Albedo calculations for candidate fusion reactor materials used in the inboard side of a compact tokamak reactor and the effects of using such materials on the tritium breeding

In this paper the total neutron albedo and associated energy distributions for 10 candidate fusion reactor materials have been calculated. The angular distributions of reflected neutrons for monodirectional 14.1 MeV neutrons incident on slabs of Pb, Be, and W are presented and the dependence of albedo on neutron energy and incident angle has been investigated. Finally, the impact on the tritium breeding of the outboard blanket of the choice of material used in the inboard side of the reactor has been assessed. It has been found that the largest total neutron albedos are those of neutron multiplying materials, whilst among non-multiplying materials tungsten yields the largest albedo and B₁₀H₁₄ yields the lowest. Tritium breeding ratio (TBR) calculations have shown the inadequacy of the neutron albedo concept in predicting the impact of inboard materials on the TBR of the reactor.