Risk Monitoring for Nuclear Power Plant Applications Using Probabilistic Risk Assessment

Abstract

Systematic and comprehensive Probabilistic Risk Assessment (PRA) is used to evaluate risks for Nuclear Power Plants (NPPs), and the risk information is also used to enhance the rationality and accountability of safety-related activities, and to realize efficient management in NPPs. Regulators and industry are discussing the standards and guidelines for the various types of PRA and management for near-future usage. “Risk Monitoring” is the essential item for PRA usage and risk-informed activities, and we assume “At-power risk monitoring in case of On-Line Maintenance” and “Shutdown risk evaluation for every outage” are two key issues for “Risk Monitoring.” This chapter describes the COSMOS Risk Monitoring system, and also of its usage for “At-power risk monitoring in case of On-Line Maintenance” and “Shutdown risk evaluation for every outage.”

Nomenclatures

BDD:

Binary decision diagram

CDF:

Core damage frequency

DID:

Defense-in-depth

ET:

Event tree

FT:

Fault trees

GUI:

Graphical user interface

IE:

Initiating event

NEL:

Nuclear engineering Ltd

NPP:

Nuclear power plants

OLM:

On-line maintenance

OOS:

Out-of-service

POS:

Plant operating state

PRA:

Probabilistic risk assessment

RCS:

Reactor coolant system

RHRS:

Residual heat removal system

SG:

Steam generator