Nuclear Response Analysis of TFC for CFETR-I Using an Optimized GVR Approach

The nuclear analysis of the toroidal field coil (TFC) has been performed using China Fusion Engineering Test Reactor (CFETR)-I model of 33.75-degree torus sector with a pitched Neutral Beam Interface port. A novel optimized global variance reduction (GVR) approach has been applied to Monte Carlo N-Particle Transport Code (MCNP) simulation process to improve parallel computing efficiency. The nuclear response in TFC includes the nuclear heat density, the integral nuclear heat, the absorbed dose, the fast neutron fluence and the total neutron fluence. Those data were calculated and compared with the International Thermonuclear Experimental Reactor (ITER) design limits. The results show that the fast neutron fluence, total neutron fluence and absorbed dose in some parts of inboard insulator exceed the ITER design limits, which means that more advanced shield materials should be used in radiation shielding design.