ITER fuelling, pumping, wall conditioning systems and fuel dynamics analysis

In this paper, the status of the ITER fuelling, pumping and wall conditioning systems design and the results of fuel dynamics analysis will be presented. The fuelling system consists of both gas and pellet injection. The max. DT gas fuelling rate is 500 Pa m3 s−1 during a plasma density rise and 200 Pa m3 s−1 during steady state DT burn. The maximum pellet fuelling rate is 100 Pa m3 s−1 (DT) and 50 Pa m3 s−1 (T2) during DT burn. The primary pumping system comprises two major subsystems: the high vacuum pumping system and the torus roughing system. The former consists of 16 batch regenerating cryopumps located inside the divertor ports with 12 in operation and four in regeneration mode. The net pumping speed of 12 pumps is ∼200 m3 s−1. The latter consists of two sets of mechanical pumps, each containing an inlet Roots blower backed by two Roots blower/mechanical piston pumps. For wall conditioning, baking and glow discharge cleaning for zero-magnetic field, and electron cyclotron resonance discharge cleaning for high-magnetic field are being examined. Development of a fuel dynamics simulation code including the complete fuel cycle (fuelling, vacuum pumping and tritium plant systems) is in progress for an optimisation of the fuel cycle.