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Description
Tungsten and RAFM steel are respectively used as armor material of first wall (FW) and structure material. The Li2TiO3/Be12Ti mixed pebble bed is selected to fulfill tritium breeding for water-cooled ceramic blanket (WCCB) in China Fusion Engineering Test Reactor (CFETR). Tritium would be existed in all materials of the blanket because of its diffusivity and permeability. Thus, it is crucial to study the tritium retention and permeation in the main domains for the safe operation of blanket, especially considering the radioactivity of tritium. Based on the Finite Element Method (FEM), a two-dimensional tritium transport model is set up using COMSOL Multiphysics. The temperature field is constructed to display the temperature distribution within the model, considering the nuclear heat generated and the cooling of the coolant. The velocity field of He purge gas is simulated to analyze the ability of the helium purge gas making tritium entering into Tritium Extraction System (TES). Meanwhile, the processes of tritium diffused through the interface of different materials, permeated into the coolant and taken by purge gas are considered to calculate the tritium retention and permeation coupling with the temperature and velocity fields. The calculation results indicate that the permeation amount into the coolant of FW is 2.18×10-6mg/s, while that of four cooling plates is 2.70×10-6mg/s. In the purge gas, the tritium would be carried out at the speed of 1.27×10-3mg/s, assuming the existing HTO totally entering into TES. The retention in the inner pebbles is 0.03g. The accuracy of the result is also discussed in this paper.
| Eligible for student paper award? | Yes |
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