ML060960158

Summary of the Staff'S Review of the Steam Generator Tube Inspection 15-Day and 90-Day Reports for End-of-Cycle 12 Refueling Outage in 2005

ML060960158
Person / Time
Site:	Sequoyah
Issue date:	05/01/2006
From:	Pickett D Plant Licensing Branch III-2
To:	Singer K Tennessee Valley Authority
Pickett D, NRR/DLPM, 415-1364
References
TAC MC8118
Download: ML060960158 (5)

Text

May 1, 2006 Mr. Karl W. Singer Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

SEQUOYAH NUCLEAR PLANT, UNIT 2

SUMMARY

OF THE STAFFS REVIEW OF THE STEAM GENERATOR TUBE INSPECTION 15-DAY AND 90-DAY REPORTS FOR END-OF-CYCLE 13 REFUELING OUTAGE IN 2005 (TAC NO. MC8118)

Dear Mr. Singer:

By letter dated May 31, 2005, (Agencywide Documents Access and Management System Accession Number, ML051600187), Tennessee Valley Authority (TVA, the licensee) submitted the 15-day steam generator (SG) tube plugging report in accordance with Technical Specification (TS) 4.4.5.5.a. By letter dated August 15, 2005 (ML052340503), TVA submitted the 90-day SG voltage-based alternate repair criteria and W* report in accordance with Sequoyah Nuclear Plant (SQN), Unit 2, License Condition 2.C.(8)(b). By letter dated February 22, 2006 (ML060540467), the licensee provided additional information concerning these reports. In addition to these reports, the Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2005 SG tube inspection in a letter dated June 7, 2005 (ML051810694).

The NRC staff has completed its review of these reports and concludes that the licensee provided the information required by SQN, Unit 2 TSs, and that no additional followup is required at this time. The staffs review of the reports is enclosed.

Sincerely,

/RA/

Douglas V. Pickett, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-328

Enclosure:

Staffs Review cc w/encl: See next page

ML060960158 NRR-106 OFFICE LPL2-2 LPL2-2/PM LPL2-2/LA DCI/CSGB LPL2-2/BC NAME SCrane DPickett RSola EMurphy (by memo) MMarshall DATE 04/28/06 04/28/06 04/28/06 03/10/06 05/1/06 Mr. Karl W. Singer SEQUOYAH NUCLEAR PLANT Tennessee Valley Authority cc:

Mr. Ashok S. Bhatnagar, Senior Vice President Mr. Glenn W. Morris, Manager Nuclear Operations Corporate Nuclear Licensing Tennessee Valley Authority and Industry Affairs 6A Lookout Place Tennessee Valley Authority 1101 Market Street 4X Blue Ridge Chattanooga, TN 37402-2801 1101 Market Street Chattanooga, TN 37402-2801 Mr. Larry S. Bryant, Vice President Nuclear Engineering & Technical Services Mr. Paul L. Pace, Manager Tennessee Valley Authority Licensing and Industry Affairs 6A Lookout Place ATTN: Mr. James D. Smith 1101 Market Street Sequoyah Nuclear Plant Chattanooga, TN 37402-2801 Tennessee Valley Authority P.O. Box 2000 Mr. Robert J. Beecken, Vice President Soddy Daisy, TN 37384-2000 Nuclear Support Tennessee Valley Authority Mr. David A. Kulisek, Plant Manager 6A Lookout Place Sequoyah Nuclear Plant 1101 Market Street Tennessee Valley Authority Chattanooga, TN 37402-2801 P.O. Box 2000 Soddy Daisy, TN 37384-2000 Mr. Randy Douet Site Vice President Senior Resident Inspector Sequoyah Nuclear Plant Sequoyah Nuclear Plant Tennessee Valley Authority U.S. Nuclear Regulatory Commission P.O. Box 2000 2600 Igou Ferry Road Soddy Daisy, TN 37384-2000 Soddy Daisy, TN 37379 General Counsel Mr. Lawrence E. Nanney, Director Tennessee Valley Authority Division of Radiological Health ET 11A Dept. of Environment & Conservation 400 West Summit Hill Drive Third Floor, L and C Annex Knoxville, TN 37902 401 Church Street Nashville, TN 37243-1532 Mr. John C. Fornicola, Manager Nuclear Assurance and Licensing County Mayor Tennessee Valley Authority Hamilton County Courthouse 6A Lookout Place Chattanooga, TN 37402-2801 1101 Market Street Chattanooga, TN 37402-2801 Ms. Ann P. Harris 341 Swing Loop Road Rockwood, Tennessee 37854

SUMMARY

OF THE STAFFS REVIEW OF SEQUOYAH NUCLEAR PLANT, UNIT 2 STEAM GENERATOR TUBE INSPECTION 15-DAY AND 90-DAY REPORTS FOR THE END-OF CYCLE 13 REFUELING OUTAGE DOCKET NO. 50-328 By letter dated May 31, 2005, (Agencywide Documents Access and Management System Accession Number, ML051600187), Tennessee Valley Authority (TVA, the licensee) submitted the 15-day steam generator (SG) tube plugging report in accordance with Technical Specification 4.4.5.5.a. By letter dated August 15, 2005 (ML052340503), TVA submitted the 90-day SG voltage-based alternate repair criteria and W* report in accordance with Sequoyah Nuclear Plant (SQN), Unit 2, License Condition 2.C.(8)(b). By letter dated February 22, 2006 (ML060540467), the licensee provided additional information concerning these reports. In addition to these reports, the Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2005 SG tube inspection in a letter dated June 7, 2005 (ML051810694).

SQN, Unit 2 has Westinghouse Model 51 SGs, which are designated SG1, SG2, SG3, and SG4. All four SGs were inspected during the May 2005 refueling outage. The Westinghouse Model 51 SG consists of approximately 3300 tubes, which have an outside diameter of 7/8-inch and a wall thickness of 0.050-inch. The tubes were explosively expanded into the tubesheet and are supported by several 3/4-inch carbon steel tube support plates, which contain drilled holes through which the tubes pass.

The licensee implements alternate tube repair criteria for degradation within the tubesheet region (W*) and for outside diameter stress corrosion cracking at the tube support plate elevations.

The licensee provided the scope, extent, methods, and results of their SG tube inspections for implementation of these alternate tube repair criteria in the documents referenced above. The licensee also described corrective actions (e.g., tube plugging) taken in response to the inspection findings.

As a result of the review of the reports, the NRC staff has the following comment/observation:

The licensee indicated that indications of outside diameter stress corrosion cracking that were detected at the tube support plate elevations at the end-of-cycle 13, which did not have a corresponding end-of-cycle 12 indication, were not included in the growth rate determination. This practice is permitted as discussed in Section 2.b.2(2) of Attachment 1 to Generic Letter 95-05 provided the indication does not change from nondetectable to a relatively high voltage (e.g., 2.0 volts). For the end-of-cycle 13

inspections at SQN, Unit 2 there were no such indications (i.e., those that went from non-detectable to a relatively high voltage).

Based on a review of the information provided (i.e., regarding implementation of the alternate tube repair criteria), 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 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.

Principal Contributor: K. Karwoski Date: May 1, 2006