Tritium inventories and tritium safety design principles for the fuel cycle of ITER

Within the Tritium Plant of ITER a total inventory of about 2 to 3 kg will be necessary to operate the machine in the DT phase at a throughput of about 1 kg tritium per hour. During plasma operation, tritium will be distributed in the different subsystems of the fuel cycle. A tool for tritium inventory evaluation the dynamic model (TRIMO) of the tritium content in each sub-system of the Fuel Cycle of ITER was developed. The code reflects the design of each system; both the physical processes characteristics of each system and the associated control systems are modeled in TRIMO. The confinement of tritium within the respective systems of the Fuel Cycle is one of the most important safety objectives. The design of the deuterium/tritium fuel cycle of ITER includes a multiple barrier concept for the confinement of tritium and has two major features, namely a two (primary and secondary) barrier design and secondary containment atmosphere and gaseous waste treatment systems. Ultimately the building is equipped with a vent detritiation system and re-circulation type room atmosphere detritiation systems, required as an emergency tritium confinement barrier during possible accidental events. In order to assure a high integrity of the tritium bearing systems within the ITER Tritium Plant the design considers largely protection measures (mainly overpressure and overtemperature protection). (author)