Development and Demonstration of a Risk-Informed Approach to the Regulatory Required Fuel Reload Safety Analysis

Abstract

The United States (U.S.) nuclear industry is facing a strong challenge to maintain regulatory required levels of safety while ensuring economic competitiveness to stay in business. Safety remains a key parameter for all aspects related to the operation of light water reactor (LWR) nuclear power plants (NPPs) and can be achieved more economically by using a risk-informed ecosystem, such as the one being developed by the Risk-Informed Systems Analysis (RISA) Pathway under the U.S. Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) Program. The LWRS Program is promoting a wide range of research and development (R&D) activities with the goal to maximize both the safety and economically efficient performance of NPPs through improved scientific understanding, especially given that many plants are considering second license renewal.The RISA Pathway has two main goals: (1) the deployment of methodologies and technologies that enable better representation of safety margins and the factors that contribute to cost and safety; and (2) the development of advanced applications that enable cost-effective plant operation.The plant reload optimization framework development project aims to build a reactor core designing tool that integrates reactor safety and fuel performance analyses and uses artificial intelligence to support optimization of core design solutions.This report summarizes the following activities that were successfully performed in fiscal year (FY)-2022:  Enhancement of a single objective genetic algorithm (GA)-based optimization framework by applying evolution, mutation, survivor, and constraints control methods. Investigation of new experiment data and water droplet models to improve uncertainty analysis in a reflood phenomenon during a loss of coolant accident (LOCA).

Development of Plant Reload Optimization Framework Capabilities for Core Design and Fuel Performance Analysis

“…The goals of the optimized core were set to minimize both peaking factors (i.e., FΔH and FQ) and hot full power (HFP) boron concentration while maximizing cycle energy. The target constraint values for the design are FQ < 2.1, FΔH < 1.48 and HFP boron concentration <1300 ppm 1 . A single objective optimization method was used as a variable named <target>, representing the fitness function from following equation:…”

“…The United States (U.S.) Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) Program Risk-Informed Systems Analysis (RISA) Pathway Plant Reload Optimization project aims to develop an integrated, comprehensive platform offering an all-in-one solution for reactor core reload evaluations with a special focus on optimization of core design considering feedback from system safety analysis (i.e., thermal-hydraulics) and fuel performance [1].…”

“…During the core design code benchmark study by the RISA pathway, the PARCS and TRANSURANUS codes showed high degrees of flexibility and efficiency in the RISA pathway GAbased optimization platform [1].…”

Development of Genetic Algorithm Based Multi-Objective Plant Reload Optimization Platform

“…The United States (U.S.) Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) Program Risk-Informed Systems Analysis (RISA) Pathway Plant Reload Optimization Project aims to develop an integrated, comprehensive platform offering an all-in-one solution for reload evaluations with a special focus on core design optimization [1]. Fuel reload optimization is a multi-physics problem that needs to consider core design, fuel performance, and system safety.…”

“…The GA optimization platform development progressed in FY-2022 by implementing more evolutionary operations mechanisms (i.e., fitness functions, parent selection, crossover, mutation, and survivor selection) [8]. In FY-2023 the development focused on the improving the GA method for multiobjective optimization and risk-informed methodology applicability to the Plant Reload Optimization Platform.…”