ML23150A030
| ML23150A030 | |
| Person / Time | |
|---|---|
| Issue date: | 05/17/2023 |
| From: | Kenneth Hamburger, Reinaldo Rodriguez NRC/NRR/DRA |
| To: | |
| Hamburger K | |
| Shared Package | |
| ML23150A023 | List: |
| References | |
| Download: ML23150A030 (9) | |
Text
Public Meeting on Risk Insights Associated with HEAF 1
Reinaldo Rodriguez Reliability and Risk Analyst Division of Risk Assessment Office of Nuclear Reactor Regulation US NRC LIC-504 Assessment
2 Background - Integrated Decision-Making Process for Emergent Issues (LIC-504)
- Developed as a lessons learned from Davis-Besse reactor vessel head degradation
- Provides a structured process and expectations to document decisions for issues that may warrant safety orders
- Provides guidance to apply integrated decisionmaking including risk, defense-in-depth, and safety margins considerations
- Has been used frequently for a range of emergent plant-specific and generic issues
- Not a substitute for other NRC processes Public Meeting on Risk Insights Associated with HEAF
3 LIC-504 Graded Recommendations - Examples Weigh a Spectrum of Regulatory Options Immediate regulatory action - compensatory measures Formal backfit analysis ( 10-4) 50.54(f) letters Bulletin Information Notice/Outreach Smart inspection samples -
within baseline program No Actions Use RIDM -
Not numbers alone 10-6 10-3 10-5 10-4 Change in CDF Regulatory Intensity 10-7 Public Meeting on Risk Insights Associated with HEAF
HEAF LIC-504 STEP 1 - NO IMMEDIATE SAFETY CONCERN STEP 2 - DETAILED EVALUATION USING DRAFT METHODOLOGY Public Meeting on Risk Insights Associated with HEAF 4
Scope Copper and aluminum HEAF zones of influence should be treated the same based on the current state of knowledge.
The LIC-504 assessment was then focused on examining the change in estimated HEAF risks associated with the use of the new HEAF PRA methodology.
Public Meeting on Risk Insights Associated with HEAF 5
Work Completed Visited one BWR and one PWR plant Assistance provided by each reference plant licensee was essential and added credibility and realism to the team's analyses The team generated risk-informed insights and recommendations Publicly available memo with WG recommendations was issued on July 22, 2022 (ADAMS Accession No. ML22201A000).
Public Meeting on Risk Insights Associated with HEAF 6
Staff Insights Public Meeting on Risk Insights Associated with HEAF 7
THE RISK OF HEAF COULD BE HIGHER OR LOWER THAN CALCULATED UNDER THE PREVIOUS METHODOLOGY RISK COULD VARY SIGNIFICANTLY BASED ON PLANT CONFIGURATION FOR CERTAIN CONFIGURATIONS, THE ESTIMATED RISK FROM NON-ISO-PHASE BUS DUCTS COULD BE NOTABLY HIGHER THAN PREVIOUSLY MODELED CONCLUDED THERE IS NO SIGNIFICANT INCREASE IN TOTAL HEAF RISK, THAT WARRANTED THE NEED FOR ANY ADDITIONAL REGULATORY REQUIREMENTS
Recommendations Public Meeting on Risk Insights Associated with HEAF 8
Information Notice Issue Risk insights into NRRs ongoing PRA configuration control initiative.
Incorporate Integrating risk insights into NRRs inspection program in accordance with ROPs change control processes.
Consider Risk insights with internal and external stakeholders.
Communicate
Q&As and Comments Public Meeting on Risk Insights Associated with HEAF