Considerations for the Use of Probabilistic Assessments in Regulatory Decision Making Related to Pressure Boundary Component Aging

2017 ◽  
Author(s):  
Blair Carroll ◽  
John C. Jin
Keyword(s):  
Decision Making ◽  
Boundary Component ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Informed Decision ◽  
Informed Decision Making ◽  
Regulatory Decision ◽  
Plant Safety ◽  
Unintended Effect ◽  
The Impact

Within the current Canadian regulatory framework, the structural integrity of pressure boundary components with detected service-induced degradation must be demonstrated using deterministic evaluation techniques. However, Canadian Nuclear Safety Commission staff has recognized that the inherent conservatism in these deterministic assessment approaches may generate overly conservative conclusions when they are applied to assess the impact of postulated service-induced degradation to establish aging management requirements for nuclear power plant pressure boundary components. This may have the unintended effect of reducing the effectiveness of aging management programs by directing resources towards activities that will have minimal benefit on improving plant safety and could result in unnecessary dose to personnel. With this in mind, CNSC staff has accepted the limited use of probabilistic assessments prepared by licensees to support aging management activities for pressure boundary components. These probabilistic assessments form a part of risk-informed decision making strategies intended to reduce excess conservatism that could arise if decisions are based solely on the results of deterministic assessments. This paper provides an overview of CNSC staff’s experiences with the review and acceptance of licensee submissions incorporating probabilistic assessments of pressure boundary component aging for risk informed decision making.

The Application of Risk-Informed Decision-Making Approach in Optimization of Allowed Outage Time for Safety System in Nuclear Power Plant

2017 ◽  
Author(s):  
Licun Wu ◽  
Chao Ma ◽  
Wei Deng
Keyword(s):  
Decision Making ◽  
High Pressure ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Safety System ◽  
Informed Decision ◽  
Informed Decision Making ◽  
Deterministic Analysis ◽  
The Impact

To facilitate online maintenance for High Pressure Safety Injection (HPSI) system in nuclear power plant, the optimization measure for Allowed Outage Time (AOT) is proposed in this paper, and risk-Informed decision-making approach is used to demonstrate its feasibility. According to the analysis results, the extension of AOT meets the requirements of relative guides and deterministic analysis, and the impact on risk of plant is acceptable. Based on the extension of AOT, it is feasible to carry out online maintenance for safety system and corresponding support systems, which can effectively reduce workload during shutdown.

A Risk-Informed Decision Making Methodology for Evaluating Failure Impact of Early System Designs

2008 ◽  
Author(s):  
Tolga Kurtoglu ◽  
Irem Y. Tumer
Keyword(s):  
Decision Making ◽  
System Development ◽  
Informed Decision ◽  
System Level ◽  
Analysis Tool ◽  
Informed Decision Making ◽  
Simulation Based ◽  
System Risk ◽  
Guide System ◽  
The Impact

In this paper, we introduce a new risk-informed decision-making methodology for use during early design of complex systems. The proposed approach is based on the notion that a failure happens when a functional element in the system does not perform its intended task. Accordingly, risk is defined depending on the role of functionality in accomplishing designed tasks. A simulation-based failure analysis tool is used to analyze functional failures and their impact on overall system functionality. The analysis results are then integrated into a decision-making framework that relates the impact of functional failures and their propagation to decision making in order to guide system level design decisions. With the help of the proposed methodology, a multitude of failure scenarios can be quickly analyzed to determine the effects of decisions on overall system risk. Using this decision-making approach, design teams can systematically explore risks and vulnerabilities during early, functional stage of system development prior to the selection of specific components. Application of the presented method to a reservoir system design demonstrates these capabilities.

scholarly journals Global Methodology for Electrical Utilities Maintenance Assessment Based on Risk-Informed Decision Making

2021 ◽  
Vol 13 (16) ◽  
pp. 9091
Author(s):  
Mohamed Gaha ◽  
Bilal Chabane ◽  
Dragan Komljenovic ◽  
Alain Côté ◽  
Claude Hébert ◽  
...  
Keyword(s):  
Decision Making ◽  
Asset Management ◽  
Electrical Power ◽  
Informed Decision ◽  
Informed Decision Making ◽  
Power Utility ◽  
Important Indicator ◽  
Power Utilities ◽  
The Impact ◽  
Electrical Utilities

Modern electrical power utilities must deal with the replacement of large portions of their assets as they reach the end of their useful life. Their assets may also become obsolete due to technological changes or due to reaching their capacity limits. Major upgrades are also often necessary due to the need to grow capacity or because of the transition to more efficient and carbon-free power alternatives. Consequently, electrical power utilities are exposed to significant risks and uncertainties that have mostly external origins. In this context, an effective framework should be developed and implemented to maximize value from assets, ensure sustainable operations and deliver adequate customer service. Recent developments show that combining the concepts of asset management and resilience offers strong potential for such a framework—not only for electrical utilities, but for industry, too. Given that the quality and continuity of service are critical factors, the concept of Value of Lost Load (VoLL) is an important indicator for assessing the value of undelivered electrical energy due to planned or unplanned outages. This paper presents a novel approach for integrating the power grid reliability simulator into a holistic framework for asset management and electrical power utility resilience. The proposed approach provides a sound foundation for Risk-Informed Decision Making in asset management. Among other things, it considers asset performance as well as the impact of both current grid topology and customer profiles on grid reliability and VoLL. A case study on a major North American electrical power utility demonstrates the applicability of the proposed methodology in assessing maintenance strategy.

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