PSAM 16 - Paper Overview

PSAM 16 Conference Paper Overview

Welcome to the PSAM 16 Conference paper and speaker overview page.

Lead Author: Ben Chen Co-author(s): David Grabaskas, dgrabaskas@anl.gov Richard Denning, denningrs.8@gmail.com

The Regulatory Treatment of Low Frequency External Events: Initial Insights
To assist the developing advanced reactor industry in future licensing efforts, the DOE Advanced Reactor Demonstration Program (ARDP) Regulatory Development area initiated a project at Argonne National Laboratory to examine the regulatory treatment of external hazards as part of a risk-informed performance-based (RIPB) licensing framework. A RIPB licensing framework for advanced reactors built on establishing an affirmative safety case offers the benefits of increased flexibility regarding key design and licensing decisions based on a detailed assessment and understanding of plant risk. Historically, reactor licensing addressed events of very low frequency primarily through the application of design margin and defense-in-depth (DID) philosophy. In contrast, RIPB approaches attempt to evaluate these scenarios at a level of detail commensurate with their risk, which often necessitates an explicit treatment of their frequency and associated consequence. While the detailed analysis of low frequency events provides insights that can help justify alternative treatments to past conservatism, the findings are dependent on the quality and confidence associated with the analyses. The assessment of external hazards presents a unique challenge, as their potential frequency of occurrence, especially of large magnitude events, is inherently uncertain given the long return periods in question. This project aims to identify the benefits and challenges of such approaches for advanced reactor vendors and aid in the development of consistent and appropriate analysis methodologies. The paper summarizes initial project findings, focusing on the evaluation of the seismic hazard. This includes an exploration of the implementation of a RIPB approach through an example analysis. The probabilistic approach to the assessment of external hazards requires a convolution of the hazard curve and fragilities of the structures, systems, and components (SSCs) within the plant. Due to the increasing uncertainty regarding the hazard curve estimate at low frequencies, the analysis findings were primarily driven by the uncertainty in the hazard curve. Based on the findings of this assessment, additional performance-based methods were explored as potential complementary approaches, such as a PRA-based seismic margins approach. This paper highlights key challenges and opportunities associated with the methods and outlines future steps to assist with their implementation.

The Regulatory Treatment of Low Frequency External Events: Initial Insights

To assist the developing advanced reactor industry in future licensing efforts, the DOE Advanced Reactor Demonstration Program (ARDP) Regulatory Development area initiated a project at Argonne National Laboratory to examine the regulatory treatment of external hazards as part of a risk-informed performance-based (RIPB) licensing framework. A RIPB licensing framework for advanced reactors built on establishing an affirmative safety case offers the benefits of increased flexibility regarding key design and licensing decisions based on a detailed assessment and understanding of plant risk. Historically, reactor licensing addressed events of very low frequency primarily through the application of design margin and defense-in-depth (DID) philosophy. In contrast, RIPB approaches attempt to evaluate these scenarios at a level of detail commensurate with their risk, which often necessitates an explicit treatment of their frequency and associated consequence. While the detailed analysis of low frequency events provides insights that can help justify alternative treatments to past conservatism, the findings are dependent on the quality and confidence associated with the analyses. The assessment of external hazards presents a unique challenge, as their potential frequency of occurrence, especially of large magnitude events, is inherently uncertain given the long return periods in question. This project aims to identify the benefits and challenges of such approaches for advanced reactor vendors and aid in the development of consistent and appropriate analysis methodologies. The paper summarizes initial project findings, focusing on the evaluation of the seismic hazard. This includes an exploration of the implementation of a RIPB approach through an example analysis. The probabilistic approach to the assessment of external hazards requires a convolution of the hazard curve and fragilities of the structures, systems, and components (SSCs) within the plant. Due to the increasing uncertainty regarding the hazard curve estimate at low frequencies, the analysis findings were primarily driven by the uncertainty in the hazard curve. Based on the findings of this assessment, additional performance-based methods were explored as potential complementary approaches, such as a PRA-based seismic margins approach. This paper highlights key challenges and opportunities associated with the methods and outlines future steps to assist with their implementation.

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Author and Presentation Info

Lead Author Name: Yichao (Ben) Chen (yichao.chen@anl.gov)

Bio: Ben has experience working with multiple LWR fleets developing risk-informed applications across the US, working with PRA models of various plant sites, and more recently has been involved in a number of projects regarding the developing field of advanced reactor licensing and regulations under the Safety and Risk Assessment Group at Argonne National Laboratory. Ben is a member of the ANS/ASME Joint Committee on Nuclear Risk Management (JCNRM), and holds a Bachleor's Degree in Nuclear Engineering from the University of Wisconsin-Madison.

Country: United States of America
Company: Argonne National Lab
Job Title: Nuclear Engineer

PSAM 16 Conference Paper Overview

Welcome to the PSAM 16 Conference paper and speaker overview page.

Paper YI80 Preview

Author and Presentation Info

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