JT-60SA reference design scenarios at high (#3) and low (#2) density have been analyzed with the help of the self-consistent COREDIV code. Simulations results for standard carbon wall and the full W have been compared in terms of the influence of impurities, both intrinsic (C, W) and seeded (N, Ar, Ne, Kr) on the radiation losses and plasma parameters. For the scenario #3 in carbon environment the regime of detachment on divertor plates can be achieved with N or Ne seeding, whereas for the low density and high power scenario (#2), the carbon and seeding impurity radiation does not e?ectively reduce power to the targets. In this case only increase of neither average density or edge density together with Kr seeding might help to develop conditions with strong radiation losses and semi-detached conditions in the divertor. The calculations show that in case of tungsten divertor the power load to the plate is mitigated by seeding and the central plasma dilution is smaller compared to the carbon divertor. For the high density case with neon seeding operation in full detachment mode is observed. Ar seems to be an optimal choice for the low density high power scenario #2, showing wide operating window, whereas Ne leads to high plasma dilution at high seeding levels albeit not achieving semi-detached conditions in the divertor.