Development of ZrCo beds for ITER tritium storage and delivery

Assuming a practical use in ITER facility, rapid recovery and supply of tritium to accommodate pulsed plasma operation cycle with minimal inventory was tested. For this purpose, tritium will be supplied from heated bed with vacuum pump while heat of reaction is supplied externally. For recovery, hydriding reaction occurs at elevated temperature spontaneously. Kinetic behavior of the bed at the temperature around 300 degree-C was studied, and practical operation was successfully demonstrated. Isotopic composition change due to the difference of equilibrium temperature was concerned in supplying mixture, but the effect was found to be negligible. For rapid accountancy, ITER requirement of accuracy (+/-1%) was demonstrated by 25 g tritium storage ZrCo bed with "In-bed" gas flowing calorimetry. It was revealed that the accuracy is affected by the surrounding temperature, that could readily be controlled for better measurement. Thus technology and experience on storage and transport of large amount of tritium, that are inevitable in fusion tritium facility such as ITER Tritium Plant have been established by Japanese research facility and industry.