containing 5mass% B_4Cand the value of 316L SS in the literature. It is found thatas the B_4C concentration in the austenitic stainless steelincreases, the density decreases while the specific heatincreases. By adding 7mass%-B_4C to 316L SS, the densitydecreases 7% at 293K. On the other hand, specific heatincreases 21% at 293K.