Transient behavior of silicide fuel-reactivity insertion by cold coolant induction

Yanagisawa, Kazuaki

By using a mini-plate fuel (density 4.8g/cc) fabricated as a simulation of JMTR silicide fuel plate, an in-core irradiation test postulating a reactivity insertion by cold coolant induction was performed. The test is known as an abnormal transient phenomenon to be caused during JMTR operation. Taking into account that the peak cladding surface temperature predicted by EURECA computer code for JMTR safety evaluation is 53 C in maximum, more severe condition is imposed on in-core tested mini-plate fuel, where a peak cladding surface temperature is as high as 111 C. It is revealed from post-irradiation examination that the tested mini-plate fuel was intact. From this experimental fact, it is found that JMTR silicide fuel plate has a safety margin against a reactivity insertion by cold coolant induction.