ML101880047
| ML101880047 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 07/07/2010 |
| From: | Jacqueline Thompson Plant Licensing Branch II |
| To: | Morris J Duke Energy Carolinas |
| Thompson, Jon 415-1119 | |
| References | |
| TAC ME2302 | |
| Download: ML101880047 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 7, 2010 Mr. J. R. Morris Site Vice President Catawba Nuclear Station Duke Energy Carolinas, LLC 4800 Concord Road York, SC 29745 SUB..IECT:
CATAWBA NUCLEAR STATION, UNIT 2 (CATAWBA 2) - REVIEW OF THE 2009 STEAM GENERATOR (SG) TUBE INSPECTIONS DURING REFUELING OUTAGE 16 END OF CYCLE (EOC 16) (TAC NO. ME2302)
Dear Mr. Morris:
By letter dated July 14, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML092010498), Duke Energy Carolinas, LLC (the licensee), submitted information summarizing the results of the 2009 SG tube inspections at Catawba 2. These inspections were performed during EOC 16. Additional information concerning the 2009 SG tUbe inspections at Catawba 2 was provided by the licensee in letters dated May 28, 2009 (ADAMS Accession No. ML091550027), and May 20, 2010 (ADAMS Accession No. ML101470067).
The Nuclear Regulatory Commission (NRC) staff has completed its review of the submittal and concludes that the licensee provided the information required by the Catawba 2 technical specifications. No additional follow-up is required at this time. The NRC staff's review is enclosed.
If you have any questions, please call me at 301-415-1119.
Sincerely, Jon Thompson, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-414
Enclosure:
As stated cc w/encl: Distribution via Listserv
STAFF EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO RESULTS OF 2009 STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING REFUELING OUTAGE 16 CATAWBA NUCLEAR STATION, UNIT 2 DOCKET NO. 50-414 By letter dated July 14, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML09201049B), Duke Energy Carolinas, LLC (the licensee), submitted information summarizing the results of the 2009 steam generator (SG) tube inspections at Catawba Nuclear Station, Unit 2 (Catawba 2). These inspections were performed during refueling outage 16 End of Cycle (EOC 16). Additional information concerning the 2009 SG tube inspections at Catawba 2 was provided by the licensee in letters dated May 2B, 2009 (ADAMS Accession No. ML091550027), and May 20, 2010 (ADAMS Accession No. ML101470067).
Catawba 2 has four Westinghouse Electric Company Model D5 SGs, which are designated 2A through 2D. All four SGs were inspected during the EOC 16 refueling outage. Each SG has 4,570 thermally-treated Alloy 600 tubes with an outside diameter of 0.750-inch and a nominal wall thickness of 0.043-inch. The tubes are hydraulically expanded for the full-depth of the tubesheet at each end. The tubes are supported by Type 405 stainless steel support plates with quatrefoil-shaped holes. The U-bend region of the tubes installed in Rows 1 through 9 was thermally-treated after bending in order to reduce stress.
The licensee provided the scope, extent, methods, and results of the Catawba 2 SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (Le., tube plugging) taken in response to the inspection findings.
It was reported that eight indications of axial outside diameter stress-corrosion cracking (ODSCC) were observed at the hot-leg tube support plate intersections of three tubes. Two of these tubes were considered high stress tubes (Le., -2 sigma on both legs), while the third tube only had -2 sigma on one leg. The four Catawba 2 SGs contain 65 tubes (130 legs) that are considered high stress. To date, four of these tubes have been plugged, including two tubes for indications at tube support plate locations, one tube for a tube end indication, and one tube for an indication in the preheater region.
No ODSCC was observed at the top of the tubesheet during the EOC 16 outage. ODSCC indications had been detected (and plugged) in the prior outage.
The licensee indicated that visual inspections were performed to determine the extent of tube support plate hole blockage during the EOC 16 outage. The EOC 16 inspections indicated that the broached openings at the OB-hot and 09-cold support plates were generally open and free of blockage. There was some evidence of deposits beginning to form at the bottoms of broached openings. In addition, a small number of openings were partially blocked by "spalled" flakes.
Enclosure
- 2 Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by their technical specifications. In addition, the NRC staff concludes that there are no technical issues that warrant follow-up action at this time since the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units.
July 7,2010 Mr. J. R. Morris Site Vice President Catawba Nuclear Station Duke Energy Carolinas, LLC 4800 Concord Road York, SC 29745
SUBJECT:
CATAWBA NUCLEAR STATION, UNIT 2 (CATAWBA 2) - REVIEW OF THE 2009 STEAM GENERATOR (SG) TUBE INSPECTIONS DURING REFUELING OUTAGE 16 END OF CYCLE (EOC 16) (TAC NO. ME2302)
Dear Mr. Morris:
By letter dated July 14, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML092010498), Duke Energy Carolinas, LLC (the licensee), submitted information summarizing the results of the 2009 SG tube inspections at Catawba 2. These inspections were performed during EOC 16. Additional information concerning the 2009 SG tube inspections at Catawba 2 was provided by the licensee in letters dated May 28, 2009 (ADAMS Accession No. ML091550027), and May 20, 2010 (ADAMS Accession No. ML101470067).
The Nuclear Regulatory Commission (NRC) staff has completed its review of the submittal and concludes that the licensee provided the information required by the Catawba 2 technical specifications. No additional follow-up is required at this time. The NRC staff's review is enclosed.
If you have any questions, please call me at 301-415-1119.
Sincerely, IRA!
Jon Thompson, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-414
Enclosure:
As stated cc w/encl: Distribution via Listserv DISTRIBUTION:
PUBLIC RidsNrrDorlLpl2-1 Resource RidsRgn2MailCenter Resource LPL2-1 R/F KKarwoski, NRR/DCI RidsNrrLAMOBrien Resource (hard copy)
RidsAcrsAcnw_MailCTR Resource AJohnson, NRR/DCI/CSGB RidsNrrPMCatawba Resource (hard copy)
RidsNrrDciCsgb Resource RidsOgcRp Resource ADAMS Accesslon No. ML101880047
- no Sl. ~n1'fiIcant change 0 memo ML101650068 OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA NRR/CSGB/BC NRR/LPL4/BC NRR/LPL2-1/PM NAME JThompson MO'Brien (SUttle for)
RTaylor*
GKulesa JThompson DATE 6/30/10 7/1/10 6/14/10 7/710 7/7/10 OFFICIAL RECORD COpy