Evaluation of the core physics and safety characteristics of a quasi-homogeneous LMFBR concept

A core design concept utilizing two types of driver assemblies that differ in fuel pin diameter has been investigated as an alternative to the heterogeneous LMFBR core for achieving low HCDA energetics. Core designs based on the (quasi-homogeneous) concept were developed and their performance compared to that of standard homogeneous and hetergeneous cores. It is shown that quasi-homogenous cores can be designed which possess many of the performance advantages of homogeneous cores (such as reduced power mismatches and local power swings), while retaining the potential safty advantages of heterogeneous cores (such as an incoherent response during loss-of-flow accidents and a reduced coolant void reactivity worth)