Tritium inventory measurements by ''in-bed'' gas flowing calorimetry

In order to establish the ''in-bed'' tritium accounting technology for the ITER scale tritium storage system, a gas flowing calorimetry has been studied using a scaled ZrCo bed (25 g tritium capacity). The basic calorimetric characteristics, steady state temperature raise of He gas stream flowing through a secondary coil line fixed in the ZrCo tritide, was measured and correlated with the stored tritium inventory. The results shows that about 4 degrees raise of He stream temperature call be detected for each gram of tritium storage: The sensitivity of this calorimetry is about 0.05 g of tritium. calculated by 0.2 degrees of temperature sensor error. The accuracy is better than 0.25 g of tritium on 25 g storage, evaluated by 2 times of standard deviation from the repeat measurements. This accuracy of < 1 % on full storage capacity is satisfied the target accountability to measure +- 1 gram of tritium on 100 g storage for ITER.