Assessment of T inventory in ITER WCLL TBM with TESSIM-X

The ITER Test Blanket Module (TBM) is tasked with demonstrating efficient breeding and extraction of tritium inside the environment of a nuclear fusion reactor. In order to meet the strict requirements for tritium self-sufficiency necessary for future fusion power plants, and to address safety concerns and minimize radioactive waste, retained T inventory in and T losses out of the TBM must be accurately assessed. In this work, at the request of F4E, T losses due to retention and permeation in the ITER Water-Cooled Lithium Lead (WCLL) TMB are studied with the aid of the TESSIM-X diffusion-trapping code. Due to the presence of neutron-induced traps in the structural materials, T losses in the TBM are now expected to be a factor of 5 - 10 times larger than what was previously thought.