Extended Burnup Fuel Cycle Optimization for Pressurized Water Reactors

Abstract

A fast, yet accurate, fuel cycle analysis methodology was developed to optimize the various options for in-core nuclear fuel management. The methodology encompasses two major parts, a multicycle point reactor model, PUFLAC, and a reload pattern optimization code called DSPWR. The PUFLAC model provides a convenient and reliable survey ability to explore the various fuel cycle scheme possibilities while DSPWR utilizes a direct search scheme to minimize the core power peaking with consideration given to local power-peaking factor variation. A two-dimensional nodal code used in this direct search scheme was developed for the power distribution calculations and is based on the widely used code, EPRI-NODE-P, with very good agreement obtained.

This methodology has been demonstrated by considering an extended burnup three-to-four batch transition cycle analysis using Zion Unit 1 as a reference pressurized water reactor plant with realistic power-peaking constraints. The four-batch scheme can yield an increase in uranium utilization of ~5% and a decrease in fuel cycle costs of ~7%. The transition from a three to four-batch scheme can yield an overall increase in uranium utilization of 2.4% and a decrease in fuel cycle costs of ~4%. The transition fuel-loading patterns optimized by DSPWR satisfy the core power-peaking constraint with a 2 to 3% margin at beginning-of-cycle.