OPTIMIZING THE OUTAGE REFUELING TIME WITH SHUFFLE CONSCIOUS CORE DESIGN EVALUATION VIA ePROMETHEUS?

摘要

This paper introduces outage refueling time optimization methodology developed at GNF based on Shuffle Conscious Core Design Evaluation and presents the benchmark problem results for typical reference BWR core designs with different core loading schema, energy plans and batch requirements. ePrometheus? GNF Fuel Cycle Optimization Tool has been upgraded and a new prototype has been developed to include outage refueling time constraint parameter in the optimization objective function component. The objective is to minimize outage refueling time during core design optimization search without compromising from the energy optimized core design performance. Shuffle Conscious Core Design Evaluation proactively considers meeting outage maintenance configuration requirements and eliminating possible shuffle related problems during the core design phase that will also help outage team by providing improvement in shuffling sequence planning later. All benchmark cases started with a reference energy optimized core design that was designed to meet all cycle energy requirements and thermal limits without considering outage refueling time parameter. Three benchmarks studies were performed with the following scenarios: 1) Benchmark Ⅰ - Typical mid-size BWR core with 580 bundles in the core and utilizing same fresh fuel locations between cycles with 26 % fresh batch percentage, 2) Benchmark Ⅱ - BWR core with 764 bundles in the core with (24 % fresh batch percentage and alternating the fresh fuel locations between the cycles (hot to cold centered core loading), and 3) Benchmark Ⅲ - BWR core with 764 bundles in the core that has a EPU (Extended Power Upgrade) plan and high fresh batch fraction (50 %) requirement. It was demonstrated that 8.4 hours outage refueling time savings was possible with the optimization for Benchmark Ⅰ. For Benchmark Ⅱ including alternating fresh fuel locations in the core design provided 16.2 hours outage refueling time savings, which 10 hours savings directly resulted from finding 19 % not-move bundle fraction in the optimization search with the help of alternating the fresh fuel locations. Benchmark Ⅲ provided only 4.8 hours outage refueling time savings due to high batch fraction EPU core design and limited opportunities for improving shuffling process in the optimization process.