ML21161A350
| ML21161A350 | |
| Person / Time | |
|---|---|
| Issue date: | 05/05/2021 |
| From: | Charles Moulton NRC/NRR/DRA |
| To: | |
| References | |
| Download: ML21161A350 (30) | |
Text
Fire Protection Regulatory Guides and NFPA 805 Overview Briefing to the Advisory Committee on Reactor Safeguards May 5, 2021 Charles Moulton Fire Protection Engineer PRA Licensing Branch B Division of Risk Assessment Office of Nuclear Reactor Regulation
Outline
- Fire Protection Regulatory Guide Revisions
- Revision 4 to 1.189 Fire Protection for Nuclear Power Plants
- Revision 2 to 1.205 Risk-Informed, Performance-Based Fire Protection for Existing Light-Water Nuclear Power Plants
- Overview of Risk-Informed, Performance-Based Fire Protection Program [10 CFR 50.48(c)]
- Specific Technical Topics for Implementation of 10 CFR 50.48(c)
- Summary
Changes in RG 1.189, Revision 4 Purpose of revision was to include updated guidance
- Incorporates guidance on fire-induced circuit failures
- Endorses portions of Nuclear Energy Institute (NEI) 00-01, Guidance for Post Fire Safe Shutdown Circuit Analysis, Revision 4
- NUREG/CR-7150, Joint Assessment of Cable Damage and Quantification of Effects from Fire (JACQUE-FIRE), Volumes 1, 2, and 3
- Organizational changes to align with current regulatory guide format
Changes resulting from public comments
- 25 public comments received
- Expanded discussion of circuit analysis details from NUREG/CR-7150, Volume 3 and NEI 00-01
- Various clarity edits
Unincorporated comments
- Revise definition of not adversely affect safe shutdown to remove discussion of sufficient safety margins
- Current text included since RG 1.189, Revision 1, published in 2007
- Has not prevented successful use of RG 1.189 by the industry and the staff
- Expand guidance to include passively safe advanced reactor designs
- Beyond the scope of the current revision
- Part 53 is under development and will have separate guidance
Changes in RG 1.205, Revision 2 Purpose of revision was to include updated guidance
- Endorses NEI 04-02, Guidance for Implementing a Risk-Informed, Performance-Based Fire Protection Program Under 10 CFR 50.48(c), Revision 3
- Incorporation of remaining NFPA 805 Frequently Asked Questions
- Latest guidance on fire-induced circuit failures
- Endorses portions of NEI 00-01, Guidance for Post Fire Safe Shutdown Circuit Analysis, Revision 4
- NUREG/CR-7150, Joint Assessment of Cable Damage and Quantification of Effects from Fire (JACQUE-FIRE), Volumes 1, 2, and 3
Changes from public comments
- 6 public comments received
- Expanded discussion of NFPA 805 Section 1.7 equivalency for closer alignment with issued license condition text
Features of a Fire Protection Program Under 50.48(c)
10 CFR 50.48(c) background
- Endorses NFPA 805
- Rule issued June 16, 2004
- Incorporates by reference the 2001 Edition of NFPA 805 with exceptions, clarifications, and supplementations
- Risk-informed, performance-based fire protection program is a voluntary alternative to the existing prescriptive, deterministic fire protection regulations (i.e., Appendix R)
NFPA 805 Features
- Requirements are applied during all phases of plant operation
- Establishes fundamental fire protection program elements and design requirements for fire protection systems and features
- Allows the nuclear safety performance criteria to be satisfied deterministically or using a performance-based approach
- Implementation of the performance-based approach includes an integrated assessment of risk, defense-in-depth, and safety margin
- NFPA 805 allows licensees to self approve certain changes to their fire protection program using performance-based methods
Differences from Appendix R NFPA 805
- All phases of operation
- Achieve & maintain fuel in safe and stable condition
- One success path free from fire damage Appendix R
- Power operation
- Hot shutdown and cold shutdown requirements
- One train free from fire damage
Differences from Appendix R (continued)
- No deterministic emergency lighting requirements
- Feasible recovery actions allowed for compliance in performance-based approach
- Radiological release criteria are explicit Appendix R
- Deterministic requirements for emergency lighting
- Operator manual actions cannot be used to demonstrate compliance with III.G.2
- Radiological release criteria are implicit
NFPA 805 License Condition Major Elements
Self-approval of program changes
- Risk-informed changes to FPP without prior NRC approval
- Risk assessment of the change shows acceptance criteria are met:
- risk decrease, or
- Acceptance criteria were developed starting from RG 1.174 guidelines
- Consistent with defense-in-depth and maintains sufficient safety margins
- Risk assessment approach, methods, and data shall be acceptable to the NRC
- methods used in the peer-reviewed fire PRA model
- methods that have been approved by NRC for use in NFPA 805 applications
- methods that have been demonstrated to bound the risk impact
Self-approval of program changes (continued)
- Other changes that may be made without prior approval
- Changes that Have No More than Minimal Risk Impact
- Changes to Chapter 3 fundamental requirements
- Functionally equivalent to the corresponding technical requirement
- Adequate for the hazard; only applies to 4 sections of Chapter 3:
- Fire Alarm and Detection Systems (Section 3.8);
- Automatic and Manual Water-Based Fire Suppression Systems (Section 3.9);
- Gaseous Fire Suppression Systems (Section 3.10); and,
- Passive Fire Protection Features (Section 3.11).
Transition license condition
- Cannot self-approve risk-informed changes unless there is no more than a minimal risk impact
- Modifications and programmatic implementation items
- Necessary for full compliance
- Committed schedule for completion
- Maintain appropriate compensatory measures in place until completion of the modifications
Specific Technical Topics for Implementation of 10 CFR 50.48(c)
Success Path
What is a success path?
- A comprehensive list of systems and equipment and their interrelationships
- The components required to achieve the nuclear safety performance criteria
- Components required to achieve and maintain the nuclear safety functions and components whose fire-induced failure could prevent the operation or result in the maloperation of those components needed to meet the nuclear safety performance criteria
Success path approach
- Identify plant systems required to achieve each of the nuclear safety criteria
- Also consider the essential mechanical/environmental support and essential electrical systems
- Equipment identification
- Identify equipment required to achieve the nuclear safety objectives
- Identify equipment whose spurious operation could prevent achieving the nuclear safety objectives
- Performance-based
- All system and equipment identification includes related cables
Recovery Actions Formerly Operator Manual Actions
Recovery Actions in NFPA 805 Activity to Achieve the Nuclear Safety Performance Criteria?
No Yes Action taken in the Main Control Room?
Action taken at the Primary Control Station?
RA to Demonstrate Availability of a Success Path?
Add RA to Fire Protection Program Activity Is a Recovery Action (RA)
Activity is Not a Recovery Action (RA)
Evaluate & Report Additional Risk Per §4.2.4 No No No Yes Yes Yes Done For each Fire Area
Primary control station
Performance-Based Analysis
Performance-based approach overview
- If a fire area has a variance from the deterministic separation requirements, the licensee may
- Modify the plant
- Use fire risk evaluation approach
- Use fire modeling approach (shows risk is negligible)
- If a success path recovery action is involved, the additional risk (compared to deterministic compliance) must be assessed
- May use fire modeling or fire risk evaluation approaches
- May be qualitative or quantitative; bounding is allowed
Plant Change Evaluations
- Risk-informed evaluation of a change to a previously approved fire protection program element:
- integrated assessment of risk, defense-in-depth, and safety margins
- Ensures public risk from fire-induced nuclear fuel damage accidents is low and that adequate defense-in-depth and safety margins are maintained
- Similar to Fire Risk Evaluation performance-based approach
Summary
- Revisions to RG 1.189 and 1.205 reflect latest guidance
- No substantial objections or alignment issues from public comments
- NFPA 805 provides the framework for a risk-informed, performance-based fire protection program
- AHJ - Authority Having Jurisdiction
- CDF - Core Damage Frequency
- CFR - Code of Federal Regulations
- FAQ - Frequently Asked Question
- GDC - General Design Criteria
- IEEE - Institute of Electrical and Electronics Engineers
Acronyms (continued)
- JACQUE-FIRE - Joint Assessment of Cable Damage and Quantification of Effects from Fire
- MCR - Main Control Room
- NEI - Nuclear Energy Institute
- NFPA - National Fire Protection Association
- NRC - Nuclear Regulatory Commission
Acronyms (continued)
- PSA - Probabilistic Safety Assessment
- PWR - Pressurized Water Reactor
- RA - Recovery Action
- RG - Regulatory Guide