Thermal response of the multiplier of an accelerator driven system to beam interruptions.

Thermal response of the multiplier of an accelerator driven system to beam trips has been calculated for sodium cooled and lead-bismuth cooled multipliers. The temperature transients caused by a beam trip lead to thermal fatigue in structural components, and restoring the beam causes an additional temperature transient that adds to thermal fatigue. Design lifetimes for various multiplier components are calculated, based on the frequency of beam interruptions and on the thermal fatigue per interruption. Mitigation strategies to increase design lifetimes are discussed.