ML21231A167
| ML21231A167 | |
| Person / Time | |
|---|---|
| Issue date: | 08/18/2021 |
| From: | Mike Franovich Office of Nuclear Reactor Regulation |
| To: | |
| S Mehta | |
| References | |
| Download: ML21231A167 (21) | |
Text
Risk Management Committee Meeting PWROG Meeting: August 18, 2021 Michael X. Franovich, Director Division of Risk Assessment Office of Nuclear Reactor Regulation 1
AGENDA RIPE - Updates on Temporary Staff Guidance Updates to RG 1.201 Potential Endorsement of IEEE 1819-2016 2
Treatment of FLEX in PRAs and LARs
3 IDP PRA RIPE (using existing regulations)
Integrated Decision-making Panel (IDP) Reviews Key Engineering Principles Demonstrated Probabilistic Risk Assessment Acceptability RIPE Leverages Previous Risk-Informed Initiatives
4 Expansion of RIPE
- RIPE was originally only available to licensees who had a previously approved TSTF-505 license amendment.
- RIPE was expanded in Revision 1 to allow licensees to demonstrate they have a technically acceptable PRA using an approved TSTF-425 amendment.
- Expansion of RIPE was documented in a memo to the NRR Office Director dated June 30, 2021 (ML21180A012).
- Enclosure 1 - Guidelines for Characterizing the Safety Impact of Issues, Revision 1 (ML21180A014)
- Enclosure 2 - Temporary Staff Guidance TSG-DORL-2021-01, Revision 1 (ML21180A013)
50.69 IDP or Equivalent TSTF-425 &
50.69 IDP or Equivalent Future work - Other risk information Streamlined Review -
No review of PRA or deterministic review Risk-informed review
6 Whats Next for RIPE?
Finalized Expansion of RIPE to include licensees with an approved TSTF-425 license amendment (ADAMS Package ML21180A011)
Continue working on graded approach to support other levels of risk-informed integrated decision-making.
Continue outreach to other interested parties and the public.
7 Treatment of FLEX Credit in Risk-Informed LARs
- Initially, LARs provided limited information to support credit
- Staff has been issuing multi-part RAIs to address all contingencies including human error probabilities, failure rate/demand probability, PRA upgrade, impact on application
- May 30, 2017 NRC memo
- Variety of meetings with industry
8 Guidance on Key Assumptions and Sources of Uncertainty comparison of the PRA results with the acceptance guidelines must be based on an understanding of the PRA contributors to the PRA resultsand the impacts of the uncertainties, both those that are explicitly accounted for in the results and those that are not.
RG 1.174 NRC reviewer
[will] focus their review on key assumptions and areas identified by peer reviewer as being of concern [i.e.,
F&Os]
RG 1.200 Guidance on Treatment of Uncertainties Associated with PRAs NUREG 1855
9 Overarching statement on FLEX credit Permanently installed equipment Portable equipment Data sources and updates Human actions Revised NEI Guidance
10 Observations/Next Steps
- Recent adherence to NEI FLEX guidance has been mixed
- PWROG report on equipment reliability
- Revision to May 30, 2017 memo
11 Potential Endorsement of IEEE 1819-2016 "IEEE Standard for Risk-Informed Categorization and Treatment of Electrical and Electronic Equipment at Nuclear Power Generating Stations and Other Nuclear Facilities" December 26, 2019:
NRC states that staff will consider feasibility of endorsing IEEE 1819-2016.
October 15, 2019:
IEEE requests priority for endorsement of IEEE 1819-2016 based on increased NRC emphasis on risk-informed categorization.
2016: IEEE Develops IEEE 1819-2016 standard for risk categorization of EESCs as a complement to existing standards.
2004: IEEE develops a goal to incorporate risk-informed methods into IEEE standards for electrical and electronic systems and components (EESCs).
12 Potential Endorsement of IEEE 1819-2016 10 CFR 50.69 Reg Guide 1.201 NEI 00-04 -or-Other methods Where would IEEE 1819-2016 fit into the existing regulatory framework?
13 Similar Risk Categories to RG 1.201 and NEI 00-04 IEEE 1819-2016 RG 1.201 and NEI 00-04 Deterministic
14 Similar Inputs to NEI 00-04 Risk Characteriz-ation Deterministic Principles Risk Insights from Approved PRA Sensitivity Studies Periodic Reviews Treatments and Corrective
specific guidance Quantitative Method for some EESCs (Annex B)
15 Potential Endorsement of IEEE 1819-2016 Identify and develop system functions based on providing power to the served loads Maintain specific associations between EESCs and their power sources Considerations for specific components such as breakers, cables, or relays EESC-specific guidance Applies to system functions not associated with supplying power to SSCs; (e.g., fault protection, alarms, lighting), or to unanalyzed system functions For each system function, determine an overall risk by assigning numeric answers to essential risk questions One suggested method using a sliding scale of 1-4 is provided in Annex B; other methods may be developed New Quantitative Method for some EESCs (Annex B)
16 Endorsement Paths ENDORSED RG 1.201 update Endorse in full Endorse in Part Clarifications Sections not endorsed New RG Endorse in full Endorse in part Clarifications Sections not endorsed NOT ENDORSED
17 Potential Updates to RG 1.201 Mature Robust 50.69 Categorization Methodology Developed Over Many Years 2002 South Texas Project Proof of Concept November 2004 Promulgate 10 CFR 50.69 Rule July 2005 NEI 00-04 50.69 SSC Categorization Guideline May 2006 Regulatory Guide 1.201 Rev 1, For Trial Use December 2014 Vogtle Pilot approved 2017 Second LAR submittal August 2021 24 sites approved 5 LARs under review LARs based on RG 1.201 with changes
18 50.69 Categorization Process Evolved Beyond Current RG 1.201 Rev 1 Internal Events PRA Fire PRA Fire Induced Vulnerability Evaluation (FIVE)
Appendix R Safe Shutdown Equipment List (SSEL)
Seismic Seismic Margin Analysis SSEL PRA Alternate Tiered EPRI Approach Passive ANO-2 N-660 Limerick Proposed Alternate Shutdown Shutdown Safety Plan PRA Other External Hazards Hazard Screening PRA In RG 1.201 AND used in LARs In RG 1.201 NOT used in LARs Not yet in RG 1.201 Under Review
19 Alternative Tiered EPRI Seismic Approach
- A three-tiered for plants with low, medium and high seismic hazard/margin (EPRI Report 3002012988) proposed for plants without SPRA or SMA
- To support the approach, EPRI Report uses four seismic PRAs to identify insights related to seismic risk
- Claims that most seismic risk significant SSCs are already captured by the internal events and/or fire PRAs
- Identifies unique seismic insights and failure modes
- Tier 1 (low risk) approved for several plants
- Tier 2 (medium risk) approved for one plant
- No plants have submitted for Tier 3 19
20 Limerick Application under Review
- Changes proposed to the 50.69 categorization process
- Alternate defense-in-depth methodology as described in PWROG-2015-NP, Rev. 1 (ML21082A522) in lieu of the defense-in-depth methodology in Chapter 6 of NEI 00-04
- Alternate passive pressure boundary component categorization as described in EPRI 3002015999 (ML21082A171) in lieu of the approved ANO-2 methodology
- Early stages of review
21 Questions?