ML081900661: Difference between revisions
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| issue date = 07/10/2008 | | issue date = 07/10/2008 | ||
| title = /2, 2007 Refueling Outage Steam Generator Inspections (TAC Nos. MD7490 and MD7491) | | title = /2, 2007 Refueling Outage Steam Generator Inspections (TAC Nos. MD7490 and MD7491) | ||
| author name = Lingam S | | author name = Lingam S | ||
| author affiliation = NRC/NRR/ADRO/DORL/LPLII-1 | | author affiliation = NRC/NRR/ADRO/DORL/LPLII-1 | ||
| addressee name = Christian D | | addressee name = Christian D | ||
| addressee affiliation = Virginia Electric & Power Co (VEPCO) | | addressee affiliation = Virginia Electric & Power Co (VEPCO) | ||
| docket = 05000338, 05000339 | | docket = 05000338, 05000339 | ||
| Line 81: | Line 81: | ||
The licensee provided the scope, extent, methods, and results of the North Anna 1 and 2 SG tube 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 licensee provided the scope, extent, methods, and results of the North Anna 1 and 2 SG tube 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 U.S. Nuclear Regulatory Commission (NRC) staff has the following notes as a result of reviewing the aforementioned submittals: | The U.S. Nuclear Regulatory Commission (NRC) staff has the following notes as a result of reviewing the aforementioned submittals: | ||
: 1. In North Anna 1, only SG "A" was inspected during the 2007 outage. In North Anna 2, SGs "A" and "C" were inspected during the 2007 outage. 2. Wear indications were identified in a small number of tubes. These indications were at the tube support plate elevations. In North Anna 2, one of the indications went from no detectable degradation in 2001 to 40-percent through-wall in 2007. 3. Secondary side inspections of the SG upper internals were performed during the 2007 outages. In the 3 SGs inspected (as discussed above), a small clearance was noted between some of the moisture separator drain pipes and their corresponding supporting bracket. This clearance permits slight movement between the pipe and the bracket, however, there was no appreciable wear at the interface between the pipe and the bracket. The condition was evaluated by the | : 1. In North Anna 1, only SG "A" was inspected during the 2007 outage. In North Anna 2, SGs "A" and "C" were inspected during the 2007 outage. 2. Wear indications were identified in a small number of tubes. These indications were at the tube support plate elevations. In North Anna 2, one of the indications went from no detectable degradation in 2001 to 40-percent through-wall in 2007. 3. Secondary side inspections of the SG upper internals were performed during the 2007 outages. In the 3 SGs inspected (as discussed above), a small clearance was noted between some of the moisture separator drain pipes and their corresponding supporting bracket. This clearance permits slight movement between the pipe and the bracket, however, there was no appreciable wear at the interface between the pipe and the bracket. The condition was evaluated by the | ||
Revision as of 09:26, 12 July 2019
| ML081900661 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 07/10/2008 |
| 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 MD7490, TAC MD7491 | |
| Download: ML081900661 (5) | |
Text
July 10, 2008
Mr. David A. Christian President and Chief Nuclear Officer Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711
SUBJECT:
NORTH ANNA POWER STATION, UNIT NOS. 1 AND 2, 2007 REFUELING OUTAGE STEAM GENERATOR TUBE INSPECTIONS (TAC NOS. MD7490 AND MD7491)
Dear Mr. Christian:
By letters dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073200234), and October 9, 2007 (ADAMS Accession No.
ML072820576), Virginia Electric and Power Company, Inc. (the licensee), submitted steam generator tube inspection reports for the North Anna Power Station, Unit No. 1, fall 2007 refueling outage and the North Anna Power Station, Unit No. 2, spring 2007 refueling outage, respectively.
Additional information regarding the 2007 steam generator tube inspections was provided by the licensee in a letter dated March 18, 2008 (ADAMS Accession No. ML080790343).
The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review of these reports and concludes that the licensee provided the information required by their technical specifications and that no additional follow-up is required at this time. The NRC staff review of the 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 Nos. 50-338 and 50-339
Enclosure:
Inspection Summary Report
cc w/encl: See next page
ML072820576), Virginia Electric and Power Company, Inc. (the licensee), submitted steam generator tube inspection reports for the North Anna Power Station, Unit No. 1, fall 2007 refueling outage and the North Anna Power Station, Unit No. 2, spring 2007 refueling outage, respectively.
Additional information regarding the 2007 steam generator tube inspections was provided by the licensee in a letter dated March 18, 2008 (ADAMS Accession No. ML080790343).
The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review of these reports and concludes that the licensee provided the information required by their technical specifications and that no additional follow-up is required at this time. The NRC staff review of the 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 Nos. 50-338 and 50-339
Enclosure:
Inspection Summary Report
cc w/encl: See next page
DISTRIBUTION:
Public RidsNrrLAMO
=BrienResource (hard copy) RidsNrrDciCsgb(AHiser) RidsAcrsAcnw_MailCTRResource LPL2-1 R/F RidsNrrDorlLpl2-1Resource (MWong)
RidsOgcRpResource RidsNrrDciCsgbResource (AObodoako)
RidsNrrPMSLingamResource (hard copy)
RidsRgn2MailCenterResource (EGuthrie)
RidsNrrDciCsgbResource (KKarwoski)
ADAMS Accession No. ML081900661 *transmitted by memo dated OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA NRR/DCI/CSGB/BC NRR/LPL2-1/BC NAME SLingam MO
=Brien AHiser MWong DATE 7/10/08 7/10/08 6/16/08*
7/10/08
Enclosure OFFICE OF NUCLEAR REACTOR REGULATION REVIEW OF THE 2007 REFUELING OUTAGE STEAM GENERATOR TUBE INSPECTION REPORTS NORTH ANNA POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-338 AND 50-339
By letters dated November 15, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML073200234), and October 9, 2007 (ADAMS Accession No.
ML072820576), Virginia Electric and Power Company, Inc. (the licensee), submitted steam generator (SG) tube inspection reports for the North Anna Power Station, Unit No. 1 (North Anna 1), fall 2007 refueling outage and the North Anna Power Station, Unit No. 2 (North Anna 2), spring 2007 refueling outage, respectively. Additional information regarding the 2007 steam generator tube inspections was provided by the licensee in a letter dated March 18, 2008 (ADAMS Accession Number ML080790343).
North Anna 1 and 2 each have three Westinghouse Model 54F replacement steam generators, each containing 3592 thermally treated Alloy 690 tubes. These SGs were replaced in 1993 and 1995, respectively. The tubes have an outside diameter of 0.875 inches, a wall thickness of 0.050 inches, and are supported by 7 stainless steel tube support plates and a baffle plate. Most of the tube support plate holes are quatrefoil-shaped. The U-bend region of the tubes in rows 1 through 8 was stress relieved after bending.
The licensee provided the scope, extent, methods, and results of the North Anna 1 and 2 SG tube 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 U.S. Nuclear Regulatory Commission (NRC) staff has the following notes as a result of reviewing the aforementioned submittals:
- 1. In North Anna 1, only SG "A" was inspected during the 2007 outage. In North Anna 2, SGs "A" and "C" were inspected during the 2007 outage. 2. Wear indications were identified in a small number of tubes. These indications were at the tube support plate elevations. In North Anna 2, one of the indications went from no detectable degradation in 2001 to 40-percent through-wall in 2007. 3. Secondary side inspections of the SG upper internals were performed during the 2007 outages. In the 3 SGs inspected (as discussed above), a small clearance was noted between some of the moisture separator drain pipes and their corresponding supporting bracket. This clearance permits slight movement between the pipe and the bracket, however, there was no appreciable wear at the interface between the pipe and the bracket. The condition was evaluated by the
licensee and the licensee concluded that this condition will not impact tube integrity prior to the next inspection after 3 fuel cycles of operation. 4. In SG "A" of North Anna 1, ultrasonic thickness measurements of the feedring were taken. The measurements and subsequent analysis of the data (and previous data) by the licensee indicated that the minimum acceptable wall thickness at the most limiting location would not be reached for an additional 5 operating cycles. 5. Visual inspections of the upper SG bundle region in the 3 SGs inspected (as discussed above) indicated light to moderate deposit buildup at various locations.
All broached tube support plate holes viewed were open, with some evidence of light deposit coating on the walls of the broached hole.
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 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.
North Anna Power Station, Units 1 & 2
cc:
Mr. David A. Christian President and Chief Nuclear Officer Virginia Electric and Power Company Innsbrooks Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711
Mr. C. Lee Lintecum County Administrator Louisa County Post Office Box 160 Louisa, Virginia 23093
Ms. Lillian M. Cuoco, Esq.
Senior Counsel Dominion Resources Services, Inc.
120 Tredegar Street, RS-2 Richmond, VA 23219
Dr. W. T. Lough Virginia State Corporation Commission Division of Energy Regulation Post Office Box 1197 Richmond, Virginia 23218
Old Dominion Electric Cooperative 4201 Dominion Blvd.
Glen Allen, Virginia 23060
Mr. Chris L. Funderburk, Director Nuclear Licensing & Operations Support Dominion Resources Services, Inc.
Innsbrook Technical Center 5000 Dominion Blvd.
Glen Allen, Virginia 23060-6711
Office of the Attorney General Commonwealth of Virginia 900 East Main Street Richmond, Virginia 23219
Senior Resident Inspector North Anna Power Station U. S. Nuclear Regulatory Commission P. O. Box 490 Mineral, Virginia 23117
Mr. Daniel G. Stoddard Site Vice President North Anna Power Station Virginia Electric and Power Company Post Office Box 402 Mineral, Virginia 23117-0402
Dr. Robert B. Stroube, MD, MPH State Health Commissioner Office of the Commissioner Virginia Department of Health Post Office Box 2448 Richmond, Virginia 23218
Mr. Eric Hendrixson, Director Nuclear Safety & Licensing Virginia Electric and Power Company North Anna Power Station P.O. Box 402 Mineral, VA 23117