Fast-Reactor Calculational Models

Three new models have been developed for fast-reactor physics calculations. These were obtained from the energy-dependent P₁ equations by a modal expansion of the neutron flux. For certain classes of problems, these models provide attractive alternatives and supplements to conventional multigroup finite-difference models, in that considerable reductions in complexity and computational effort are realized. Integral experimental data can be used directly in one of the models, and physical insight can be incorporated into all the models via the choice of expansion modes. Each of the models was applied to calculate the integral properties of fast-reactor critical assemblies.