PSAM 16 - Session W04 Overview

PSAM 16 Conference Session W04 Overview

Session Chair: Antonios Zoulis (antonios.zoulis@nrc.gov)

Paper 1 LU292

Lead Author: Lukasz Sokolowski

Assessment of Input Errors in Schedule Risk Analysis (SRA) of Multidisciplinary Projects
Schedule Risk Analysis (SRA) results of multidisciplinary projects can be influenced by multiple factors. This paper presents an assessment and examples of most relevant input errors related to input data collection, planning and arrangement of the SRA process in the project structure and errors in quantitative computations. Regarding the input data collection recommendations are provided on choosing relevant risk categories, creating a supportive climate for project members so that they are ready to provide a reliable input and on how a country or region's institutions (authorities, history, tradition) might influence the decision making process. The arrangement of the SRA process in the projects is on creating the process so that it delivers the accurate results without compromising the personnel performance. When it comes to the quantitative computations the author gives some thoughts on which variables are most crucial and useful as input, how to perform the computations as well as compute and properly analyze Cumulative Distribution Function (CDF) diagram. In the paper a special focus is put on the relevance and quality of bottom-up (specialists, technicians) and top-down (top managers) inputs in risk-informed decision making support.

Assessment of Input Errors in Schedule Risk Analysis (SRA) of Multidisciplinary Projects

Schedule Risk Analysis (SRA) results of multidisciplinary projects can be influenced by multiple factors. This paper presents an assessment and examples of most relevant input errors related to input data collection, planning and arrangement of the SRA process in the project structure and errors in quantitative computations. Regarding the input data collection recommendations are provided on choosing relevant risk categories, creating a supportive climate for project members so that they are ready to provide a reliable input and on how a country or region's institutions (authorities, history, tradition) might influence the decision making process. The arrangement of the SRA process in the projects is on creating the process so that it delivers the accurate results without compromising the personnel performance. When it comes to the quantitative computations the author gives some thoughts on which variables are most crucial and useful as input, how to perform the computations as well as compute and properly analyze Cumulative Distribution Function (CDF) diagram. In the paper a special focus is put on the relevance and quality of bottom-up (specialists, technicians) and top-down (top managers) inputs in risk-informed decision making support.

Paper LU292 | | Download the presentation PowerPoint file.

Name: Lukasz Sokolowski (lukasz.sokolowski@kiwa.com)

Bio: I support clients in decision-making processes by setting up suitable risk routines, conducting risk workshops and perform computations. I specialize myself in qualitative and quantitative risk analyses and I perform Schedule Risk Assessment (SRA) for a variety of industries as nuclear, process industry, pulp & paper and healthcare. My professional interest related to risk analysis lies in influence of human factors and institutions on results of the quantitative risk analysis.

Country: SWE
Company: Kiwa Sweden
Job Title: Risk Engineer

Paper 2 DI118

Lead Author: Diego Mandelli Co-author(s): C. Wang: Congjian.Wang@inl.gov S. Lawrence: Svetlana.Lawrence@inl.gov D. Morton: david.morton@northwestern.edu I. Popova: ivilina.popova@gmail.com S. Hess: SHess@jensenhughes.com

Bridging equipment reliability data and risk informed decisions in a plant operation context
Industry equipment reliability and asset management programs are essential elements that help ensure the safe and economical operation of nuclear power plants. The effectiveness of these programs is addressed in several industry-developed and regulatory programs. The Risk-Informed Asset Management (RIAM) project is tasked to develop tools in support of the equipment reliability and asset management programs at nuclear power plants. These tools are designed to create a direct bridge between component health/lifecycle data and decision making (e.g., maintenance scheduling and project prioritization). The goal of this article is to provide a guide for specific use cases that the RIAM project is targeting. We have grouped uses cases into three main areas. The first area focuses on the analysis of equipment reliability data with a particular emphasis on condition-based data, such as test/surveillance reports and component monitoring data. The second area focuses on the integration of equipment reliability into system/plant reliability models to determine system/plant health and identify the components that are critical to maintain an operational system. Lastly, the third area manages plant resources, such as maintenance activities and replacement scheduling using optimization methods. Here the primary focus is on supporting typical system engineer decisions regarding maintenance activity scheduling and component aging management. This is performed in a risk-informed context where the term “risk” is broadly constructed to include both plant reliability and economics. This framework combines data analytics tools to analyze equipment reliability data with risk-informed methods designed to support system engineer decisions (e.g., maintenance and replacement schedules, optimal maintenance posture) in a customizable workflow.

Bridging equipment reliability data and risk informed decisions in a plant operation context

Industry equipment reliability and asset management programs are essential elements that help ensure the safe and economical operation of nuclear power plants. The effectiveness of these programs is addressed in several industry-developed and regulatory programs. The Risk-Informed Asset Management (RIAM) project is tasked to develop tools in support of the equipment reliability and asset management programs at nuclear power plants. These tools are designed to create a direct bridge between component health/lifecycle data and decision making (e.g., maintenance scheduling and project prioritization). The goal of this article is to provide a guide for specific use cases that the RIAM project is targeting. We have grouped uses cases into three main areas. The first area focuses on the analysis of equipment reliability data with a particular emphasis on condition-based data, such as test/surveillance reports and component monitoring data. The second area focuses on the integration of equipment reliability into system/plant reliability models to determine system/plant health and identify the components that are critical to maintain an operational system. Lastly, the third area manages plant resources, such as maintenance activities and replacement scheduling using optimization methods. Here the primary focus is on supporting typical system engineer decisions regarding maintenance activity scheduling and component aging management. This is performed in a risk-informed context where the term “risk” is broadly constructed to include both plant reliability and economics. This framework combines data analytics tools to analyze equipment reliability data with risk-informed methods designed to support system engineer decisions (e.g., maintenance and replacement schedules, optimal maintenance posture) in a customizable workflow.

Paper DI118 | Download the paper file. |

Name: Diego Mandelli (diego.mandelli@inl.gov)

Bio:

Country: USA
Company: Idaho National Laboratory
Job Title: R&D Scientist

Paper 3 YI80

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.

Paper YI80 | Download the paper file. |

Name: 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: USA
Company: Argonne National Lab
Job Title: Nuclear Engineer

Paper 4 MA213

Lead Author: Marina Roewekamp Co-author(s): Joshua Gordon, Office for Nuclear Regulation (ONR), United Kingdom Christian Müller, Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH, Germany

Recent Tasks of the OECD Nuclear Energy Agency Working Group WGRISK – An Overview
Overall objective of the OECD Nuclear Energy Agency (NEA) Working Group on Risk Assessment (WGRISK) is to permanently advance and extend the understanding of probabilistic safety assessment (PSA ). and facilitate its use and application as an important tool for nuclear safety assessment. WGRISK therefore conducts a variety of activities for risk related information exchange between member countries` experts enhancing the use of this tool in order to improve safety. In the recent past, WGRISK has successfully completed an activity on “Comparative Application of DIGital I&C Modelling Approaches for PSA (DIGMAP)”. A follow-on activity titled “DIGMORE – A Realistic Comparative Application of DI&C Modelling Approaches for PSA” aiming on supporting the improvement of the probabilistic assessment methodology by providing guidance for PSAs with respect to digital I&C (DI&C) systems (including relevant aspects of their hardware and software). Other currently ongoing or to be started activities are the following: - “PSA for Reactor Facilities of a Singular Design”, where a workshop shall be organized in early 2022 for exchanging experiences from and practices for performing PSAs for reactor facilities such as first-of-a-kind, prototype or demonstration, and research reactors, - “PSA for Reactor Facilities of a Singular Design”, where a symposium will be organized in early 2022 for exchanging experiences from and practices for performing PSAs for reactor facilities such as first-of-a-kind, prototype or demonstration, and research reactors, - “Dynamic PSA – Preparing for the Future” addressing the potential for dynamic PSA in risk-informed decision-making (RIDM) as well as feasibility and practical challenges for increased adoption of dynamic PSA, - “Combinations of External Hazards – Hazard and Impact Assessment and Probabilistic Safety Analysis (PSA) for Nuclear Installations” as a joint activity of WGRISK and the Working Group on External Events (WGEV) (see separate paper) initiated in 2020 addressing the state-of-the-art in considering combinations of external hazards in the design and safety assessment of nuclear installations, - “Use and Development of PSA – Status Report”, a standard WGRISK task conducted about every five years in order to provide a report on the status of actual developments and applications of the PSA tool in member countries, and - “Treatment of Uncertainties for New and Advanced Reactors” intended to be started in summer 2022 in order to get a better understanding how – in light of several types of new and advanced reactors being built in WGRISK member countries – uncertainties in probabilistic risk assessment for these reactors are considered and treated. This paper presents an overview on the ongoing and envisioned activities of the WGRISK.

Recent Tasks of the OECD Nuclear Energy Agency Working Group WGRISK – An Overview

Overall objective of the OECD Nuclear Energy Agency (NEA) Working Group on Risk Assessment (WGRISK) is to permanently advance and extend the understanding of probabilistic safety assessment (PSA ). and facilitate its use and application as an important tool for nuclear safety assessment. WGRISK therefore conducts a variety of activities for risk related information exchange between member countries` experts enhancing the use of this tool in order to improve safety. In the recent past, WGRISK has successfully completed an activity on “Comparative Application of DIGital I&C Modelling Approaches for PSA (DIGMAP)”. A follow-on activity titled “DIGMORE – A Realistic Comparative Application of DI&C Modelling Approaches for PSA” aiming on supporting the improvement of the probabilistic assessment methodology by providing guidance for PSAs with respect to digital I&C (DI&C) systems (including relevant aspects of their hardware and software). Other currently ongoing or to be started activities are the following: - “PSA for Reactor Facilities of a Singular Design”, where a workshop shall be organized in early 2022 for exchanging experiences from and practices for performing PSAs for reactor facilities such as first-of-a-kind, prototype or demonstration, and research reactors, - “PSA for Reactor Facilities of a Singular Design”, where a symposium will be organized in early 2022 for exchanging experiences from and practices for performing PSAs for reactor facilities such as first-of-a-kind, prototype or demonstration, and research reactors, - “Dynamic PSA – Preparing for the Future” addressing the potential for dynamic PSA in risk-informed decision-making (RIDM) as well as feasibility and practical challenges for increased adoption of dynamic PSA, - “Combinations of External Hazards – Hazard and Impact Assessment and Probabilistic Safety Analysis (PSA) for Nuclear Installations” as a joint activity of WGRISK and the Working Group on External Events (WGEV) (see separate paper) initiated in 2020 addressing the state-of-the-art in considering combinations of external hazards in the design and safety assessment of nuclear installations, - “Use and Development of PSA – Status Report”, a standard WGRISK task conducted about every five years in order to provide a report on the status of actual developments and applications of the PSA tool in member countries, and - “Treatment of Uncertainties for New and Advanced Reactors” intended to be started in summer 2022 in order to get a better understanding how – in light of several types of new and advanced reactors being built in WGRISK member countries – uncertainties in probabilistic risk assessment for these reactors are considered and treated. This paper presents an overview on the ongoing and envisioned activities of the WGRISK.

Paper MA213 | Download the paper file. | Download the presentation pdf file.

Name: Marina Roewekamp (Marina.Roewekamp@grs.de)

Bio: - Diploma in Physics PhD (Dr. rer. nat. In Physical Chemistry / Materials Science) from University of Bonn - Senior Chief Expert for Hazards and PSA at GRS – the Federal German Nuclear Technical Safety Organization – for > 33 years - PSA work: mainly performing and/or reviewing Level 1 PSA, particularly for Internal and External Hazards (incl. hazard combinations) - Member of the German PSA Expert Panel for > 15 years - Former Chair and actual Vice Chair of OECD/NEA/CSNI Working Group on Risk Assessment (WGRISK) - Chair of OECD/NEA CSNI Expert Group on Fire Risk (EGFR) and of Management Board of OECD/NEA FIRE (Fire Events Records Exchange) Project - Consultant and/or reviewer for various IAEA Guides (SSG-64, SSG-67, SSG-68, DS523 (revision of SSG-3 on Level 1 PSA), DS528 (revision of SSG-4 on Level 2 PSA), TECDOCS on MUPSA, Advanced PSA Methods, Safety Assessment of Nuclear Installations Against Combinations of External Hazards, etc. - IAPSAM Board of Directors member since

Country: DEU
Company: Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH
Job Title: Chief Senior Expert