EXPERIMENTS ON THE BEHAVIOR OF A HOT-MELT INJECTED INTO SODIUM

Molten fuel/coolant interaction has been recognized as a key issue in the event of a reactor core disruptive accident. To support the theore tical work in this field, a series of simulation experiments was carri ed out. 5 kg of thermite melt at 3270 K were injected from below into a sodium pool at 770 K. The melt consisted of either mainly alumina or mainly iron. The spatial development of the interaction region into t he sodium could well be understood by the instrumentation and X-ray ci nematography diagnostics. The thermal interactions were observed to oc cur as a sequence of small local pressure events, mainly during the in jection period. A large-scale vapour explosion was not observed. The c onversion ratios of thermal to mechanical energy were generally low ( less than or equal to 0.3%). Application of the AFDM code has helped t o understand better the physical phenomena, like the melt jet break-up , that govern the thermal interaction process. (C) 1998 Elsevier Scien ce Inc. All rights reserved.