The final design review of the gas distribution manifold system, part of ITER's
gas injection system, was held from 8 to 10 December 2015 in Chengdu, China. More than 40 participants attended the review either on-site or remotely, including 13 panel members and participants from the ITER Organization, the Chinese Domestic Agency, and the contracting institute Southwestern Institute of Physics.
The gas injection system in ITER is responsible for the "initial fill" of the vacuum chamber prior to plasma initiation; for puffing gas into the chamber during the ramp-up phase; for controlling plasma density during the flattop of plasma burn; and for protecting the divertor targets from discharges by injecting impurity gases.
In order to service the pellet injection, gas fuelling, neutral beam and disruption mitigation systems, different gas species from the Tritium Plant (hydrogenic species, helium, and the impurity gases argon, neon and nitrogen) will be delivered via a gas distribution manifold to gas valve boxes located in the vacuum vessels ports. According to the ITER machine assembly schedule, this gas distribution manifold system is expected on site before the rest of the gas injection system; for this reason, a separate design review was organized.