Thermo-hydraulic analysis on in-bed calorimetry in a thin double-layered annulus metal hydride bed

Abstract Korea has been developing the metal hydride beds for the ITER storage and delivery system (SDS). There are two major concerns for the bed: one is the rapid delivery/recovery rate according to the tokamak plasma operation scenarios, and the other is the accurate measurement of tritium inventory using in-bed calorimetry within limited time. One of the bed concepts considering now consists of the thin and double layers of ZrCo which are confined by the cylinder-shaped SUS filter and the primary vessel wall. The primary vessel wall is wound by the heating coils, and has the helium channels for the in-bed calorimetry. In this study, the three-dimensional thermo-hydraulic analysis is performed for the bed to investigate the in-bed calorimetry performance. Based on the transient simulation results with an assumption of complete removal of the decay heat by He-loop, it is found that the bed under pre-cooling condition satisfies the accountancy of ±1 g-T accuracy in 24 h and ±3 g-T accuracy in 8 h.