Long-Term Tritium Accountability Demonstration of ZrCo Storage Bed by “In-Bed” Gas Flowing Calorimetry

The accountancy of tritium stored in the Zirconium-Cobalt (ZrCo) bed with 25 g of tritium storage capacity has been investigated by “in-bed” gas flowing calorimetric method for a few years. This type of calorimetry uses the temperature raise of helium (He) gas circulated through a secondary coil line installed in the ZrCo tritide. Recently, the basic calorimetric characteristics was demonstrated well within 1 % accuracy of the ITER requirement using 22 g of tritium under actual storage system conditions, such as hydrogenation-dehydrogenation of tritium, long-term storage (³He accumulation inside of tritide vessel), and DT mixture storage. Based on the experimental data, a 100 g of tritium storage bed (ITER size) was designed and its calorimetric performance was discussed.