Assessment of Tritium Release Through Permeation and Natural Leakage in ITER CN HCCB TBS Under Normal Operations

The Chinese (CN) Helium Cooled Ceramic Breeding (HCCB) Test Blanket Module (TBM) (CN HCCB TBM) set with its ancillary systems will demonstrate the feasibility of in-pile tritium production/breeding in ITER for fuel self-sufficiency and high-grade fusion energy conversion to heat and extraction for a future magnetic confined fusion reactor. Tritium release in some major components of the recently designed TBM systems through permeation and natural leakage was estimated with simple diffusion/permeation and leak rate calculation models. Results showed that because of the tritium permeation barrier coating for tritium confinement in some tritium containments, total tritium release to the environment by permeation in the CN HCCB TBM and ancillary systems will be kept well below 2 Ci/full-power day. However, tritium release through natural leakage from components can be neglected compared with permeation. Equipped with ITER tritium safety guarantee facilities like the tritium monitoring and detritiation systems, tritium release from CN TBM system–caused radiological safety issues will be well controlled.