Research on Nuclear Power Plant Safety Functional Requirements Analysis and Function Allocation

2018 ◽  
Author(s):  
Jia Ming ◽  
Huang Huan ◽  
Zhang Xuegang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Requirements Analysis ◽  
Injection System ◽  
Design Stage ◽  
Functional Requirements ◽  
System Configuration ◽  
System Components ◽  
Safety Features

This paper researched the safety functional requirements analysis and the allocation of functions between man and machine for the nuclear power plant. The safety functional requirements are identified from accident handling needs and refined from system configuration consideration. Through the analysis of design conditions, some safety features were extracted to mitigate accidents. Then, components (e.g. pumps, valves, tanks) were determined to implement each of the safety features at the system design stage. At this stage, some implicit safety features, which could not be obtained directly from the accident analysis, were added, according to the specific conditions of system configuration and operation. Finally, after further judgement on possible inconsistency, a complete list of safety functions for the nuclear power plant was formed. As an illustration, this paper provided a list of safety functions related to the safety injection function, and a list of equipment for the safety injection system. Furthermore, these identified safety functions, were appropriately allocated between man and machine, to be performed either by system components automatically, or by operators locally or remotely from the control room, or under the cooperation of operators and system components. Seven factors were considered in the allocation: a) performance requirements; b) the capability or limits of man and machine; c) existing practices; d) operating experience; e) management requirement; f) technical feasibility; g) cost. The allocation of functions for the safety injection system was validated using a simulator.

Safety Study of Primary Loop System of Civil Marine Nuclear Power Plant

2014 ◽  
Vol 541-542 ◽  
pp. 916-921 ◽  
Author(s):  
Li Xu ◽  
Ru Chao Deng ◽  
Chu Xu ◽  
Di Zhang ◽  
Chen Xing Sheng
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Comprehensive Evaluation ◽  
Environmental Parameters ◽  
Loop System ◽  
Injection System ◽  
Safety Study ◽  
Primary Loop ◽  
Control Rods

For evaluate the risk of civil marine nuclear power plant, through the searching related standards for ship, external environmental parameters that the nuclear ship should be suited was found. Based on the characteristics of power plant of civil nuclear-powered ship, the hierarchy system of primary loop system was established and corresponding indicator marking criteria were formulated for the risk assessment. The result shows that the Reactor Safety Injection System (RIS), the Reactor Boron and the Water Supply System (REA), the Control Rods and the Hull of Fuel Canning are the key risk factors in the primary loop system. Finally, the comprehensive evaluation was carried out for collision, stranding and swing of multi-degree of freedom, and put forward relative countermeasures to cope with the possible risks based on the comprehensive evaluation and combined with the literatures.

Valves Maintainability Study on Nuclear Power Plant Design Stage

2017 ◽  
pp. 307-313
Author(s):  
Xiaohu Yang ◽  
Jiao Deng ◽  
Hong Jiang ◽  
Lifei Yang ◽  
Wen Chen
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Design Stage ◽  
Plant Design

Accident at Fukushima Dai-Ichi Nuclear Power Plant: Lessons Learned for the Czech Republic

2014 ◽  
Author(s):  
Ladislav Vesely ◽  
Vaclav Dostal
Keyword(s):  
Czech Republic ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Human Performance ◽  
Lessons Learned ◽  
Injection System ◽  
Human Errors ◽  
The Czech Republic ◽  
Main Error

Accident at Fukushima Dai-Ichi nuclear power plant significantly affected the nuclear industry at time when everybody was expecting the so called nuclear renaissance. There is no question that the accident has at least slowed it down. Research into this accident is taking place all over the world. In this paper we present the findings of research on Fukushima nuclear power plant accident in relation to the Czech Republic. The paper focuses on the analysis of human performance during the accident. Lessons learned from the accident and main human errors are presented. First the brief factors affecting the human performance are discussed. They are followed by the short description of activities on units 1–3. The key human errors in the accident mitigation are then identified. On unit 1 the main error is wrong understanding and operation of isolation condenser. On unit 2 the main errors were unsuccessful depressurization with subsequent delay of coolant injection. On unit 3 the main error is the shutdown of high pressure cooling injection system without first confirming that different means of cooling are available. These errors lead to fuel damage. On unit 1 the fuel damage was probably impossible to prevent, however on unit 2 and 3 it could be probably prevented. The lessons learned for the Czech Republic were presented. They can be summarizes as follows: be sure that plant personnel can and knows how to monitor and operate the crucial plant components, be sure that the procedures on how to fulfill the critical safety functions are available in the symptomatic manner for situations when there is no power available at the plant, train personnel for these situations and have sufficient human resource available for these situations.

Level 2 PSA Overview of HPR1000 Nuclear Power Plant

2020 ◽  
Author(s):  
Wang Ziguan ◽  
Lu Fang ◽  
Yang Benlin ◽  
Chen Shi ◽  
Hu Lingsheng
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Heat Removal ◽  
Accident Prevention ◽  
Severe Accident ◽  
Mitigation Measures ◽  
Injection System ◽  
Risk Level ◽  
Level 2

Abstract Risk-informed design approaches are comprehensively implemented in the design and verification process of HPR1000 nuclear power plant. Particularly, Level 2 PSA is applied in the optimization of severe accident prevention and mitigation measures to avoid the extravagant redundancy of system configurations. HPR1000 preliminary level 2 PSA practices consider internal events of the reactor in the context of at-power condition. Severe accidents mitigation and prevention system and its impact on the overall large release frequency (LRF) level are evaluated. The results showed that severe accident prevention and mitigation systems, such as fast depressurization system, the cavity injection system and the passive containment heat removal system perform well in reducing LRF and overall risk level of HPR1000 NPP. Bypass events, reactor rapture events, and the containment bottom melt-through induced by MCCI are among the dominant factors of the LRF. The level 2 PSA analysis results indicate that HPR1000 design is reliable with no major weaknesses.

Application of Level 2 PSA in the Design of Cavity Injection System for Nuclear Power Plant

2018 ◽  
Author(s):  
Wentao Zhu ◽  
Wenjing Li
Keyword(s):  
Decision Making ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Assessment Tool ◽  
Quantitative Risk Assessment ◽  
Severe Accident ◽  
Injection System ◽  
Retention Strategy ◽  
Level 2

After Fukushima nuclear power plant accident, severe accident is getting more and more concerns all over the world. In order to mitigate severe accident and improve the safety of nuclear power plant, two different strategies are applied in different plants. One is in-vessel melt retention strategy, and the other is ex-vessel melt retention strategy. Tianwan nuclear power plant is an improved Gen II nuclear power plant and in-vessel melt retention strategy is adopted in the plant. In order to achieve this strategy, cavity injection system is designed for the plant. Probabilistic Safety Analysis is the most commonly used quantitative risk assessment tool for decision-making in selecting the optimal design among alternative options. For this plant, in order to optimize the design of cavity injection system, improve the safety level of nuclear power plant, and meanwhile, improve the engineering implementation and economization, Level 2 PSA was used for this decision-making process. In this paper, the Level 2 PSA for this plant and the application for the design of cavity injection system are introduced.

Engineered Security Measures of Nuclear Power Plants

2003 ◽  
Author(s):  
F. J. Moody
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Human Error ◽  
Mechanical Damage ◽  
Thermal Hydraulics ◽  
Plant Design ◽  
Security Measures ◽  
Safety Features

Even in the absence of depraved terrorist threats, nuclear plants have been designed to respond safely to postulated accidents. Redundant safety features are built into plants to trigger safe shutdown and containment of possible accidents. The defined accidents range from minor leakage and operator errors to a complete loss of coolant from the reactor. Post-accident scenarios are postulated by experts in reactor and containment thermal-hydraulics, and all other sciences embraced by nuclear power plant design. The probability of failure is determined for all engineered safety systems. Then analytical and experimental programs are employed to predict the long term post-accident thermal-hydraulic state of a plant and its effect on the environment. The postulated accidents and safety system responses include effects resulting from mechanical damage and component malfunctions, such as pipe ruptures and the failure of pumps and valves. The initiating causes can be material failure, human error, and environmental effects from earthquakes, floods, and other severe acts of nature. It is prudent to build on an already established safety and accident technology to include the effects of external, planned attacks on a nuclear plant. This process includes “matching wits” with the minds of those who plot evil, and reinforcing protective security barriers where potential vulnerabilities are detected. Hard questions to ask and answer are, “What are the greatest potential security threats to a nuclear power plant? What possible human activity could make them happen? How can they be prevented?” Reactor and containment thermal-hydraulics contributes significantly to answering these questions.

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