ML19011A438
| ML19011A438 | |
| Person / Time | |
|---|---|
| Issue date: | 01/16/2019 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| Nathan Siu 415-0744 | |
| Shared Package | |
| ML19011A416 | List:
|
| References | |
| Download: ML19011A438 (19) | |
Text
Risk-Informed Regulatory ApplicationsLecture 8-11 Key TopicsU.S. applications general and more examples*Regulations and guidanceLicensingOversightOperational experience2Overview*See also Lecture 1-2 ResourcesDecisionmakingNUREG-2201, U.S. Nuclear Regulatory Commission, September 2016.-Informed Regulation at the U.S. Nuclear -https://www.nrc.gov/about-nrc/regulatory/risk-informed/rpp.html3Overview Other References G. ApostolakisNUREG-2150, U.S Nuclear Regulatory Commission, April 2012.Century: The Near-Term Task Force Review of Insights from the Fukushima Dai-ichiAccident, July 12, 2011. (ADAMS ML111861807)NUREG-1489, March 1994.-Informed Regulation: The Role of NRC Commissioner Speech S-98-26, 26thAnnual Water Reactor Safety Meeting, October 26, 1998. (ADAMS ML003711267)P.K. Samanta-Based Analyses of NUREG/CR-6141, December 1994. Statement for License Renewal of Nuclear PlantsNUREG-1437, Revision 1, June 2013.4Overview Other References (cont.) Training Course P111: PRA Technology and Regulatory Perspectives, Module S, U.S. Nuclear Regulatory Commission. (ADAMS M12160A497)Inspection Manual Chapter 0410, October 4, 2012. (ADAMS ML12263A456)Inspection Manual Chapter 0609, June 2, 2011. (ADAMS ML101400479)-Informed Decision-Office of Nuclear Reactor Regulation Office Instruction LIC-504, Revision 4, June 2, 2014. (ADAMS ML14035A143)Management Directive 6.4, January 15, 2015. (ADAMS ML14245A048)NUREG-0933, Main Report with Supplements 134, latest version available from http://nureg.nrc.gov/sr0933/Introduction/Introductions.html, December 2011.5Overview All Functions, All Arenas6Risk-Informed Regulation Regulatory ApproachStandard*Principles**IndependenceOpennessEfficiencyClarityReliability7* When granting, suspending, revoking, or amending licenses or construction permits. (Atomic Energy Act of 1954, as amended see NUREG-0980, v1, n7, 2005)**NRC Strategic Plan (NUREG-1614, v6, 2014)Risk-Informed Regulation Risk-Informed RegulationRisk information used to strengthen requirements, relax requirements, provide flexibility in meeting requirements (as long as adequate protection is ensured).Numerous rules:Backfit10 CFR 52.47 (New Reactor Certification and Licensing)Guidance documents support each application. (See Lecture 8-2)8regulatory guide, or generic letter we issue, the Commission conducts a regulatory analysis to weigh the costs associated with the action against the risk reduction and safety enhancement to be S.A. Jackson (1998)Regulations and Guidance In the Future?Post-Fukushima Near-Term Task Force: recommended regulatory requirements and NUREG-2150 (initiated pre-Fukushima): proposal to increase use of risk information Concerns with resources, disruption during agency response9Regulations and Guidance Changes in Plant Licensing Basis (RG 1.174)Voluntary changes: licensee requests, NRC reviewsSmall risk increases might be acceptableChange requests may be combinedDecisions are risk-informed10Licensing Risk-Informed Technical SpecificationsAn early application of PRA technology [See Bickel (1983), Samantaet al. (1994)]11Unavailability (and risk) increases with AOT and with STI. Why might the proposed changes be acceptable?Currently allowed completion timeProposed completion timeCurrently allowed STIProposed STILicensing Plant License RenewalEnvironmental reviews consider potentially cost-beneficial severe accident mitigation alternatives (SAMA)Plant-specific PRAs not required but typically used to support evaluationsNRC reviews (supplements to NUREG-1437) often have information on risk contributors, sometimes have history of PRA model12Licensing Oversight ActivitiesReactor Oversight Program*InspectionsPerformance indicators (including Mitigating Systems Performance Index)Significance Determination Process SDP Incident Investigation (Management Directive 8.3)*Notice of Enforcement Discretion (NOED)13OversightCDF < 1E-6LERF < 1E-71E-6 < CDF < 1E-51E-7 < LERF < 1E-61E-5 < CDF < 1E-41E-6 < LERF < 1E-5CDF > 1E-4LERF > 1E-5CDF = Core damage frequencyLERF = Large early release frequency*See Lectures 1-2, 7-1 Operational ExperienceAccident Sequence Precursor (ASP) Program (Lecture 7-1)Emergent Issues (LIC-504)Generic Issues14Operational Experience Emergent Issues15LIC-504Operational Experience Generic Issues ProgramAddresses multi-facility issues affecting public health and safety, the common defense and security, or the environment (with respect to radiological health and safetyRequired by Congress; status and resolutions reported to Congress and the publicIssues can be raised by public or by staffThree stagesScreeningAssessment (including consideration of risk)Regulatory Office Implementation16Operational Experiencehttps://www.nrc.gov/about-nrc/regulatory/gen-issues/dashboard.html#genericIssue/genericIssueDetails/3 Decision SupportR&D and other technical support (see Lecture 8-2)Near-term regulatory applicationLonger-term anticipated needRisk-informed R&D prioritization: coming soon?17Decision Support Positive Outcomes from PRA*Actionable safety insights and lessonsImportance of SBO, auxiliary feedwater, human error, CCF, fires and external hazardsPlant-specific nature of riskChanges that improved plant responses to actual eventsImproved plant performanceImproved equipment reliability and plant performance under Maintenance RuleReduced outage durations increased capacity factorsReduced worker doses (risk-informed in-service inspections)Increased objectivity of regulatory oversight (ROP)18*Not all resulting from regulatory activities Thought ExercisesRisk-Informed Technical SpecificationsThe pre-outage unavailability growth curves look linear. Under what conditions is this reasonable?The computed risk increases from extending an AOT extensions be allowed?19