ML20351A411
| ML20351A411 | |
| Person / Time | |
|---|---|
| Issue date: | 12/16/2020 |
| From: | John Hughey NRC/NRR/DRA/APOB |
| To: | |
| John Hughey | |
| References | |
| Download: ML20351A411 (37) | |
Text
10 CFR 50.69 Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactors.
(General Overview)
Office of Nuclear Reactor Regulation Division of Risk Assessment PRA Oversight Branch
TOPICS 10 CFR 50.69 Rule 10 CFR 50.69 Approval Amendment 10 CFR 50.69 Implementation/Baseline Inspections 2
10 CFR 50.69 RULE Risk-Informed Safety Class 3
10 CFR 50.69 RULE Special Treatment Requirements Regulations specific Special requirements Treatment QA Requirements Requirements Inspection Testing Condition Monitoring Other Elements 4
10 CFR 50.69 RULE Special Treatment Requirements Retain Specific Special Special Treatment Treatment Requirements Requirements For RISC-1 For RISC-3 and RISC-2 and RISC-4 5
10 CFR 50.69 RULE Alternative Requirements Alternative List of Treatment Regulations in Requirements 50.69(b)(1)
For RISC-3 and RISC-4 6
10 CFR 50.69 RULE RISC-3 Alternative Treatments Reasonable Confidence:
- 1. Inspection/Testing:
Remain Capable of Performing Safety Related Function
- 2. Corrective Action:
Cause Identified and Action Taken to Prevent Repetition 7
10 CFR 50.69 RULE RISC-3 Alternative Treatments Reasonable Confidence VS Reasonable Assurance 8
10 CFR 50.69 RULE RISC-3 Alternative Treatments Criteria for Special Treatments in Reasonable Assurance The Regulations Combination of:
Criteria for Commercial Requirements Reasonable Confidence Engineering Specs Processes/Procedures QA Programs NUREG/CR-6752: ML020330051 9
10 CFR 50.69 RULE Categorization Process Categorize SSCs as RISC-1, -2, -3 or -4
- 1. Consider Plant-Specific PRA
- 2. Determine Functional Importance
- 3. Maintain Defense-in-Depth
- 4. Maintain Safety Margin/ Small Risk Increase
- 5. Categorize Entire Systems NEI 00 ML052900163 10 RG 1.201 - ML061090627
10 CFR 50.69 RULE Categorization Process Integrated Decision-Making Panel Experts/Plant-Knowledgeable PRA Safety Analysis Plant Operation Design Engineering System Engineering Rule Voluntarily Adopted by LAR Approval Approves Process/Program 11
10 CFR 50.69 RULE Feedback and Process Adjustment Review Plant Changes/IOE Timely (significant change)
At least every 2 refueling outages Adjustments to Ensure Categorization Process Remains Valid 12
10 CFR 50.69 RULE Program Documentation Basis for Removing Special Treatment Requirement UFSAR Update Quality Assurance Plan Update 13
10 CFR 50.69 RULE Reporting Requirements New RISC-1/-2 Reporting Requirements under 50.73 for Beyond Design Basis Events Reporting Under 10 CFR Part 21, 50.55(e), and 50.72, 50.73 For RISC-1 SSCs (existing requirements)
Reporting Under 50.72 and 50.73 For RISC-2 SSCs (existing requirements)
RISC-3 and RISC-4 SSCs Excluded From Reporting Requirements 14
10 CFR 50.69 LICENSE AMENDMENT Safety Evaluation Findings The 50.69 NRC Safety Evaluation Will Contain Numerous Findings/Conclusions of Reasonable Assurance of Safety 15
10 CFR 50.69 LICENSE AMENDMENT Safety Evaluation Findings Typical Findings/Conclusions:
Internal Events/Fire PRAs of Sufficient Quality/Level of Detail SSC Functional Importance Determined Using Appropriate Considerations Maintains Defense-In-Depth 16
10 CFR 50.69 LICENSE AMENDMENT Safety Evaluation Findings Typical Findings/Conclusions: (continued)
Reasonable Confidence RISC-3 SSCs Maintain Safety Margins/Increase in Risk Low Categorization of Entire Systems/Structures Categorization by IDP Made Up of Appropriate Individuals 17
10 CFR 50.69 LICENSE AMENDMENT Categorization Process Typical NRC Review and
Conclusion:
The NRC staff has evaluated the categorization steps and finds that the licensees process is consistent with all aspects of the process in NEI 00-04, as endorsed by RG 1.201.
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Limerick Example:
Submittal Dated Jan 19, 2018 , Fig. 5-1 ADAMS No. ML18019A091 19
10 CFR 50.69 LICENSE AMENDMENT PRA and Non-PRA Methods Typical Approved Methods in SE Internal Events (including internal flooding) PRA Fire PRA Seismic Margin Analysis 20
10 CFR 50.69 LICENSE AMENDMENT PRA and Non-PRA Methods Typical Approved Methods in SE: (continued)
External Hazards Screening Using IPEEE Shutdown Safety Assessment ANO-2 Passive Categorization Method for Class 2 and Class 3 SSCs 21
10 CFR 50.69 LICENSE AMENDMENT PRA and Non-PRA Methods Typical NRC Review and
Conclusion:
The NRC staff reviewed the PRA and the non-PRA methods used by the licensee in its 10 CFR 50.69 categorization process to assess the safety-significance of active and passive components and finds these methods acceptable and consistent with RG 1.201 and the NRG-endorsed guidance in NEI 00-04.
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10 CFR 50.69 LICENSE AMENDMENT Amendment License Condition The issued amendment revises the Facility Operating License to add a License Condition that typically specifies:
Approval to implement 50.69 PRA/other categorization methods Prior NRC approval for changes to categorization process Any specific implementation items 23
10 CFR 50.69 INSPECTION PROCEDURES 24
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 vs Baseline Inspections Adoption/ IP-37060 Event Inspection RISC-3 ROP Baseline Performance- Inspections Based Elements 25
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection Program Focused IP-37060 Adoption/Event Not Ongoing Baseline 26
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection The inspection will focus on two questions:
- 1. Did the site follow the requirements outlined in the license amendment and associated license conditions?
- Changes used PRA insights
- Boundaries correct
- Changes were based upon as-built and maintained plant
- 2. Are alternative treatment requirements implemented?
- System testing and maintenance performed as scheduled?
- Are the changes being monitored to assess effectiveness?
- Do the alternative treatment requirements provide reasonable confidence RISC-3 SSCs will perform their safety-related functions?
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10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection Verification of Program Aspects:
- Verify the licensee has implemented the license amendment in accordance with the associated safety evaluation:
- License conditions were implemented
- Site procedures reflect approved categorization process
- Sensitivity studies ensured proper categorization of RISC-3 components 28
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection Verification of Program Aspects: (continued)
- Verify programs in place for RISC-3 components:
Inspection Corrective
& Testing Actions 29
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection Review of licensee programs and procedures:
Defense-in-Depth Categorization SSC Importance Process Integrated Decision-making panel Entire System Safety Margins Categorized 30
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection Review of licensee programs and procedures: (continued)
RISC-1 and Reporting RISC-2 Requirements Feedback and Treatment Process Adjustments Program Documentation 31
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection RISC-3 Inspection Items:
Inspection Testing Reasonable Part 50 Corrective Action Confidence Appendix A Degradation of Extent of Multiple RISC-3 Condition SSCs 32
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection Inspection Helps:
NEI 00 (ADAMS Accession No. ML052900163)
RG 1.201 - (ADAMS Accession No. ML052900163)
ASME OM Code, Part 49 NUREG/CR-6752 - (ADAMS Accession No. ML020330051) 33
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection Points to Emphasize:
RISC-3 Alternative Treatment Justifications Reasonable confidence to perform safety function May need to retain some code/inspection requirements Potential Additional Treatment for RISC-1 and RISC-2 Crediting functions beyond design function Example: credit for steam relief valves passing water Reportability Requirements Applies to safety functions 34
10 CFR 50.69 INSPECTION PROCEDURES Baseline Inspection Procedures Inspection/Testing Baseline Corrective Action Inspections (RISC-3)
Feedback/Process Adjustment 35
10 CFR 50.69 INSPECTION PROCEDURES Baseline Inspection Procedures IP 71111.12 Maintenance Effectiveness IP 71111.18 Plant Modifications IP 71111.22 Surveillance Testing IP 7153 Followup of Events and Notices of Enforcement Discretion 36
Get Help!
John Hughey Phone: 301-415-3204 Email: john.hughey@nrc.gov Be RiskSMART - Reactor Safety (SharePoint) https://usnrc.sharepoint.com/teams/BeriskSMART-ReactorSafety/
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