Safety analysis for power-to-melt test

Morii, Tadashi*; not registered; not registered; Chitose, Keiko*

In the experimental fast reactor "JOYO", PNC (Power Reactor and Nuclear Fuel Development Corporation) schedules two new tests programs in near future in order to verify high-power and high-burnup capability of LMFBR fuel pins : PTM (Power-to-Melt) test and RTCB (Run, to-Cladding Breach) test. The following safety analysis necessary to get a license for the PTM test has been performed in this study. (1)Caluculate test conditions of fuel, cladding and coolant temperature and the cladding strain of test pins. (2)Confirm that the cladding of test pin has not been broken in touch with molten fuel which oozes from central melting zone of the pin and also that taking account of the axial movement of liquid fuel strain of the cladding caused by thermal expansion of solid fuel is about 0.6%, Which is less than 3% of the cladding breaking strain. (3)Calculate temperature increases due to a mistaken setting up of coolant flow of test assembly and fing the condition which satisfies representative safety criteria.