ML063380371

Summary of Conference Call Regarding the Spring 2006 Steam Generator Tube Inspection Activities

ML063380371
Person / Time
Site:	Surry
Issue date:	12/04/2006
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 MD2420
Download: ML063380371 (5)

Text

December 4, 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. 1 -

SUMMARY

OF CONFERENCE CALL REGARDING THE SPRING 2006 STEAM GENERATOR TUBE INSPECTION ACTIVITIES (TAC NO. MD2420)

Dear Mr. Christian:

On May 10, 2006, the Nuclear Regulatory Commission staff participated in a conference call with Surry Power Station, Unit No. 1 (Surry Unit 1), representatives regarding the spring 2006 steam generator tube inspection activities. The conference call was in response to receiving notification that a tube experienced leakage during an in-situ pressure test. A follow-up call with Surry Unit 1 representatives was made on May 11, 2006. A summary of these conference calls is enclosed for your information.

If you have any questions, please contact me at 301-415-1564.

Sincerely,

/RA/

Siva P. Lingam, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-280

Enclosure:

As stated cc w/encl: See next page

ML063380371 See memorandum dated November 1, 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 / 21 /06 11 / 30 /06 11/1/06 12 /04 /06 NUCLEAR REGULATORY COMMISSION STAFF CONFERENCE CALL

SUMMARY

REGARDING SPRING 2006 STEAM GENERATOR TUBE INSERVICE INSPECTION ACTIVITIES SURRY POWER STATION, UNIT NO. 1 DOCKET NO. 50-280 On May 10, 2006, Nuclear Regulatory Commission (NRC) staff participated in a conference call with the Surry Power Station, Unit No. 1 (Surry Unit 1), licensee regarding the spring 2006 steam generator (SG) tube inspection activities. The call was in response to receiving notification that a tube experienced leakage during an in-situ pressure test. A follow-up call was made on May 11, 2006. The conference calls are summarized below.

During the spring 2006 refueling outage, eddy current inspections of SG A and SG C were performed. An eddy current inspection of the SG B tubes was last performed in 2003.

However, secondary-side visual inspections (including in-bundle column inspections) were performed in all three SGs.

Eddy current testing revealed a cluster of tubes in SG A with flaws caused by a loose part. A secondary-side visual inspection revealed the loose part to be a nut which was subsequently removed. At the time of the call, the licensee was not sure where the nut originated from. Two tubes containing the largest flaw indications were in-situ pressure-tested (tube row (R)35 and column (C)69 and tube R35C68). Other tubes in the same vicinity having loose part flaws were not in-situ pressure-tested because the flaws were determined not to challenge the tube integrity performance criteria. The affected tubes were reported to be located approximately 12 to 14 tubes in from the periphery.

The licensee indicated that tube R35C69 passed the in-situ pressure test. For this test, the tube is pressurized to 5200 pounds per square-inch (psi), equivalent to 3 times the normal operating pressure (3P) under hot conditions, for 2 minutes without leakage.

The licensee reported that tube R35C68 did not experience leakage at normal differential pressure and main steamline break differential pressure; however, leakage was detected for this tube starting at approximately 4650 psi. The leakage rate reached 0.08 gallons per minute (gpm) when the applied pressure reached the maximum test pressure of 5200 psi. The licensee held this pressure for 5 minutes before terminating the test. During the 5-minute hold, the leakage continued to increase, reaching 0.98 gpm at the end of the 5-minute hold at 5200 psi. Based on the ability to hold 5200 psi for 5 minutes, the licensee concluded that the test successfully demonstrated the ability of the tube to sustain 3P without burst. Following the in-situ pressure tests, the licensee conducted a secondary-side inspection (SSI) to ensure Enclosure

no tubes were damaged during the tests. The licensee indicated that they plugged and stabilized tubes R35C68, R35C69, and additional tubes in the same vicinity.

During the call, the NRC staff expressed concerns regarding whether or not the licensee adequately demonstrated that the tube met 3P, given that the leakage rate had not fully stabilized prior to termination of the test. The NRC staff is concerned whether the industry in-situ pressure test guidelines adequately address this situation. During a meeting with industry representatives at a Nuclear Energy Institute meeting on July 12, 2006, the NRC staff requested that the industry evaluate this issue.

The licensee indicated that SG A, including tube R35C68, was last inspected during the 2001 refueling outage. In addition, the licensee reported that this wear indication should have been called using the bobbin probe data analysis guidelines existing at that time.

The licensee did not reevaluate the 2003 eddy current data for SG B. However, the licensee performed an SSI on SG B and no foreign objects were reported. Similarly, no foreign objects were reported for SG C for this outage.

The licensee provided the following additional information regarding the 2006 SG tube inspections:

• All three SGs were installed in the early 1980s and have exhibited no prior leaks, no active corrosion mechanisms, and the anti-vibration bar (AVB) inspection results are encouraging. There were 25 to 30 AVB wear indications for SG A which showed only slight growth.

• The licensee performed sludge lancing for SG A and SG C during this outage. In addition, during this outage, the licensee used an inter-bundle lance system. This is a new Areva method that is reported to be more effective than regular sludge lancing along the open tube lane.

• The licensee contributed the low number of loose parts to the feed regulator system valves that are cage valves, which make good strainers.

• The licensee indicated that any time something is found during an SSI, the SSI inspection scope is expanded.

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