Numerical analyses for initial-designed CFETR baseline scenario with the integrated COREDIV code

The self-consistent core-edge integrated COREDIV code has been used to simulate the baseline scenario of the China Fusion Engineering Test Reactor (CFETR) with full tungsten (W) divertor. The influence of both intrinsic (W) and extrinsic seeded (Ne, Ar, Kr) impurities on the radiation losses and plasma parameters has been analyzed. It is found that when the W concentration in the core plasma region is higher than 5 × 10⁻⁵, H mode cannot be sustained due to the large core radiation losses. Kr seeding seems to be infeasible because of high contribution to the core radiation and high W sputtering yield. Better plasma performance can be obtained with higher electron density at the separatrix because of lower W penetration in the core due to increased screening efficiency in the scrape-off layer (SOL). According to the COREDIV model, W prompt re-deposition has almost no influence on the W source, because high prompt re-deposition fractions occur at the divertor region with low sputtered W flux. In the case of Ne or Ar seeding, under the condition of both higher n_{e_sep} and W re-deposition fraction (>90%), the scenario can be operated in H mode with sustainable conditions in the divertor region.