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 2
10 CFR 50.69 Rule 10 CFR 50.69 Approval Amendment 10 CFR 50.69 Implementation/Baseline Inspections
10 CFR 50.69 RULE Risk-Informed Safety Class 3
10 CFR 50.69 RULE Special Treatment Requirements 4
Special Treatment Requirements Regulations specific requirements QA Requirements Inspection Testing Condition Monitoring Other Elements
10 CFR 50.69 RULE Special Treatment Requirements 5
Specific Special Treatment Requirements For RISC-3 and RISC-4 Retain Special Treatment Requirements For RISC-1 and RISC-2
10 CFR 50.69 RULE Alternative Requirements 6
Alternative Treatment Requirements For RISC-3 and RISC-4 List of Regulations in 50.69(b)(1)
10 CFR 50.69 RULE RISC-3 Alternative Treatments 7
- 1. Inspection/Testing:
Remain Capable of Performing Safety Related Function
- 2. Corrective Action:
Cause Identified and Action Taken to Prevent Repetition Reasonable Confidence:
10 CFR 50.69 RULE RISC-3 Alternative Treatments 8
Reasonable Confidence Reasonable Assurance VS
10 CFR 50.69 RULE RISC-3 Alternative Treatments 9
Criteria for Reasonable Assurance Special Treatments in The Regulations Criteria for Reasonable Confidence NUREG/CR-6752: ML020330051 Combination of:
Commercial Requirements Engineering Specs Processes/Procedures QA Programs
10 CFR 50.69 RULE Categorization Process 10 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 RG 1.201 - ML061090627
10 CFR 50.69 RULE Categorization Process 11 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
10 CFR 50.69 RULE Feedback and Process Adjustment 12 Review Plant Changes/IOE Timely (significant change)
At least every 2 refueling outages Adjustments to Ensure Categorization Process Remains Valid
10 CFR 50.69 RULE Program Documentation 13 Basis for Removing Special Treatment Requirement UFSAR Update Quality Assurance Plan Update
10 CFR 50.69 RULE Reporting Requirements 14 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
10 CFR 50.69 LICENSE AMENDMENT Safety Evaluation Findings 15 The 50.69 NRC Safety Evaluation Will Contain Numerous Findings/Conclusions of Reasonable Assurance of Safety
10 CFR 50.69 LICENSE AMENDMENT Safety Evaluation Findings 16 Typical Findings/Conclusions:
Internal Events/Fire PRAs of Sufficient Quality/Level of Detail SSC Functional Importance Determined Using Appropriate Considerations Maintains Defense-In-Depth
10 CFR 50.69 LICENSE AMENDMENT Safety Evaluation Findings 17 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
10 CFR 50.69 LICENSE AMENDMENT Categorization Process 18 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.
19 Limerick Example:
Submittal Dated Jan 19, 2018, Fig. 5-1 ADAMS No. ML18019A091
10 CFR 50.69 LICENSE AMENDMENT PRA and Non-PRA Methods 20 Typical Approved Methods in SE Internal Events (including internal flooding) PRA Fire PRA Seismic Margin Analysis
10 CFR 50.69 LICENSE AMENDMENT PRA and Non-PRA Methods 21 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
10 CFR 50.69 LICENSE AMENDMENT PRA and Non-PRA Methods 22 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.
10 CFR 50.69 LICENSE AMENDMENT Amendment License Condition 23 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
24 10 CFR 50.69 INSPECTION PROCEDURES This Photo by Unknown Author is licensed under CC BY
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 vs Baseline Inspections 25 Adoption/
Event RISC-3 Performance-Based Elements IP-37060 Inspection ROP Baseline Inspections
10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection 26 Program Focused Adoption/Event Not Ongoing Baseline IP-37060
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?
27
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:
29 Corrective Actions Inspection
& Testing
30 10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection Review of licensee programs and procedures:
Categorization Process SSC Importance Entire System Categorized Safety Margins Defense-in-Depth Integrated Decision-making panel
31 10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection Review of licensee programs and procedures: (continued)
RISC-1 and RISC-2 Treatment Reporting Requirements Program Documentation Feedback and Process Adjustments
32 10 CFR 50.69 INSPECTION PROCEDURES IP-37060 Implementation Inspection RISC-3 Inspection Items:
Reasonable Confidence Inspection Testing Corrective Action Extent of Condition Part 50 Appendix A Degradation of Multiple RISC-3 SSCs
33 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)
34 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
10 CFR 50.69 INSPECTION PROCEDURES Baseline Inspection Procedures 35 Inspection/Testing Corrective Action Feedback/Process Adjustment Baseline Inspections (RISC-3)
10 CFR 50.69 INSPECTION PROCEDURES Baseline Inspection Procedures 36 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
Get Help!
37 John Hughey Phone: 301-415-3204 Email: john.hughey@nrc.gov Be RiskSMART - Reactor Safety (SharePoint) https://usnrc.sharepoint.com/teams/BeriskSMART-ReactorSafety/