Effect of Moderation on Damage Flux in Fast Reactors

The effect of moderator incorporation in a fast reactor on the magnitude of the integrated neutron flux above 1 MeV (damage flux) is examined. Numerical results utilizing a diffusion-theory model are presented for fuel-moderator mixtures and thermionic converter-moderator mixtures. The effect on the damage flux of core power density reduction is shown to be far more significant than that of the removal properties of the moderator.