Neutronic Evaluation of GFR Breed and Burn Fuels

Report Date: May 2023
Appendices: No

Abstract

Breed and Burn operation refers to the equilibrium operation of a fast reactor where sufficiently large amounts of plutonium are bred in-situ such that the core can be reloaded with low enrichment fuel (< 5 w/o U235) and core criticality is sustained through a discharge burnup on the order of 150 MWD/kgHM. Hence economic operation and improved uranium utilization are achieved without a requirement for reprocessing.

In the present work neutronics screening of potential nuclear fuels was carried out using a code coupling MCNP and ORIGEN. Fuel performance was measured as a function of burnup for a variety of ceramic and metallic alloy fuels.

The reactivity histories, flux spectra, and conversion ratio histories for each fuel type were evaluated and based on the results a short list of potential fuels having superior performance was developed, including: UN-15, UC, US, and U-10Zr. The neutronics studies show that high heavy metal density is a key factor in good fuel performance, which favors a metallic. For a final selection, additional evaluation must be carried out
on the basis of mechanical performance and the chemical properties of the fuel.

Program:     GFR: Gas-cooled Fast Reactors

Type:     TR 

RPT. No.: 5