ML13353A595
| ML13353A595 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 01/14/2014 |
| From: | Andrew Hon Plant Licensing Branch II |
| To: | James Shea Tennessee Valley Authority |
| Andy Hon, NRR/DORL | |
| References | |
| TAC MF2337 | |
| Download: ML13353A595 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Joseph W. Shea Vice President, Nuclear Licensing Tennessee Valley Authority 11 01 Market Street, LP 3D-C Chattanooga, TN 37402-2801 January 14, 2014
SUBJECT:
WATTS BAR NUCLEAR PLANT, UNIT 1-REVIEW OF THE STEAM GENERATOR TUBE INSERVICE INSPECTIONS FOR CYCLE 11 REFUELING OUTAGE IN 2012 (TAG NO. MF2337)
Dear Mr. Shea:
By letters dated April 19 and November 22, 2013 (Agencywide Documents Access and Management System Accession Nos. ML131150048 and ML13333A162), Tennessee Valley Authority (TVA) submitted information pertaining to the 2012 (Cycle 11) steam generator (SG) tube inspections performed at Watts Bar Nuclear Plant (WBN), Unit 1.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information that TVA provided and concludes that TVA provided the information required by WBN Unit 1 Technical Specifications and that no additional followup is required at this time. The NRC staff review of the SG portions of the reports is enclosed.
If you have any questions regarding this issue, please contact me at (301) 415-8480.
Docket No. 50-390
Enclosure:
As stated cc w/encl: Distribution via Listserv Sincerely, lh I j,
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Andrew Hon, Project Manager Licensing Project Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 OFFICE OF NUCLEAR REACTOR REGULATION REVIEW STEAM GENERATOR TUBE INSPECTION REPORT FOR CYCLE 11 WATTS BAR NUCLEAR PLANT. UNIT 1 TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-390 By letters dated April 19 and November 22, 2013 (Agencywide Documents Access and Management System Accession Nos. ML131150048 and ML13333A162), Tennessee Valley Authority (the licensee) submitted information pertaining to the 2012 steam generator (SG) inspections performed at Watts Bar Nuclear Plant, Unit 1. These inspections were performed during the eleventh refueling outage (RF011 ).
The four Model 68AXP SGs at Watts Bar Nuclear Plant, Unit 1, were designed by Westinghouse, fabricated by Doosan Heavy Industry and Construction, and installed in 2006. Each SG contains 5128 thermally treated Alloy 690 tubes. Each tube has a nominal outside diameter of 0. 75 inches and a nominal wall thickness of 0.043 inches. The tubes were hydraulically expanded at both ends for the full depth of the tubesheet. The SGs have an integral preheater. The tubes are supported by type 409 stainless steel lattice grids and some of the lattice grids only support a fraction of the tubes. The tubes installed in rows 1 through 38 were thermally stress relieved over their entire length, after bending.
The licensee provided the scope, extent, methods, and results of their SG tube inspections in the document referenced above. In addition, the licensee described corrective actions (e.g., tube plugging) taken in response to the inspection findings.
Based on its review of the reports submitted, the Nuclear Regulatory Commission (NRC) staff has the following observations and comments:
As of RF011, the SGs had operated for approximately 5.25 effective full power years since replacement. This was the second inservice inspection of these SGs.
Eighty wear indications were detected in 58 tubes. All of these indications were located at vertical or diagonal straps in the U-bend, or in the lattice structure of the Advanced Tube Support Grids. Fourteen of these 58 tubes were plugged. The deepest indication had an estimated depth of 32 percent through-wall.
Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by the technical specifications.
In addition, the staff concludes there are no technical issues that warrant followup 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.
Enclosure
Mr. Joseph W. Shea Vice President, Nuclear Licensing Tennessee Valley Authority 1101 Market Street, LP 3D-C Chattanooga, TN 37402-2801
SUBJECT:
WATTS BAR NUCLEAR PLANT, UNIT 1 -REVIEW OF THE STEAM GENERATOR TUBE INSERVICE INSPECTIONS FOR CYCLE 11 REFUELING OUTAGE IN 2012 (TAC NO. MF2337)
Dear Mr. Shea:
By letters dated April 19 and November 22, 2013 (Agencywide Documents Access and Management System Accession Nos. ML131150048 and ML13333A162), Tennessee Valley Authority (TVA) submitted information pertaining to the 2012 (Cycle 11) steam generator (SG) tube inspections performed at Watts Bar Nuclear Plant (WBN), Unit 1.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information that TVA provided and concludes that TVA provided the information required by WBN Unit 1 Technical Specifications and that no additional followup is required at this time. The NRC staff review of the SG portions of the reports is enclosed.
If you have any questions regarding this issue, please contact me at (301) 415-8480.
Docket No. 50-390
Enclosure:
As stated Sincerely, IRA/
Andrew Hon, Project Manager Licensing Project Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation cc w/encl: Distribution via Listserv DISTRIBUTION:
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