Valuation of accident tolerant fuel for industry adoption: ATF valuation 2.0

Currently licensed fuel designs in the majority of light water reactors (LWRs) utilize uranium dioxide (UO2) fuel enclosed within a zirconium alloy (zircaloy) cladding. Years of research accompanied by 60 years of commercial reactor operational experience have optimized these fuels to achieve economic and safe operation of the current nuclear plant fleet. The events at the Fukushima Daiichi nuclear power generating station coupled with recent material advancements have provided a strong motivation for the nuclear power industry, academia, and national laboratories to develop and transition to new fuel designs with an emphasis on improving safety, performance, and reliability for expected operating and postulated accident conditions. However, for these advanced fuels to achieve widespread adoption by the current fleet of operating plants, these fuels will need to provide additional safety and economic benefits over current fuels. In a companion paper we described initial industry activities that were performed to assess the safety and operational capabilities of advanced fuels (with particular focus on accident tolerant fuel (ATF) concepts) and the timeframe for development, licensing, and testing that would be necessary to achieve industry needs to permit their widespread deployment. These evaluations were characterized as ATF Valuation 1.0. In this paper we describe results from subsequent detailed evaluations sponsored by the Electric Power Research Institute related to the benefits that ATF can provide (referred to as ATF Valuation 2.0). ATF Valuation 2.0 evaluations were conducted in a collaborative manner that included a broad range of industry stakeholders including nuclear fuel vendors, nuclear plant owner/operators, and industry service providers. In this paper we provide results for the analysis of performance under severe accident conditions (i.e. beyond design basis events) for various ATF concepts. Key event sequences for both BWR and PWR plants are assessed. Additionally, we provide results and insights into the risk enhancements that can be provided by the various ATF concepts that are undergoing active development.