ML21307A105
| ML21307A105 | |
| Person / Time | |
|---|---|
| Issue date: | 11/30/2021 |
| From: | Laura Kozak, Antonios Zoulis NRC/NRR/DRA/APOB, Division Reactor Projects III |
| To: | |
| References | |
| Download: ML21307A105 (7) | |
Text
PRA Counterpart Meeting Antonios M. Zoulis, Branch Chief Laura Kozak, Senior Reactor Analyst PRA Oversight Branch, DRA, NRR November 2021
The NRC has a concern that licensees are not evaluating the OPC, and the Open Phase Isolation System (OPIS) for inclusion into their PRA models of record. This has been observed during the Open Phase TI inspections.
While the level of risk from OPC doesnt rise to the level of backfit, it can affect Risk Informed Decisionmaking activities. It also does not reflect the as-built as operated plant.
OPC can particularly affect plant risk during RICT or (a)(4) assessments when plant configurations change. For instance, by removing an offsite power transformer from service for a workweek configuration leaving the plant and its safety buses aligned to a single source of offsite power for the duration of the maintenance window.
Requirements Supporting Review 1-5.3 of the ANS PRA Standard discusses monitoring of PRA inputs and collecting new information for the PRA Configuration Control Program.
The OPC is industry-wide operational experience that affects the PRA. It resulted in plant modifications, procedure changes, and in some cases, operator actions.
This may change the results of the PRA and can affect RIDM in the future.
Requirement NFPA-805 SFCP RICT 50.69 a(4)
- As-built, as-
- License
- License
- License
- 10 CFR
- NUMARC operated condition condition Condition 50.69(e)(1) 93-01, Rev plant
- Standard
- ASME/ANS
- ASME/ANS
- ASME/ANS 4F, Section Section Ra-Sa-2009 Standard Ra-Sa-2009 11.3.3 2.4.3.3 Ra-Sa-2009 (a)(4)
NFPA-Reflect As- RICT 805 built As-Operated plant SFCP 50.69 4
Questions?
5
Back Up Slide Requirements Supporting Review Could affect PRA:
Monitor PRA inputs and - Design Input Changes - Operation collect new information
- Maintenance Maintains and - Industry-wide Upgrades the PRA operational history consistent with the as-ASME/ANS Ra-Sa- built, as operated 2009 Section 1-5 plant - Changes to inputs or Key Elements new information shall PRA Configuration Ensures cumulative Control (CC) be evaluated impact of pending - Relevant changes to a changes is considered specific application (i.e.,
RICT, SFCP, 50.69) shall Maintains CC of meet pertinent SRs for computer codes the application.
Documentation 7