ML111360998
| ML111360998 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 05/16/2011 |
| From: | Balwant Singal Plant Licensing Branch IV |
| To: | Hope T Luminant Generation Co |
| Singal, B K, NRR/DORL, 301-415-301 | |
| Shared Package | |
| ML111360831 | List: |
| References | |
| TAC ME5217, TAC ME5218 | |
| Download: ML111360998 (2) | |
Text
Enclosure REQUEST FOR ADDITIONAL INFORMATION REQUEST FOR RELIEF B-10 and B-11 RELATED TO RISK-INFORMED PIPING EXAMINATIONS LUMINANT GENERATION COMPANY LLC COMANCHE PEAK NUCLEAR POWER PLANT, UNIT 1 DOCKET NUMBER: 50-445 By letter dated December 15, 2010, Luminant Generation Company (the licensee) requested relief from certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI requirements. Relief Requests (RRs) B-10 and B-11 pertain to the use of an alternative to the risk-informed piping examinations for the second 10-year inservice Inspection Interval for Comanche Peak Nuclear Power Plant, Unit 1. To complete its review, the U.S. Nuclear Regulatory Commission (NRC) staff requests for the following additional information.
- 1. Please provide material specifications for the weld TBX-1-4201-9 and TBX-1-4201-10 and associated pipe and elbow in RR B-10. Provide the material specifications for weld TBX-1-4300-13 and safe end, in RR B-11.
- 2. It appears that the subject welds in RR B-10 are associated with the safety injection system piping. However, the examination sheets identify the piping system as accumulator discharge. Please identify the exact piping systems for subject welds in RRs B-10 and B-11.
- 3. For RR B-10, would it be possible to remove the structural restraints to increase the examination coverage? Please clarify.
- 4. For RR B-10, did Luminant Generation Company LLC consider using longitudinal waves to examine past the centerline in the area currently limited from examination, thus increasing the examination coverage? Please clarify.
- 5. Section 3 of RR B-10 states that The subject pipe size is 10 and Table IWB-2500-1 calls for a surface examination of the weld Please discuss whether a surface examination has been performed in the inside or outside surface of the subject welds. If no, please justify why a surface examination was not performed.
- 6. Please provide the inspection history (inspection dates, methods used, and Non Destructive Examination results) of the subject welds in RRs B-10 and 11.
- 7. For RRs B-10 and B-11, please discuss whether new Ultrasonic Testing (UT) technology (e.g., phased-array UT) has been considered which may provide higher percentage of examination coverage than the existing UT technology. If yes, please discuss whether the new UT technology will be used in the next in-service inspection. If no, please discuss why new UT technology was not explored.
- 8. For RR B-11, please provide illustrations of the weld configuration that identifies the examined weld area/volume and the weld area/volume that was not examined.
Specifically describe how the configuration or obstruction restricts full examination of the weld. The configuration should include the reactor vessel nozzle, safe end, weld, pipe, and counter-bore.