Font Size: a A A

Study On A Reliability Analysis Method For Digital Control System Of Nuclear Power Plant Based On Multilevel Flow Models

Posted on:2014-10-03Degree:MasterType:Thesis
Country:ChinaCandidate:W Q ChenFull Text:PDF
GTID:2252330425966056Subject:Nuclear science and engineering
Abstract/Summary:PDF Full Text Request
Because of the potential accident which may cause huge damage to the environment andpublic in nuclear power plant (NPP), the safety and reliability of the NPP has become ansignificantly important research issue in the development of nuclear energy. The digitalcontrol system (DCS), which is becoming more and more widely used in the NPP hassignificant operational and economic advantages over traditional analog control system.The DCS affect the safety of NPP deeply. Because there are presently no universallyaccepted methods for modeling digital systems in current probabilistic safety assessment(PSA) and the technical departments of PSA haven’t made an agreement, so the traditionalFault Tree/Event Tree approaches are still used in the PSA of NPP, but they couldn’t accountfor dynamic and multiple states behavior of DCS as these two methodologies have significantlimitations when model the DCS.On the basis of Multilevel Flow Models (MFM) theory for control system, this thesispresents a methodology for modeling the DCS of NPP and then studys its reliability. Thisthesis consists of the following parts:(1) First analyze the application of DCS in NPP and then summarize the influence ofDCS to NPP, the current reliability research work and the requirement for PSA of DCS.(2) This thesis presents an effective approach to model DCS of NPP which is based onmodified MFM and the model developed by this method could be studied for the purpose ofreliability assessment.(3) A qualitative and quantitative method to analyze the DCS is studied in detail basedon the modified MFMs.Study the method of mapping MFM to multistate fault trees (MFT)and the subsequent qualitative assessment of MFT. A BDD based method is used to conductits quantitative analysis which could be used to calculate the failure probability of unexpectedstates. A case study is given to show the practicality of proposed methodologies.(4) The NPP including DCS is modeled by MFM in detail and a reliability assessmentsystem for DCS of NPP is design primarily. The feedwater control system is model andanalyzed using the proposed method in this thesis.This thesis apply the modified MFM which could properly and effectively model the reliability of digital control system of NPP and provide a useful approach for the future PSAof DCS.
Keywords/Search Tags:Reliability assessment, Nuclear Power Plant, Digital control system, MultilevelFlow Models, probabilistic safety assessment
PDF Full Text Request
Related items