consejo de seguridad nuclear psa applications program · consejo de seguridad nuclear psa...

IAEA Training Course on Safety Assessment of NPPs to Assist Decision Making

Consejo de Seguridad NuclearConsejo de Seguridad NuclearPSA Applications ProgramPSA Applications Program

Workshop InformationWorkshop InformationIAEA WorkshopIAEA Workshop City , Country

XX - XX Month, YearCity , Country

XX - XX Month, Year

LecturerLesson IV 3_11.9

LecturerLesson IV 3_11.9

IAEA Training Course on Safety Assessment of NPPs to Assist Decision Making 2

BackgroundBackground

– Historical perspective on regulations

• Defined set of accidents

• Focus on “safety” systems and prevention of core damage

• Traditional engineering concept to achieve high reliability (i.e single failure criteria, defense in depth, conservatism)

– Regulation that did not consider the entire plant or focusedon items less important than others non regulated

– Liberalized markets and competition require that regulation is focused on safety important issues


BackgroundBackground

– All operating plants licensed on deterministic engineering criteria

– Since late seventies, PSAs confirmed existence of high risk sequences not controlled by deterministic rules

– Deterministic rules address certain safety non-relevant items

– “Risk based regulation” buzzword in early nineties ( i.e. replacing deterministic regulation with risk insights)

– “Risk informed regulation” combines risk insights with prudent engineering requirements


Risk informed Risk informed regulation.regulation. WhatWhat is it?is it?

An approach to regulation where risk insights are considered together with other factors to establish requirements that focus licensee and regulatory attention on design and operational issues appropriate with their importance to “public health and safety”.

In RIR the regulatory decisions are NOT EXCLUSIVELY risk based (i.e. solely on calculated risk values)


Risk informed regulationRisk informed regulationPreconditionsPreconditions– PSA being of sufficient quality

• Methods and approaches used, coverage of PSA, data• PSA addressing all issues, uncertainties limited and understood • PSA documentation, independent reviews, regulatory approval(?)• Continuous (periodic) updating, reflection of operating

experience– Organizational conditions

• Regulatory framework allow for RIR• Availability of resources (i.e. tools, procedures and guidance)• Understanding of processes and adequate training

– Institutional issues• Dual regulatory “approach”• Decision making process with consideration of uncertainty


Risk informed regulationRisk informed regulationExpected benefitsExpected benefits

– Focusing regulatory attention on:• Safety relevant issues, on plants with performance problems• Increased effectiveness and pragmatism of the approach

– Optimized decision making• Safety significance intrinsic to decision taken• (More) transparent basis for decisions (rules established)

– Enhanced regulatory credibility and public confidence– Increased attention of licensees on safety issues– Reduce regulatory burden, thus increase competitiveness


PSA applications at CSNPSA applications at CSNBBBackgroundBackground

– Spanish PSA programme initiated in mid-eighties– All plants completed their plant specific PSA studies

• Level 1• Level 2• Internal and external hazards• Other operating modes (on going)

– CSN performing comprehensive reviews of all PSAs– PSAs of generally very high quality, regular updates– Risk Spectrum models available at CSN


PSA applications at CSNPSA applications at CSNBackgroundBackground

– Use of PSA to support specific regulatory decision at CSN since many years

– CSN’s own program on PSA based event analysis– CSN regulatory approach and rules well suited for PSA

applications– Commission's decision to introduce risk informed

approaches– Two-year PSA application project initiated in 2000– Aim to establish the infrastructure and introduce pilot

applications


CSN PSA applications projectCSN PSA applications project– Project goals and objectives

• To enhance utilization of PSA within CSN• To establish tools needed to support CSN PSA

applicationsTo develop a system containing PSA informationTo provide training seminar(s) on PSA applications for CSN staff

• To support development and adoption of methodologies for internal application of PSA

• To implement two different internal applications• Project started in summer 2000 to continue until 2002


CSN PSA applications projectCSN PSA applications projectAActivitiesctivities

– Selection of PSA applications• Collection of international experience on PSA

applications• Evaluation of applications with consideration of CSN’s

functions• Investigation of conditions for specific applications

within CSN• Interviews with regulators and research community

worldwide (personal and documents)• Workshop identified a total of 24 applications • Detailed assessment for 4 candidate applications


CSN functions vs. PSA applicationsCSN functions vs. PSA applications

YesYesYesYesPrioritization of regulatory Prioritization of regulatory research needsresearch needs

11ÑÑ) To establish and follow) To establish and follow--up research plansup research plans

------LL) To maintain relations with other similar LL) To maintain relations with other similar foreign organizationsforeign organizations

------L) To advise judicial and other public L) To advise judicial and other public administrations organizations, in NS/RPadministrations organizations, in NS/RP

YesYesYesYesPSA support to selection of PSA support to selection of scenarioscenario

11J) To issue and renew licenses for NPP operators J) To issue and renew licenses for NPP operators

------G) Control of radiation exposure of workers, the G) Control of radiation exposure of workers, the public and the environment.public and the environment.

YesYesNoNoPSA for predicting source PSA for predicting source term on plant statusterm on plant status

33F) Collaborate on emergency preparedness. F) Collaborate on emergency preparedness.

YesYesPartiallyPartiallyAssessment of risk Assessment of risk significance of deviationssignificance of deviations

--E) Propose enforcement activities and fines. E) Propose enforcement activities and fines.

YesYesYesYesRisk based inspectionRisk based inspection33C, D) Perform inspection activities, to assure C, D) Perform inspection activities, to assure compliance with rules and conditions compliance with rules and conditions established.[INSPECTION FUNCTION]established.[INSPECTION FUNCTION]

YesYesYesYesRisk based safety indicatorsRisk based safety indicators1414B) Issue binding reports to the Ministry of B) Issue binding reports to the Ministry of Economy before the license Economy before the license issuance.[ASSESSMENT FUNCTION]issuance.[ASSESSMENT FUNCTION]

yesyesYesYesRisk informed regulatory Risk informed regulatory rulesrules

33A) Propose to the Government regulations needed.A) Propose to the Government regulations needed.

Training and PSA summariesTraining and PSA summariesPSA info systemPSA info systemRepresentative ApplRepresentative Appl# of Appl# of ApplMAIN FUNCTIONMAIN FUNCTION


PSA applications projectPSA applications projectTasksTasks– PSA information system

• System developed placed on CSN network• ACSO PSA entered onto the system• System tested by about 25 individuals throughout CSN• Comments analyzed, test report, improvement plan

prepared– Risk based Inspection

• RII implementation plan for CSN prepared• CSN inspection practice evaluated • Tools and procedures developed: RII & SDPs• Pilot inspection with USNRC participation planned

– Seminar on PSA for CSN executives implemented in July 2001


CSN PSA application project CSN PSA application project PSA Information systemPSA Information system

– PSA of limited use to non PSA-specialists– PSA available as a hard copy/electronic

documentation, models – Non-specialists overwhelmed with extent of

documentation– PSA assumptions not always transparent– Limits in ability to use PSA insights to support

decision making– Risk informed applications require an easy use of

PSA information


CSN PSA application project CSN PSA application project Seminar(s)Seminar(s)

– Enhanced understanding of PSA and applications• To be provided on different topics and different levels• Seminars to be focused on applications, some basic PSA

technology• Experience of other regulators collected

USNRC seminars and courses evaluated for contents and impactEuropean regulators interviewed

•• Selection of topics:Selection of topics:Management seminar on PSA applications and support tools availableRBI seminar with USNRC site inspectors (after RBI tools in place)PSA information system seminar for wide usersPSA application seminar (second pilot application)


CSN PSA applicationsCSN PSA applications projectprojectRisk based inspectionRisk based inspection– Objectives of risk informed inspection process

Focusing inspection where potential risk is highApplying greater regulatory attention to plants with performance problem, less attention to good performersDefining understandable risk informed criteria to evaluate findings of inspections and other observationsNon-compliances addressed to reflect actual/potential safety impact

– Benefits from risk informed inspection• Systematic and transparent approach• Optimising resources and manpower• Increasing credibility of regulations


CSN PSA applicationCSN PSA application projectproject

– Future applications• Risk support to decision making

Exemptions to Tech SpecAssessment of significance of issues identified

• Risk based prioritization of regulatory research • Risk follow up

– Preparedness to response to utility applications• PSA-justified modification requests• Relaxation of Technical Specifications• Maintenance Rule

consejo de seguridad nuclear psa applications program · consejo de seguridad nuclear psa...

Documents