ML100710737
| ML100710737 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 03/12/2010 |
| From: | Hall J Plant Licensing Branch IV |
| To: | Stroud R Arizona Public Service Co |
| Hall, J R, NRR/DORL/LPL4, 301-415-4032 | |
| Shared Package | |
| ML100710725 | List: |
| References | |
| TAC ME2132 | |
| Download: ML100710737 (2) | |
Text
ENCLOSURE DRAFT REQUEST FOR ADDITIONAL INFORMATION ARIZONA PUBLIC SERVICE COMPANY, ET. AL.
PALO VERDE NUCLEAR GENERATING STATION, UNIT 1 DOCKET NO. STN 50-528 REQUEST FOR RELIEF NO. 46 TAC NO. ME2132 By letter dated July 17, 2009, Arizona Public Service Company (the licensee), submitted Relief Request No. 46 (RR 46), for the second 10-year inservice inspection (ISI) interval, pursuant to paragraph 50.55a(g)(5)(iii) of Title 10 of The Code of Federal Regulations (10 CFR). Request 46 is a request for relief from the ISI requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI for several ASME Code Class 1 and 2 components for the Palo Verde Nuclear Generating Station, Unit 1 (Palo Verde 1).
The U.S. Nuclear Regulatory Commission (NRC) staff requests that the licensee provide additional information to regarding RR 46, as follows:
- 1.
In part A of RR 46, the licensee indicated that the reactor vessel nozzle-to-vessel welds received volumetric examinations, with an overall combined examination volume that was limited to 82.5 percent of that required by the ASME Code,Section XI. Please discuss the results of these limited volumetric examinations, including whether any relevant indications were found during these examinations.
- 2.
In part B of RR 46, the licensee indicated that the integrally welded attachments on the pressurizer received surface examinations of only the outside surface of the attachment weld, whereas the ASME Code,Section XI requires surface examinations of both the outside surface and inside surface of these welds. The licensee also indicated that supplemental volumetric examinations were performed by ultrasonic testing (UT).
Please discuss the results of these outside surface examinations and supplemental UT examinations, including whether any relevant indications were found during these examinations.
- 3.
In part C of RR 46, the licensee listed a number of ASME Code,Section XI, Examination Category B-J circumferential piping welds that were credited with receiving only single-sided volumetric examinations based on the ASME Code,Section XI, Appendix VIII Performance Demonstration Initiative (PDI) criteria. Please discuss the results of these single-sided volumetric examinations and surface examinations performed on these welds, including whether any relevant indications were found during these examinations.
- 4.
In part D of RR 46, the licensee stated that the surface examinations of ASME Code,Section XI, Examination Category C-C piping support attachment welds could not achieve the ASME Code-required coverages. Please provide more detail on the extent of coverage that was obtained for each Category C-C weld identified in the submittal and
ENCLOSURE discuss the results of these surface examinations, including whether any relevant indications were found during these examinations.
- 5.
In part E of RR 46, the licensee stated that the ASME Code,Section XI, Examination Category C-C pump attachment welds referenced in the request received an average overall surface examination coverage of 78%, with 100% coverage of the rear lug attachments, and coverage limited at the bottom side of the front lug attachment. Please specify the percentage surface examination coverage obtained for the front lug attachment welds, and discuss the results of the surface examinations for all four attachment welds (front and rear), including whether any relevant indications were found during these examinations.
- 6.
In part F of RR 46, the licensee listed a number of ASME Code,Section XI, Examination Category C-F-1 circumferential piping welds that were credited with receiving only single-sided volumetric examinations based on the ASME Code,Section XI, Appendix VIII PDI criteria. Please discuss the results of these single-sided volumetric examinations and surface examinations performed on these welds, including whether any relevant indications were found during these examinations.