ICONE11-36458 PROBABILISTIC SAFETY ASSESSMENT FOR INSTRUMENTATION AND CONTROL SYSTEMS IN NUCLEAR POWER PLANTS : A LITERATURE SURVEY

2003 ◽  
Vol 2003 (0) ◽  
pp. 430
Author(s):  
Lixuan Lu ◽  
Jin Jiang
Keyword(s):  
Control Systems ◽  
Nuclear Power ◽  
Safety Assessment ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Literature Survey ◽  
Probabilistic Safety Assessment ◽  
And Control ◽  
Probabilistic Safety

Application of Probabilistic Safety Assessment in the Design of Instrumentation and Control Systems for Nuclear Power Plants

2017 ◽  
Author(s):  
Pengyi Peng ◽  
Weidong Liu ◽  
Zhichao Yang
Keyword(s):  
Risk Assessment ◽  
Optimal Design ◽  
System Design ◽  
Nuclear Power ◽  
Safety Assessment ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Probabilistic Safety Assessment ◽  
And Control ◽  
Probabilistic Safety

Instrumentation and control (I&C) systems in nuclear power plants (NPPs) have the ability to initiate the safety-related functions necessary to shut down the plants and maintain the plants in a safe shutdown condition. I&C systems of low reliability will bring risks to the safe operation of NPPs. A sufficient level of redundancy and diversity of I&C design to ensure the safety is a major focus when designing a new reactor. Usually multiple signal paths are included in an I&C system design. Meanwhile, besides the protection and safety monitoring system (PMS), other sub-systems of I&C such as the diverse actuation system (DAS) will be included as a diverse backup of PMS to perform the functions of reactor trip and engineered safety features actuation systems (ESFAS). However, the construction costs increase as the level of system redundancy and diversity grows. In fact, from the perspective of deterministic theory, an I&C system of only two chains can meet the single failure criterion. So how to obtain the balance of safety and economy is a challenging problem in I&C system designing. Probabilistic Safety Assessment (PSA) is the most commonly used quantitative risk assessment tool for decision-making in selecting the optimal design among alternative options. In this paper, PSA technique was used to identify whether the I&C system design offers adequate redundancy, diversity, and independence with sufficient defense-in-depth and safety margins in the design of a new reactor. Firstly, detailed risk assessment criteria for I&C design were studied and identified in accordance with nuclear regulations. Secondly, different designs were appropriately modeled, and the risk insights were provided, showing the balance of safety and economy of each design. Furthermore, potential design improvements were evaluated in terms of the current risk assessment criterion. In the end, the optimal design was determined, and uncertainty analyses were performed. The results showed that all four designs analyzed in this paper were met the safety goals in terms of PSA, but each design had a different impact on the balance of risk. As the support systems of the NPP we analyzed were relatively weak, loss of off-site power and loss of service water were two main risk contributors. The common cause failure of reactor trip breakers and the sensors of containment pressure were risk-significant. After identifying the major risk factors, the I&C design team can perform subsequent optimizations in the further design based on the PSA results and achieve an optimal balance between safety and economy.

Review of the Configuration Risk Management Methodologies

2021 ◽  
Author(s):  
Yuhang Zhang ◽  
Zhijian Zhang ◽  
He Wang ◽  
Lixuan Zhang ◽  
Dabin Sun
Keyword(s):  
Risk Management ◽  
Real Time ◽  
Nuclear Power ◽  
Safety Assessment ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Probabilistic Safety Assessment ◽  
Technical Specifications ◽  
Risk Monitor ◽  
Probabilistic Safety

Abstract To ensure nuclear safety and prevent or mitigate the consequences of accidents, many safety systems have been set up in nuclear power plants to limit the consequences of accidents. Even though technical specifications based on deterministic safety analysis are applied to avoid serious accidents, they are too poor to handle multi-device managements compared with configuration risk management which computes risks in nuclear power plants based on probabilistic safety assessment according to on-going configurations. In general, there are two methodologies employed in configuration risk management: living probabilistic safety assessment (LPSA) and risk monitor (RM). And average reliability databases during a time of interest are employed in living probabilistic safety assessment, which may be naturally applied to make long-term or regular management projects. While transient risk databases are involved in risk monitor to measure transient risks in nuclear power plants, which may be more appropriate to monitor the real-time risks in nuclear power plants and provide scientific real-time suggestions to operators compared with living probabilistic safety assessment. And this paper concentrates on the applications and developments of living probabilistic safety assessment and risk monitor which are the mainly foundation of the configuration risk management to manage nuclear power plants within safe threshold and avoid serious accidents.

Fuzzy methodology applied to Probabilistic Safety Assessment for digital system in nuclear power plants

2011 ◽  
Vol 241 (9) ◽  
pp. 3967-3976 ◽  
Author(s):  
Antonio César Ferreira Guimarães ◽  
Celso Marcelo Franklin Lapa ◽  
Maria de Lourdes Moreira
Keyword(s):  
Nuclear Power ◽  
Safety Assessment ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Digital System ◽  
Probabilistic Safety Assessment ◽  
Probabilistic Safety

A Risk-Informed On-Line Test and Maintenance Framework for Redundant Instrumentation and Control Systems in Nuclear Power Plants

2004 ◽  
Author(s):  
Lixuan Lu ◽  
Jin Jiang
Keyword(s):  
Reliability Analysis ◽  
Control Systems ◽  
Nuclear Power ◽  
Safety Assessment ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Energy Market ◽  
On Line ◽  
Line Test ◽  
And Control

Deregulation forces Nuclear Power Plants (NPPs) to operate not only safely, but also more economically. Instrumentation and Control (I&C) systems in NPPs play an important role to reduce operational related costs. Therefore, a well-planned test and maintenance (T&M) strategy for I&C systems is more important then ever in this deregulated energy market. This paper presents a general T&M framework for digital I&C systems in NPPs. There are three main parts within this framework: probabilistic safety assessment (PSA), reliability analysis, and costs evaluation. PSA is used to set risk-informed unavailability limits. Reliability analysis is used to derive the relation between the unavailability and the T&M interval. Costs associated with not only T&M, but also reactor mal-shutdowns are evaluated. The Shutdown System Number One (SDSI) in Canadian Deuterium-Uranium (CANDU) based NPPs is used as an example system to illustrate the proposed framework.

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