Methods for Calculating Neutron Transfer Probabilities Between Assemblies

Abstract

We explore two methods for determining the probability that a neutron, upon leaking, will transfer from one spherical assembly to another, namely, the view factor method (VFM) and the sphere point picking method (SPPM). The VFM is an approximate analytical method that assumes the neutron is leaking from a point source, and therefore, has applicability limitations. The SPPM is a purely Monte Carlo method that samples a location on the surface of a sphere as well as a trajectory leading away from said system to then determine if the neutron streams into another assembly. Numerical results from the two methods are contrasted, and the relative merits of each method discussed.

Keywords:

• View factor method
• sphere point picking method
• Monte Carlo

Acknowledgments

This work was supported by the U.S. Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy (contract no. 89233218CNA000001). The authors gratefully acknowledge helpful discussions with Joseph Schmidt, Scott Ramsey, and Daniel Garcia of LANL.

Disclosure Statement

No potential conflict of interest was reported by the authors.