Modeling and analysis of tritium transport for updated WCCB blanket of CFETR

Radioactivity source item assessment has become an essential part of safety evaluations for the China Fusion Engineering Test Reactor. Thus, numerical simulations of tritium transport in a water-cooled ceramic breeder blanket are performed in this study. 2D and 3D multi-physics convection-diffusion models that couple velocity and temperature fields are built to estimate tritium permeation and other tritium-related quantities. The 2D tritium transport model is used to evaluate tritium permeation under various helium purge gas velocity conditions in the breeder zone. The quantity of tritium permeation, tritium inventory, and amount of tritium transported by the purge gas are determined. In addition, a 3D model is used to determine tritium-related quantities with better accuracy. The 2D and 3D models are compared using a fixed purge gas condition.