Response of ITER to loss of vacuum accidents

Air leakage into the ITER vacuum vessel initially under vacuum during plasma burning or maintenance operations may lead to chemical reactions and to its pressurisation. Production of energy, generation of large amounts of reaction products and radioactivity mobilisation may be induced. In the frame of the Non-Site Specific Safety Report (NSSR-1), this paper analyses and provides pressure transients inside the vessel, resulting in inlet or outlet gas flows and amounts of activated materials released to the connected room and finally to the environment. It is shown that even during plasma burning phases, the amount of reaction products remains limited or negligible. Moreover, the final releases to the environment are well below the corresponding release limits.