Discrete Transfer Cross-Section Expansion for Time-Dependent Neutron Transport

A new discrete neutron transfer cross-section technique has been developed to resolve difficulties found using the traditional Legendre polynomial expansion for time-dependent problems with strong source anisotropy. An important class of such problems is the analysis of blanket performance in inertial confinement fusion (ICF) systems. The new technique can be readily incorporated without formal changes into existing codes that solve the transport equation. A shielding problem and an ICF blanket problem are used as examples to illustrate both the difficulties presented by the traditional approach and the improvements brought about with the new method.