ML21278B091
| ML21278B091 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 10/06/2021 |
| From: | Arizona Public Service Co |
| To: | Siva Lingam NRC/NRR/DORL/LPL4 |
| Lingam S, 301-415-1564 | |
| Shared Package | |
| ML21278B095 | List: |
| References | |
| EPID L-2021-LRM-0104 | |
| Download: ML21278B091 (12) | |
Text
Relief Request 68 Progressive Liquid Penetrant (PT) Alternative Pre-Submittal Meeting Palo Verde Nuclear Generating Station (PVNGS)
October 6, 2021
Introduction Relief Request Summary Current Requirements Alternative Requirements Alternative Justifications Duration of Proposed Alternatives Precedents Schedule Agenda
3 Reason for the request:
Personnel safety Eliminates Radiography Exposure Risk Outage support Eliminates impact outage activities Eliminates additional boundary and Radiation Protection (RP) support Eliminates additional engineering changes ALARA Radiography crew, RP, and boundary support personnel reduction Relief Request Summary
4 Current Requirements ISI Program is currently in the 4th Interval Current Section XI ASME BPV Code is the 2013 Edition Construction Code is ASME III 1974 edition Winter 1975 addenda For Repairs and ReplacementsSection XI refers to the Construction Code ASME Section III, NB and NC-5222, requires radiography (RT) of Class 1 and 2 circumferential weld joints in piping
5 Progressive PT examinations:
Examinations performed on the root pass, approximately mid-wall, and on the final weld profile Examination acceptance criteria of no indications would be required (commonly referred to as PT White)
Limited to ASME Class 1 and 2 circumferential piping welds 2 nominal pipe size and less in diameter Schedule 160 and less in thickness Alternative Requirements
6 No indications allowed Multiple examinations per weld Root pass, mid-wall, and final configuration ASME Section III partial penetration welds utilize this progressive examination technique Alternative provides additional margin when compared to 1:1 socket welds Alternative Justifications
7 Alternative Justifications
8 Alternative Justifications PT ROOT MID-WALL FINAL Socket Weld Cross Section Butt Weld Cross Section
9 Alternative will utilize PT White (no indications) compared to:
ASME Section III required radiography:
Limited detectability for small diameter welds Bevel angles for incomplete fusion Acceptance criteria allows elongated and rounded indications ASME Section III for Class 1 liquid penetrant:
Liquid penetrant has great detectability for surface indications Acceptance criteria allows unlimited indications <1/16 Rounded indications up to 3/16 allowed Alternative Justifications Side Wall IQI Wires Weld Cap Superimposed 3 views
10
- The proposed alternative is requested for the remainder of the fourth 10-year ISI interval for each of the PVNGS units.
- The end dates are:
Unit 1: July 17, 2028 Unit 2: October 31, 2028 Unit 3: January 10, 2028 Duration of Proposed Alternatives
11 Millstone, Unit 2, ADAMS Accession ML093570237 St. Lucie, Unit 1, ADAMS Accession ML17033A151 Precedents
12 APS is planning to submit in October 2021 NRC approval requested by September 2022 Schedule