Reaction Rate Calculation in Fast Reactor Blanket Using Multiband S_nTheory

Abstract

A new method was applied to calculation of reaction rates in blanket of LMFBR using the multiband Sn theory. This procedure leads to the use of direction dependent total micro cross sections, which advances the penetration of neutrons into the blanket.Test calculation with RZ model of a prototype fast reactor shows that reaction rates tend to rise with the penetration into blanket compared to the conventional multigroup calculation: the maximum difference was about 3% for 238 U capture, 4% for 235 U fission, 4% for 239 Pu fission, and less than 1% for 238 U fission. This tendency shows the same direction as the difference observed between the continuous energy Monte Carlo method and the conventional method.