Research on Probabilistic Safety Assessment (PSA) Method of Safety Class Distributed Control System (DCS) in Nuclear Power Plant Based on Fuzzy Markov Process

2020 ◽  
Author(s):  
Tian Xufeng ◽  
Yan Hao
Keyword(s):  
Control System ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Markov Process ◽  
Distributed Control ◽  
Nuclear Power ◽  
Safety Assessment ◽  
Fault Tree ◽  
Simulation Method ◽  
Distributed Control System

Abstract Safety class DCS (Distributed Control System) in nuclear power plant is characterized by multi-state interaction, complex function and unknown fault mechanism, which limits the use of tradition PSA (Probabilistic Safety Assessment) method such as event tree and fault tree. An improved dynamic probabilistic security simulation method is proposed based on fuzzy Markov process to quantitative evaluation the risk of Safety class DCS in nuclear power plant, which resolved the failure uncertainty problem without in-depth understanding of failure mechanism. Firstly, the fuzzy fault tree reliability evaluation model is established based on fuzzy theory and FTA (Fault Tree Analysis), which describes the probability and degree of failure with fuzzy number. Then, the fuzzy fault tree is transformed into fuzzy Markov chain, this model is described mathematically, and the reliability indexes are simulated and analyzed with Monte Carlo simulation method, the change of system safety performance in long-term operation is obtained. Finally, the scientificity and effectiveness is verified by the example of redundant analog output module of safety class DCS in nuclear plant.

A Nuclear Power Plant Distributed Control System

1997 ◽  
Vol 30 (18) ◽  
pp. 391-396
Author(s):  
Mathilde Aimar ◽  
Gilles Arnaud ◽  
Michel Dumas
Keyword(s):  
Control System ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Distributed Control ◽  
Nuclear Power ◽  
Distributed Control System

Study on Reliability Analysis of Distributed Control System of Nuclear Power Plant

2011 ◽  
Vol 383-390 ◽  
pp. 4281-4285
Author(s):  
Hu Wang ◽  
Shao Hua Li ◽  
Guang Cai Qi ◽  
Fu Sheng Lai
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Distributed Control ◽  
Preliminary Analysis ◽  
Nuclear Power ◽  
Power Plants ◽  
Continuous Operation ◽  
Distributed Control System ◽  
Control Methods ◽  
Reliability Parameters

The reliability of the nuclear power plant DCS is analyzed using Markov process to establish a mathematical model. And the initial use of the model on the three indicators of reliability parameters of nuclear power plants is calculated. The results showed that the model is correct,reliable and error rate is 9×10-10.DCS applies to preliminary analysis of the reliability of nuclear power DCS. Nuclear power plant DCS reliability is high enough, the minimum time of continuous operation is up to 66667 h, compared to conventional control methods more safe and reliable.

Design of an Ethernet Bus Interface Controller in a Nuclear Power Plant Simulator

2010 ◽  
Author(s):  
Lixuan Lu ◽  
Dong Le
Keyword(s):  
Control System ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Communication Networks ◽  
Nuclear Power ◽  
Power Plants ◽  
Distributed Control System ◽  
Training Requirements ◽  
The Many ◽  
And Training

Obsolescence presents great challenge to Nuclear Power Plants (NPP) and plant simulators around the world. Old designs will have to be either modified, or replaced by new designs, in order to simplify maintenance, increase availability and meet ever-increasing operational and training requirements. Control system upgrade and Distributed Control System (DCS) design for both old plants and new builds have become the center of interest. In a DCS, communication networks connect control systems together to allow the exchange of information and feedback. Among the many communication network protocols, Ethernet can be a promising one. This paper describes a new Ethernet Bus Interface Controller (eBIC) used in the Input/Output (I/O) system of a Nuclear Power Plant (NPP) simulator in Canada.

Recirculation Pump Speed Control System Upgrades in Nuclear Boiling Water Reactors

2008 ◽  
Author(s):  
James W. Morgan
Keyword(s):  
Control System ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Flow Control ◽  
Nuclear Power ◽  
Boiling Water ◽  
Boiling Water Reactors ◽  
Pump Speed ◽  
Water Reactors ◽  
Generator Sets

The nuclear power industry is faced with determining what to do with equipment and instrumentation reaching obsolescence and selecting the appropriate approach for upgrading the affected equipment. One of the systems in a nuclear power plant that has been a source of poor reliability in terms of replacement parts and control performance is the reactor recirculation pump speed/ flow control system for boiling water reactors (BWR). All of the operating BWR-3 and BWR-4’s use motor-generator sets, with a fluid coupled speed changer, to control the speed of the recirculation water pumps over the entire speed range of the pumps. These systems historically have had high maintenance costs, relative low efficiency, and relatively inaccurate speed control creating unwanted unit de-rates. BWR-5 and BWR-6 recirculation flow control schemes, which use flow control valves in conjunction with two-speed pumps, are also subject to upgrades for improved performance and reliability. These systems can be improved by installing solid-state adjustable speed drives (ASD), also known as variable frequency drives (VFD), in place of the motor-generator sets and the flow control valves. Several system configurations and ASD designs have been considered for optimal reliability and return on investment. This paper will discuss a highly reliable system and ASD design that is being developed for nuclear power plant reactor recirculation water pump controls. Design considerations discussed include ASD topology, controls architecture, accident, transient and hydraulic analyses, potential reactor internals modifications, installation, demolition and economic benefits.

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