ML25016A264
| ML25016A264 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 10/15/2024 |
| From: | Entergy Corp |
| To: | Ali Rezai NRC/NRR/DNRL/NPHP |
| References | |
| Download: ML25016A264 (1) | |
Text
Power Outage NRC Brief on ANO-2 2R30 Nozzle 71 Half Nozzle Repair October 15, 2024
2 Agenda 1.Problem Statement 2.Proposed Solution 3.Project Schedule 4.Comments / Questions
3 Problem Statement During performance of the RVCH inspection in accordance with Code Case N-729-6 and Relief Request ANO2-ISI-022, an indication was found on Control Element Drive Mechanism (CEDM) Penetration 71.
A manual surface examination using Liquid Penetrant (PT) was performed in an attempt to establish surface connectivity.
4 Nozzle 71 Location
- Outermost Row
- 49.6° angle of incidence
- No fabrication flaws or special interest indications previously noted on CEDM 71 at this location
5 Nozzle 71 Indication
- Bare metal visual on top of head -
No visible leakage
- Clean UT leak path assessment
- Clean Eddy Current from tube ID
6 Evaluation
- Rapid appearance and growth suggested PWSCC
- Fatigue crack considered but concluded to be unsupported
- Potential surface connection using PT
- Undetected growth of cracks thru welds supported by internal OE at Indian Point 2 in 2018 Decision made to proceed with half nozzle repair with Framatome
7 Half-Nozzle Repair No significant change in the repair process, except roto-peening will not be performed for this repair.
To address this, Entergy will provide:
a.
The highest weld residual plus operating stress through-wall profile of the nozzle adjacent to the weld and the rolled-expanded regions.
b.
The estimated crack growth rate for the roll-expanded region.
c.
The hydrogen concentration expected during the next cycle of operation.
8 Project Schedule Milestone Target Date Request Submitted 10/20/2024 Request Authorization 10/22/2024 Field Work Completed 10/22/2024 Return to Service 10/24/2024 One-Cycle Justification Analyses Within 14 Days After Startup Life of Repair Analyses Prior to 2R31 (2nd Quarter 2026)
9 Questions?