ML112010532
| ML112010532 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 07/28/2011 |
| From: | Geoffrey Miller Plant Licensing Branch 1 |
| To: | Freeman P, O'Keefe M NextEra Energy Seabrook |
| Miller G, NRR/DORL/LPL1-2, 415-2481 | |
| References | |
| TAC ME5715 | |
| Download: ML112010532 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 July 28, 2011 Mr. Paul Freeman, Site Vice President c/o Michael O'Keefe Seabrook Station NextEra Energy Seabrook, LLC P.O. Box 300 Seabrook, NH 03874 SUB..IECT:
SUMMARY
OF STEAM GENERATOR TUBE MID-INSPECTION CONFERENCE CALL FOR SPRING 2011 - SEABROOK STATION, UNIT NO.1 (TAC NO. ME5715)
Dear Mr. Freeman:
By letter dated March 10,2011 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML110480846) the Nuclear Regulatory Commission (NRC) provided discussion pOints to facilitate a conference call regarding the steam generator tube inspections during the last outage for Seabrook Station, Unit No.1. On April 15, 2011, the conference call was conducted, and enclosed with this letter is a summary of that call. Based on the information provided, the NRC staff did not identify any issues that required follow-up.
If you have any questions regarding this matter, I may be reached at 301-415-2481.
Si/~(v)'1 G~~~ Miller, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-443
Enclosure:
As stated cc w/encl: Distribution via ListServ
SUMMARY
OF CONFERENCE CALL STEAM GENERATOR TUBE INSPECTION REPORT FOR SPRING 2011 SEABROOK STATION, UNIT NO.1 DOCKET NO. 50-443 On April 15, 2011, the staff of the Steam Generator Tube Integrity and Chemical Engineering Branch of the Division of Component Integrity participated in a conference call with NextEra Energy, LLC (the licensee) representatives regarding the ongoing steam generator (SG) tube inspection activities at Seabrook Station.
Seabrook has four Westinghouse Model F SGs, each of which contains 5,626 thermally treated Alloy 600 tubes. Each tube has a nominal outside diameter of 0.688 inches and a nominal wall thickness of 0.040 inches. During SG fabrication, the tubes were hydraulically expanded, at both ends, over the full depth of the tubesheet. Type 405 stainless steel support plates, which have broached quatrefoil holes, support the vertical section of the tubes, and anti-vibration bars support the U-bend section of the tubes.
Information provided by the licensee is summarized below:
During the 2011 outage, the only tube inspections planned for the SGs were a 20 percent sample in SGs A, Band D, and a 100 percent sample in SG C. These inspections were required by Seabrook plant technical specification 5.7.6.d.3 in response to outside diameter stress corrosion cracking (ODSCC) indications found at the top-of tubesheet (TTS) during the previous refueling outage (refueling outage 13). These inspections are at the TTS, from 3 inches above to 3 inches below the TTS and are performed with a +Point rotating pancake coil.
- At the time of the call, the licensee stated that no ODSCC or primary water stress corrosion cracking indications were reported and that the tube inspections for SGs Band C were complete. The 20 percent sample inspections in SGs A and D were starting on April 15, 2011, and projected to be complete on April 16, 2011.
- The primary-to-secondary leakage for SG B was reported to be 0.5 gallons per day (gpd) with a spike of 1 gpd at the end-of-cycle, which was attributed to shutting down for the refueling outage (RFO). The 0.5 gpd leak in SG B has been steady and unchanging for multiple fuel cycles.
No secondary side pressure tests were performed.
No exceptions to industry guidelines were taken.
Enclosure
-2
- The licensee reported that there were no new volumetric indications. Three historic volumetric indications were observed to have not changed from the last RFO. In SG B, one indication was confirmed to be 19 percent through-wall and in SG C, two indications were confirmed to be 9 and 21 percent through-wall.
- The licensee stated that there were no plans for plugging any tube in the current RFO.
- The licensee stated that there were no plans to perform in situ testing or tube pulls.
- The licensee performed a pre-Advanced Scale Conditioning Agents (ASCA) lancing of SG C and removed 30 Ibs of sludge. This was followed by the ASCA cleaning which removed 7 Ibs of sludge, and then a post-ASCA lancing was performed and 50 Ibs of sludge was removed.
- At the time of the call, the licensee had found no unusual or unexpected results.
The licensee expected to complete SG inservice inspection on April 19, 2011.
- The licensee performed a foreign object search and retrieval in SG C and reported that a dumbbell-shaped foreign object, which was originally identified in RFO 1, was observed and reported to be lodged in the same location. This object could not be retrieved.
Additionally, a nail shaped object, which was originally identified in RFO 11, was retrieved. Also, one piece of soft scale, which initially looked like a foreign object, broke up when retrieval was attempted.
The NRC staff did not identify any issues that required follow-up action at this time; however, the staff asked to be notified in the event that any unusual conditions were detected during the remainder of the outage.
- via email LPL 1-2/PM LPL 1-2/LA CSGB/BC MYoderfor OFFICE NAME GEMiller ABaxter
- RTaylor**
HChernoff DATE 7/27/11 7/22/11 5/18/11 7/28/11