Analysis of nuclear response in CFETR toroidal field coils with density reduction VR technique

摘要

The China Fusion Engineering Test Reactor (CFETR) has been designed as steady-state operated tokamak device. The CFETR new engineering design has been initialized corresponding to the latest core parameters (major/minor radius is R = 7.2 m/a = 2.2 m). The nuclear analysis of CFETR was carried out to evaluate the neutron shielding capabilities and nuclear responses to toroidal field coils (TFC). The 3D neutronics model of CFETR was built with the support of McCad tool to convert the CAD model automatically. An extended variance reduction (VR) technique of combined MAGIC GVR with density reduction method has been involved to generate suitable weight windows to enhance the efficiency of particle transport. Highly detailed neutron and photon map has been obtained which meet the requirements for Monte Carlo nuclear analyses. The global neutron flux distribution of 3D CFETR with P-f = 200 MW to 1.5 GW was obtained to evaluate its shielding performance. The nuclear responses to TFC such as the nuclear heating and fast neutron fluence have been evaluated. Initial results show the shielding of current divertor design is not sufficient and the optimizing work has been done. The final results satisfy the referred ITER design limit and it can provide the support for the future more detailed design of divertor and other shielding systems.