ABSTRACT
The scattering reaction is also important for criticality considerations because of the effect it has on reducing the neutron energy of the scattered neutron. The most important effect comes from elastic scattering, the predominant form of scattering in the energy range of interest to reactor, criticality problems. Specialized deterministic computer codes solve these coupled linear algebra equations for the neutron flux in each phase cell, the desired flux integrals are approximated by summations over the appropriate cells to get the engineering parameters of interest in the analysis. Stochastic methods solve for the neutron flux by simulating particle transport rather than by numerically solving the Boltzmann transport equation. Once the analysis limits of the physical parameters have been determined, the final step involves determining, documenting the allowed process conditions and required controls. In the reaction rate point of view, the important physical parameters are the neutron cross sections, which give the probabilities of various reactions occurring when neutrons interact with nuclei.
