Abstract: The effects of nuclear heating on material in both fu el regions and nonfuel regions are analyzed with different enrichment of  235U in China advanced research reactor (CARR). The results show that the heating effect in fuel regions can be neglected. In nonfuel regions, the γ he ating which is the main contribution of nuclear heating is classified in differe nt original sorts and analyzed by both theoretical analysis and MCNP calculation s with the example of CARR cold neutron source moderator cell.