Reaction Rate Calculation in Fast Reactor Blanket Using Multiband Sn Theory

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 238U capture, 4% for 235U fission, 4% for 239Pu fission, and less than 1% for 238U fission. This tendency shows the same direction as the difference observed between the continuous energy Monte Carlo method and the conventional method.