ML100150760
| ML100150760 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 01/15/2010 |
| From: | Thadani M Plant Licensing Branch IV |
| To: | Harrison A South Texas |
| Thadani, M C, NRR/DORL/LPL4, 415-1476 | |
| References | |
| TAC ME1618 | |
| Download: ML100150760 (2) | |
Text
From:
Thadani, Mohan Sent:
Friday, January 15, 2010 2:04 PM To:
Harrison, Albon Cc:
Morgan, Thomas
Subject:
Request for Additional Information-STP, Unit 2 Steam Generator Tube Inspection (TAC No. ME1618)
Wayne:
The NRC staff has reviewed your steam generator tube inspection report, dated March 24, 2009, for fall 2008 refueling outage 2E13 for STP, Unit 2.
Based on the review, the NRC staff has determined that additional information is required in order to complete its evaluation. Please respond to the following request for additional information within 30 days to facilitate timely completion of the NRC staff's evaluation.
If you have any questions, please contact me at (301) 415-1476, or email Mohan.Thadani@nrc.gov..
Mohan C Thadani Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation (301) 415-1476 Mohan.Thadani@nrc.gov REQUEST FOR ADDITIONAL INFORMATION 2008 STEAM GENERATOR TUBE INSPECTIONS SOUTH TEXAS PROJECT UNIT 2 DOCKET NUMBER 50-499 By letter dated March 24, 2009 (ML090970281), South Texas Project Electric Generating Station, (the licensee), submitted information summarizing the results of the Fall 2008 steam generator tube inspections performed at South Texas Project (STP) Unit 2. These inspections were performed during the thirteenth refueling outage (2RE13). In order to complete its review of the document listed above, the staff needs the following additional information:
In the 2RE13 steam generator (SG) tubing inservice inspection report dated March 24, 2009, the licensee stated that, This inspection was not required by STP Technical Specification (TS)
Section 6.8.3.0 for maintaining steam generator tube integrity and therefore is not for surveillance credit. The 2008 refueling outage was the third since the previous steam generator tube inspections were performed in 2004, and therefore South Texas Project Unit 2 was required to perform steam generator tube inspections to comply with TS 6.8.3.o.d.2 during the refueling outage in 2008. Considering the above information, please clarify the meaning of the referenced statement made in the March 24, 2009 SG tube inspection report.
Please discuss the findings from the following steam generator secondary side inspections performed during the 2008 refueling outage:
Sludge collector pumping and video probe inspection (2D only)
Video probe inbundle inspection at the 9th tube support plate - (2A [HL] only)
Steam drum inspection (2C and 2D only)
Upper steam drum inspection and steam nozzle inspection (2D only)
Tube scale profiling (2B and 2C only)
In particular, discuss any degradation identified during these inspections.
Four tubes were plugged as a result of loose parts that could not be removed. Please discuss whether these tubes were stabilized.
TS 6.9.1.7.g states that the SG tube inspection report shall include, The results of condition monitoring, including the results of tube pulls and in-situ testing. Please provide the results of any tube pulls and/or in-situ testing performed during 2RE13.
For each steam generator tube inspection outage since the replacement of the steam generators, please provide the effective full power months of operation that the SGs had accumulated at the time of the outage. It was indicated that no confirmed indications of tube degradation as defined by the Electric Power Research Institute (EPRI) steam generator examination guidelines were identified. The EPRI guidelines indicate, in part, that degradation is a flaw whose depth is 20-percent through-wall or greater. Please discuss whether any service-induced flaws, regardless of depth, were identified during your inspections. Include in this response the location, orientation, size, and cause of the indication. For the 4-percent through-wall, volumetric flaw at a support structure, please discuss the cause of this indication (e.g., tube support plate wear).