ML063260245

Review of 2005 Annual Steam Generator Tube Inservice Inspection Report

ML063260245
Person / Time
Site:	Surry
Issue date:	11/21/2006
From:	Siva Lingam NRC/NRR/ADRO/DORL/LPLII-1
To:	Christian D Virginia Electric & Power Co (VEPCO)
Lingam, Siva NRR/DORL 415-1564
References
TAC MD0267
Download: ML063260245 (5)

Text

November 21, 2006 Mr. David A. Christian Senior Vice President and Chief Nuclear Officer Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

SURRY POWER STATION, UNIT NO. 2 - REVIEW OF 2005 ANNUAL STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT (TAC NO. MD0267)

Dear Mr. Christian:

By letter dated May 31, 2005, Virginia Electric and Power Company (the licensee) submitted the steam generator (SG) tube plugging report in accordance with Technical Specification (TS)

Section 4.19.F.a. By letter dated February 28, 2006, the licensee submitted the annual SG inspection report in accordance with TS Section 4.19.F.b. Additional information regarding the SG tube inservice inspections conducted during the 2005 refueling outage at Surry Power Station, Unit 2, was provided by the licensee in a letter dated August 2, 2006. The U. S.

Nuclear Regulatory Commission (NRC) staff reviewed the results of these inspection and plugging reports in order to determine whether additional follow-up activities were warranted.

Based on a review of the information provided by the licensee, the NRC staff concludes that the licensee has provided sufficient information to determine that there are not any issues that warrant additional follow-up at this time. The NRC staffs review of the licensees reports is enclosed.

Sincerely,

/RA/

Siva P. Lingam, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-281

Enclosure:

NRC Staff Review of 2005 Annual Steam Generator Inservice Inspection Summary Report cc w/encl: See next page

ML063260245 See memorandum dated August 25,2006 OFFICE NRR/LPL2-1/PM NRR/LPD2-1/LA NRR/DCI/CSGB/BC NRR/LPL2-1/BC NAME SLingam MOBrien AHiser* EMarinos DATE 11/20/06 11/20/06 08/25/06 11/21/06 NUCLEAR REGULATORY COMMISSION (NRC) STAFFS REVIEW OF 2005 ANNUAL STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT SURRY POWER STATION, UNIT NO. 2 DOCKET NO. 50-281 By letter dated May 31, 2005 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML051600111), Virginia Electric and Power Company (the licensee) submitted the steam generator (SG) tube plugging report in accordance with Technical Specification (TS) Section 4.19.F.a for Surry power Station, Unit No. 2 (Surry Unit 2). By letter dated February 28, 2006 (ADAMS Accession No. ML060600281), the licensee submitted the annual SG inspection report in accordance with TS Section 4.19.F.b. Additional information regarding the SG tube inservice inspections during the 2005 refueling outage (RFO) was provided by the licensee in a letter dated August 2, 2006 (ADAMS Accession No. ML062140360).

Surry Unit 2 has Westinghouse Model 51F SGs which are designated SGA through SGC. SGC and a small number of tubes in SGB were inspected during the 2005 RFO. The SGs contain approximately 3,342 thermally treated Alloy 600 tubes which have an outside diameter of 0.875 of an inch and a wall thickness of 0.050 of an inch. The tubes were hydraulically expanded at both ends for the full length of the tubesheet and are supported by a number of stainless steel tube support plates. The U-bends of the tubes installed in Rows 1 through 8 were thermally stress-relieved after bending.

The licensee provided the scope, extent, methods, and results of the Surry Unit 2 SG tube inservice inspections in the documents referenced above. In addition, the licensee described corrective actions (i.e., tube plugging) taken in response to the inspection findings.

The NRC staff has the following notes/observations as a result of reviewing the aforementioned documents submitted by the licensee:

• The SG tube eddy current vendor data acquisition system contains programs to verify data quality. In several inspections prior to the spring of 2005, this data quality verification was supplemented by evaluating the noise levels in the field eddy current data and comparing it to the noise levels in the Examination Technical Specification Sheet (ETSS). Starting with the spring 2005 RFO, the licensee began evaluating the noise in previous outage eddy current data to ensure that these noise levels were acceptable when compared to the value reported in the qualification database (i.e., the ETSS). The NRC staff notes while it is important to ensure inspection techniques are qualified prior to the outage (i.e, historical review of noise measurement values), it is equally important to monitor the noise levels each outage to assess if the noise levels are changing and if the noise levels remain within the original technique qualification.

• The licensee indicated that they used two sizing techniques during the 2005 RFO to estimate the dimensions of certain flaws (ETSS 21998.1 and ETSS 96910.1). The licensee indicated that ETSS 21998.1 is appropriate for sizing flaws less than 0.25 of an inch but produces overly conservative depth estimates for flaws greater than 0.25 of an inch. Although the licensee did not provide the supporting data for this conclusion, the licensee indicated that they used ETSS 21998.1 depth estimates to determine which tubes needed to be plugged and used ETSS 96910.1 depth estimates for the condition monitoring assessment.

• The annual report submitted by letter dated February 23, 2004 (ADAMS Accession No. ML040630162) by the licensee for Surry Power Station, Unit Nos. 1 and 2, RFO in 2003, stated that both units have denting in the peripheral tubes at the 6th and 7th tube support plates. Inspections confirmed that these dents tend to be located near tube support wedge locations in upper elevations of periphery tubes. The dents tend to be low voltage and are not expected to cause a significant increase in stresses to the tubes. No stress corrosion cracking has been identified at these locations. The licensee indicated that the 2005 inspection data showed that these dent signals experienced no significant increase from the 2000 inspection data. The 2000 inspection was the last inspection of SGC on the same reporting basis. These signals will continue to be monitored. Data from future inspections should serve as a tool to understanding the apparent denting phenomena.

Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by their TSs. 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.

Surry Power Station, Units 1 & 2 cc:

Ms. Lillian M. Cuoco, Esq. Office of the Attorney General Senior Counsel Commonwealth of Virginia Dominion Resources Services, Inc. 900 East Main Street Building 475, 5th Floor Richmond, Virginia 23219 Rope Ferry Road Waterford, Connecticut 06385 Mr. Chris L. Funderburk, Director Nuclear Licensing & Operations Support Mr. Donald E. Jernigan Dominion Resources Services, Inc.

Site Vice President Innsbrook Technical Center Surry Power Station 5000 Dominion Blvd.

Virginia Electric and Power Company Glen Allen, Virginia 23060-6711 5570 Hog Island Road Surry, Virginia 23883-0315 Senior Resident Inspector Surry Power Station U. S. Nuclear Regulatory Commission 5850 Hog Island Road Surry, Virginia 23883 Chairman Board of Supervisors of Surry County Surry County Courthouse Surry, Virginia 23683 Dr. W. T. Lough Virginia State Corporation Commission Division of Energy Regulation Post Office Box 1197 Richmond, Virginia 23218 Dr. Robert B. Stroube, MD, MPH State Health Commissioner Office of the Commissioner Virginia Department of Health Post Office Box 2448 Richmond, Virginia 23218