Neutronics effects of homogeneous model on solid breeder blanket of CFETR

Abstract In the design of solid breeder blanket, normally the homogenous model is used for the neutronics analysis to assess the performance of blanket, but the adaptability of homogenous model is neglected. Referring to the design of CFETR (China Fusion Engineering Test Reactor) blanket, impact assessments of homogeneous model with different coolants, helium and water, are investigated with 3D high-fidelity neutronics models in this paper. The neutronics effects of the homogeneous structure and space self-shielding are analyzed separately. The results show that the homogeneous model has small impacts on the neutronics performance for helium cooled blanket concept and the TBR (tritium breeding ratio) is overestimated by ∼2.5% for water-cooled blanket concept; the space self-shielding effect caused by pebble beds has little influence on the neutronics calculation for helium-cooled concept, but ∼1.3% TBR overestimation for water-cooled concept. Finally, the results verify that the homogeneous model is rational for neutronic analyses with helium coolant. However, the high-fidelity model should be adopted in the neutronics transport calculation because the homogeneous model overestimates the neutronics performance for water-cooled blanket concept.