ML20195A396
| ML20195A396 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 07/13/2020 |
| From: | Public Service Enterprise Group |
| To: | Office of Nuclear Reactor Regulation |
| Kim, James | |
| References | |
| Download: ML20195A396 (10) | |
Text
Salem Pressurizer Weld Interval Extension Request for Alternative July 20, 2020 PSEG/NRC Pre-Submittal Meeting
Agenda Overview of Request Affected Components Proposed Alternative Basis for Request Technical Justification Applicability & Inspection History Proposed Schedule 2
Overview of Relief Request PSEG will be requesting approval of a Request for Alternative in accordance with 10 CFR 50.55a(z)(1) to increase the inspection interval for pressurizer shell-to-head welds for Salem Units 1 & 2 Affected Components Pressurizer, ASME Class 1, Category B-B, Pressure-retaining welds in vessels other than reactor vessels 3
ASME Category Item No.
Description B-B B2.11 Pressurizer, shell-to-head welds, circumferential B-B B2.12 Pressurizer, shell-to-head welds, longitudinal
Proposed Alternative PSEG proposes to increase the inspection interval for the pressurizer shell-to-head welds from 10 to 30 years for the remainder of the fourth interval and through the fifth 10-year inspection interval (currently scheduled to end on December 31, 2030) 4
Basis for Request EPRI Report 3002015905, Technical Bases for Inspection Requirements for PWR Pressurizer Head, Shell-to-Head and Nozzle-to-Vessel Welds This report is applicable to ASME Categories B-B and B-D This report is publicly available for download at www.epri.com 5
Technical Justification
- The EPRI Report provides the following technical justifications that support PSEGs Request for Alternative:
Industry examination history and previous similar industry initiatives have optimized examination requirements for similar components
The report contains a Degradation Mechanism Evaluation specific to the welds included in PSEGs request
The report contains Probabilistic Fracture Mechanics (PFM) and Deterministic Fracture Mechanics evaluations specific to the welds included in PSEGs request The PFM evaluations are consistent with the PFM guidance EPRI provided to the NRC
The report provides results for the welds included in PSEGs request that conclude that no other inspections are required before 80 years of operation to satisfy the NRC safety goal of 10-6 failures per reactor year
The report demonstrates that the welds included in PSEGs request are very flaw-tolerant 6
Applicability and Inspection History
- PSEGs Request is limited to ASME Category B-B welds These welds represent the upper and lower head circumferential and longitudinal shell welds; no nozzle welds are included in the Request because the nozzles are integrally cast
- PSEGs Request will demonstrate that plant specific configurations and operating conditions are bounded by the criteria used in the EPRI report
- PSEGs Request will supplement the EPRI report with Salem-specific evaluation for weld coverage because prior inspections at Salem had less coverage than the minimum coverage assumed in the EPRI report (as low as 37% for some welds at Salem vs. 50% assumed in the EPRI report)
Leakage criteria satisfied for 77 years of operation and rupture criteria below acceptance criteria for 80 years of operation 7
Applicability and Inspection History
- PSEGs Request includes a summary of the Salem inspection history for the subject welds No flaws were detected in any of the prior examinations for these welds that exceeded the ASME Section XI acceptance standards
- Conclusion of PSEGs Request: ASME Section XI inspection schedules can be optimized (to at least 30 years) without compromising safety 8
Proposed Schedule PSEG currently intends to submit the Request for Alternative before the end of August 2020 PSEG will request NRC approval no later than August 31, 2021 to support implementation prior to the Fall 2021 outage for Salem Unit 2 9
Questions?
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