ML121240840
| ML121240840 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 05/03/2012 |
| From: | Balwant Singal Plant Licensing Branch IV |
| To: | Hope T Luminant Generation Co |
| Singal, Balwant, 415-3016, NRR/DORL/LPL4 | |
| Shared Package | |
| ML121240816 | List: |
| References | |
| TAC ME7789 | |
| Download: ML121240840 (2) | |
Text
ENCLOSURE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR ADDITIONAL INFORMATION RELIEF REQUEST NO. A-2 FOR THE UNIT 2 SECOND 10 YEAR ISI INTERVAL FROM 10 CFR 50.55a INSPECTION REQUIREMENTS DUE TO GEOMETRIC LIMITATIONS LUMINANT GENERATION COMPANY, LLC COMANCHE PEAK NUCLEAR POWER PLANT, UNIT 2 DOCKET NO. 50-446 By letter dated January 5, 2012, (Reference 1), supplementing letter dated December 18, 2006, (Reference 2), Luminant Generation Company, LLC, (the licensee) submitted Relief Request A-2 for the Unit 2 Second 10 Year inservice inspection (ISI) Interval from Title 10 of the Code of Federal Regulations (10 CFR) 50.55a Inspection Requirements Due to Geometric Limitations for Comanche Peak Nuclear Power Station, Unit 2. In the relief requests the licensee proposes a shorter examination distance below the toe of the J-groove weld than that required by the First Revised Order EA-03-009 (Order, Reference 3) or that of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) Case N-729-1, as required and conditioned by 10 CFR Part 50, paragraph (g)(6)(ii)(D). The licensee states that the control rod drive mechanism (CRDM) penetration nozzle numbers 74 through 78 cannot be volumetrically examined to the extent required due to the threaded region on the outside diameter and the chamfer on the inside diameter of the penetration nozzles. The licensee also states that the sleeve design of CRDM penetration nozzles 63 and 65 does not permit inspection with currently available equipment. In order to complete our review, the staff requests further information.
- 1. Please provide the start date and expected end date of the second inservice inspection (ISI) interval.
- 2. Describe any relevant indications from the CRDM ultrasonic examination (UT) performed in refueling outage 2RF12.
- 3. ASME Code Case N-729-1 requires inspection of the penetration nozzle to a distance a below the lowest point of the J-groove weld. This exam coverage can be attained by UT, surface examination or a combination or the two. Please estimate the radiological dose associated with performing a surface examination to attain the required coverage for penetration nozzles 74 through 78.
- 4. Penetration nozzles 74 through 78 were examined in refueling outage 2RF12 in spring of 2011. For each of these nozzles:
- a. Please provide the J-groove weld as-designed and as-built dimensions
- b. Please provide the UT examination distance below lowest point of the as-built J-groove weld toe for both the axial and circumferential flaws
- 5. Was the analysis of Westinghouse Commercial Atomic Power report (WCAP)-16397-P (Reference 4) based on the as-designed or as-built J-groove weld dimensions? If the analysis was based on the as-designed dimensions, please demonstrate that it bounds the analysis of the as-built dimensions;
- 6. The 2.25 RIY period for CRDM nozzles 63 and 65 includes 2RF13 in fall of 2013 when the inspection is expected to be successfully performed. Please explain why relief is being requested for inspection of these nozzles.
References
- 1. Letter dated January 5, 2012, Relief Request A-2 for the Unit 2 Second 10 Year ISI Interval from 10 CFR 50.55a Inspection Requirements Due to Geometric Limitations, Agencywide Documents Access and Management System (ADAMS) Accession Number ML12017A126
- 2. Letter dated December 18, 2006, Update to 60-Day Response to Revision 1 of NRC Order EA-03-009, Issuance of First Revised NRC Order (EA-03-009) Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads At Pressurized Water Reactors, ADAMS Accession Number ML063630152
- 3. First Revised NRC Order (EA-03-009) Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors, Issued February 20, 2004, ADAMS Accession Number ML040220181
- 4. Westinghouse Topical Report WCAP-16397-P, Structural Integrity Evaluation of Reactor Vessel Upper Head Penetration to Support Continued Operations: Comanche Peak Units 1 and 2, ADAMS Accession Number ML063630186