ML022750134
| ML022750134 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 10/02/2002 |
| From: | Stephen Monarque NRC/NRR/DLPM/LPD2 |
| To: | Christian D Virginia Electric & Power Co (VEPCO) |
| Monarque S, NRR/DLPM, 415-1544 | |
| References | |
| TAC MB4270, TAC MB4271 | |
| Download: ML022750134 (14) | |
Text
October 1, 2002 Mr. David A. Christian Senior Vice President and Chief Nuclear Officer Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, Virginia 23060
SUBJECT:
NORTH ANNA POWER STATION, UNITS 1 AND 2 - ISSUANCE OF AMENDMENTS RE: QUENCH SPRAY AND RECIRCULATION SPRAY NOZZLES SURVEILLANCE FREQUENCY (TAC NOS. MB4270 AND MB4271)
Dear Mr. Christian:
The Commission has issued the enclosed Amendment Nos. 233 and 215 to Facility Operating License Nos. NPF-4 and NPF-7 for the North Anna Power Station, Unit Nos. 1 and 2. The amendments change the Technical Specifications (TS) in response to your letter dated February 26, 2002, as supplemented by letter dated July 15, 2002.
These amendments revise the TS surveillance requirement (SR) 3.6.6.5 and SR 3.6.7.7 to change the frequency of inspection for the quench spray and recirculation spray nozzles.
A copy of the Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's biweekly Federal Register notice.
Sincerely, Stephen Monarque, Project Manager, Section 1 Project Directorate II /RA/
Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-338 and 50-339
Enclosures:
- 1. Amendment No. 233 to NPF-4
- 2. Amendment No. 215 to NPF-7
- 3. Safety Evaluation cc w/encls: See next page
October 1, 2002 Mr. David A. Christian Senior Vice President - Nuclear Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, Virginia 23060
SUBJECT:
NORTH ANNA POWER STATION, UNITS 1 AND 2 - ISSUANCE OF AMENDMENTS RE: QUENCH SPRAY AND RECIRCULATION SPRAY NOZZLES SURVEILLANCE FREQUENCY (TAC NOS. MB4270 AND MB4271)
The Commission has issued the enclosed Amendment Nos. 233 and 215 to Facility Operating License Nos. NPF-4 and NPF-7 for the North Anna Power Station, Unit Nos. 1 and 2. The amendments change the Technical Specifications (TS) in response to your letter dated February 26, 2002, as supplemented by letter dated July 15, 2002.
These amendments revise the TS surveillance requirement (SR) 3.6.6.5 and SR 3.6.7.7 to change the frequency of inspection for the quench spray and recirculation spray nozzles.
A copy of the Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's biweekly Federal Register notice.
Sincerely, Stephen Monarque, Project Manager, Section 1 Project Directorate II /RA/
Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-338 and 50-339
Enclosures:
- 1. Amendment No. 233 to NPF-4
- 2. Amendment No. 215 to NPF-7
- 3. Safety Evaluation cc w/encls: See next page Distribution: RidsAcrsAcnwMailCenter RidsRgn2MailCenter (KLandis)
PUBLIC SMonarque (paper copy) GHill (4 paper copies)
PDII-1 Rdg. EDunnington (paper copy) RidsNrrWBeckner RidsNrrDlpmLpdii RidsOgcRp RLobel SWeerakkodyML02 Accession: ML022750134 Package: ML022760006 TS Pages: ML022760129 *No major changes made to the SE OFFICE PM:PDII/S1 LA:PDII/S2 SC: SPLB* SC: RORP* OGC SC:PDII/S1 NAME SMonarque EDunnington SWeerakkody RDenning RHoefling JNakoski DATE 9/18/02 9/18/02 9/5 /02 8/9 /02 9/25/02 10/01/02 COPY Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No OFFICIAL RECORD COPY
VIRGINIA ELECTRIC AND POWER COMPANY DOCKET NO. 50-338 NORTH ANNA POWER STATION, UNIT NO. 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 233 License No. NPF-4
- 1. The Nuclear Regulatory Commission (the Commission) has found that:
A. The application for amendment by Virginia Electric and Power Company et al.,
(the licensee) dated February 26, 2002, as supplemented by letter dated July 15, 2002, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
- 2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility Operating License No. NPF-4 is hereby amended to read as follows:
(2) Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 233, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.
- 3. This license amendment is effective as of its date of issuance and shall be implemented within 30 days of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
John A. Nakoski, Chief, Section 1 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance: October 1, 2002
VIRGINIA ELECTRIC AND POWER COMPANY DOCKET NO. 50-339 NORTH ANNA POWER STATION, UNIT NO. 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 215 License No. NPF-7
- 1. The Nuclear Regulatory Commission (the Commission) has found that:
A. The application for amendment by Virginia Electric and Power Company et al.,
(the licensee) dated February 26, 2002, as supplemented by letter dated July 15, 2002, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
- 2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility Operating License No. NPF-7 is hereby amended to read as follows:
(2) Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 215, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.
- 3. This license amendment is effective as of its date of issuance and shall be implemented within 30 days from the date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
John A. Nakoski, Chief, Section 1 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance: October 1, 2002
ATTACHMENT TO LICENSE AMENDMENT NO. 233 TO FACILITY OPERATING LICENSE NO. NPF-4 LICENSE AMENDMENT NO. 215 TO FACILITY OPERATING LICENSE NO. NPF-7 DOCKET NOS. 50-338 AND 50-339 Replace the following pages of the Appendix "A" Technical Specifications and associated Bases with the enclosed pages as indicated. The revised pages are identified by amendment number and contain vertical lines indicating the areas of change.
Remove Pages Insert Pages 3.6.6-2 3.6.6-2 3.6.7-3 3.6.7-3 B 3.6.6-5 B 3.6.6-5 B 3.6.6-6 B 3.6.6-6 B 3.6.7-8 B 3.6.7-8
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 233 TO FACILITY OPERATING LICENSE NO. NPF-4 AND AMENDMENT NO. 215 FACILITY OPERATING LICENSE NO. NPF-7 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-338 AND 50-339
1.0 INTRODUCTION
By letter dated February 26, 2002, as supplemented by letter dated July 15, 2002, Virginia Electric and Power Company (the licensee) requested license amendments for North Anna Power Station, Units 1 and 2, to change the periodic testing of the Quench Spray (QS) and Recirculation Spray (RS) System nozzles from once every 10 years to whenever maintenance is conducted that could result in nozzle blockage. The supplemental letter dated July 15, 2002, provided clarifying information only and did not change the staffs original proposed no significant hazards consideration determination or expand the scope of the application as originally noticed.
The licensees proposed amendments revise Surveillance Requirement (SR) 3.6.6.5 and SR 3.6.7.7 for the QS System nozzles and RS System nozzles, respectively. Currently, SR 3.6.6.5 and SR 3.6.7.7 require the QS and RS spray nozzles to be inspected once every 10 years to ensure that these systems are free of blockage. Testing is performed by an air or smoke flow test to verify that the spray nozzles are not obstructed. The proposed amendments would change the surveillance frequency from 10 years to Following maintenance which could cause nozzle blockage.
2.0 REGULATORY EVALUATION
The staff has identified the regulatory requirements, which are listed below.
Section 182a of the Atomic Energy Act requires applicants for nuclear power plant operating licenses to include technical specifications (TS) as part of the license. These TS were derived from the plant safety analyses. Licensees may revise the TS provided a plant-specific review supports a finding of continued adequate safety. A change that is less restrictive than the licensees current requirement may be justified if it still affords adequate assurance of safety when judged against current regulatory standards. The staffs determination on whether the proposed changes maintain safety is contained in section 3.0.
The staff reviewed the proposed changes for compliance with Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36 and NUREG-1431, Standard Technical Specifications for
Westinghouse Plants, which specifies that the QS and RS systems nozzle flow surveillance be performed once every 10 years. In determining the acceptability of the licensees proposed changes, the staff reviewed and interpreted the requirements of 10 CFR 50.36, using as a model the accumulation of generically approved guidance in NUREG-1431. NUREG-1431 incorporates the general guidance and limiting conditions for operation scoping criteria provided by the Commissions Final Policy Statement on Technical Specification Improvement for Nuclear Power Reactors, published in the Federal Register on July 23, 1993 (58 FR 39132) and incorporated in 10 CFR 50.36, effective August 18, 1995.
3.0 TECHNICAL EVALUATION
The staff has reviewed the licensees regulatory and technical analyses in support of its proposed license amendment that are described in the February 26, 2002, submittal, as supplemented by letter dated July 15, 2002. The detailed evaluation below will support the conclusion that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
The containment depressurization system is used to return the containment atmosphere to subatmospheric pressure after a loss-of-coolant accident (LOCA) by removing heat from the containment structure. The containment depressurization system consists of two subsystems:
(1) the QS subsystem, and (2) the RS subsystem. The QS subsystem transfers heat from the containment atmosphere to the quench spray, which is collected in the containment sump. The RS subsystem transfers heat, via the RS coolers, from the water collected on the containment floor and from the containment atmosphere to the service water system. The QS and RS subsystems are further divided into two trains each.
Each QS train contains a 100-percent capacity pump and a 360-degree quench spray ring header located approximately 100 feet above the operating floor in the dome of the containment structure. The ring headers each have 260 nozzle sites. The piping is fabricated of Type 304 stainless steel and the spray nozzles are brass. Because of the corrosion-resistant material chosen for the spray nozzles, degradation of the spray nozzles is not expected. Every eleventh nozzle is a capped spare leaving 239 actual installed nozzles. The QS pumps are located in the safeguards area, an enclosure adjacent to the containment structure.
The QS pump discharge motor-operated valves (MOVs) and weighted check valves are maintained closed during normal operation to provide containment isolation. Each QS supply line to the containment contains a weight-loaded check valve to prevent air inleakage to the containment when it is at subatmospheric pressure. One-quarter-inch drain lines, located downstream of the check valves inside containment, will drain the QS manifolds should any water enter the manifolds during periodic testing. In addition, each train of QS has a 4-inch line downstream of the isolation valves that supplies water to the suction of the RS pumps for increased net positive suction head. The 4-inch line would also serve to prevent any water collection in the supply headers. Containment sump inleakage is monitored and recorded in the control room during plant operation, which provides another method to identify any leak-by of the QS and RS MOVs.
Each RS train consists of two 50-percent capacity pumps (one inside containment, one outside containment) and their associated RS coolers, and 180-degree spray ring headers located approximately 85 feet above the operating floor of the containment structure. All piping and ring headers are constructed of Type 304 stainless steel and the spray nozzles are brass.
Because of the corrosion-resistant material chosen for the spray nozzles, degradation of the spray nozzles is not expected.
Strainers are provided in the discharge of the QS pumps. Three layers of screening are provided in the suction of the RS pumps. The strainers and the screen mesh are small enough to prevent any material that could plug the nozzles from passing through.
The staff examined the performance history of the systems at North Anna, failure mechanisms of spray nozzles revealed by past performance at North Anna as well as at other plants, and the effectiveness of the air or smoke flow test with respect to those failure mechanisms. Based on these examinations, the staff concluded that the impact of the proposed changes on the system reliability is negligible.
Performance History at North Anna In its application, the licensee stated that a smoke/air test was performed at each unit at least twice on the QS and RS systems nozzles since construction. The results of each test demonstrated unobstructed flow through each nozzle. These tests confirmed that the systems were free from construction debris and obstructions following startup and operation of the units.
In response to the NRC staffs request, the licensee provided additional information on pre-operational testing of spray nozzles at North Anna, Units 1 and 2. The licensees July 15, 2002, letter provides a detailed description of the pre-operational testing that was done to ensure that no debris remained in the spray systems at plant startup of both units. This pre-operational testing included water flow through the spray headers followed by air flow testing of the nozzles.
The license stated that review of the maintenance and modification history since the last smoke/air test indicated a limited number of work orders and modifications have been performed on QS and RS MOV isolation valves or the system piping. The modifications associated with the valves were for operator adjustment and would not have affected system cleanliness. The maintenance activities included: repositioning the spectacle flange and elbows for RS testing activities, repair and adjustment of weighted discharge check valves, installing blanks on QS piping to support MOV leak testing, and RS heat exchanger inspections.
Cleanliness control practices, including post-work inspections, were used and documented in the work order to ensure system cleanliness requirements were maintained.
Industry experience and failure mechanisms Review of industry experience using the NRCs Sequence Coding and Search System for Licensee Event Reports indicates that spray systems of similar design are highly reliable (i.e.,
not susceptible to plugging). The staff reviewed industry experience and found that containment spray nozzles, once tested after construction, have not generally been subject to blockage. There have been several exceptions. In the case of one pressurized-water reactor (PWR), a chemical was added to the inner surface of a spray system pipe to eliminate a
corrosion problem. This resulted in loose material blocking some spray nozzles. Spray piping in PWRs, and in particular at North Anna, is corrosion resistant; therefore, this failure mechanism is not applicable to North Anna. The licensee for another PWR found debris, identified as construction debris, in the spray nozzle headers. The fraction of blockage was not significant and the sprays remained functional. The debris was found by visual observation, not by an air flow test.
Other problems have been identified in containment spray and fire protection systems in which water leakage resulted in corrosion that resulted in some, but not complete, blockage. As described above, the North Anna design effectively precludes this condition. The spray ring headers are maintained dry and are made of corrosion-resistant stainless steel, therefore, formation of significant corrosion products is precluded.
Due to their location at the top of the containment, introduction of foreign material exterior to the headers is unlikely. Since maintenance that could introduce foreign material is the most likely cause for obstruction, testing or inspection following such maintenance would suffice to verify the potential for nozzle(s) blockage and the systems capability to perform its safety function.
These reasons make the potential for nozzle obstruction very low; therefore, the 10-year test frequency is unnecessary. Verifying that the nozzles are not obstructed following maintenance that could introduce foreign materials to the spray ring headers is a more appropriate frequency. This verification would consist of an inspection of the nozzles, or a flow test using air or smoke.
Based on its review of the plant-specific and industry performance history as described above, the staff concludes that the design of the North Anna containment depressurization system, combined with the licensees Post Maintenance Testing Program to address nozzle blockage when performing maintenance on the system, will minimize the potential for nozzle blockage.
Although the proposed SR frequency may result in less spray nozzle testing, the licensee will perform testing directly after maintenance that is likely to cause nozzle blockage. This provides confidence in system operability and affords adequate assurance of safety. The staff, therefore, concludes that the licensees proposed TS change, which modifies the frequency of verifying the QS and RS nozzles are unobstructed, from once every 10 years to following maintenance which could cause nozzle blockage, is acceptable.
4.0 STATE CONSULTATION
In accordance with the Commissions regulations, the Virginia State official was notified of the proposed issuance of the amendment on September 30, 2002. Mr. Les Foldesi, Program Director for the Commonwealth of Virginia, Radiological Health Department, provided the following comments regarding the proposed issuance of the amendment:
Relaxing the schedule of the nozzle inspections would affect the systems ability to remove iodine. In addition, this appears to be inconsistent with the NRCs concern regarding the release of iodine.
The staffs response to the above comments is as follows.
Section 6.2.1.1 of the North Anna Updated Final Safety Analysis Report, which provides the design basis to limit the consequences of a LOCA, states that the containment depressurization can be accomplished by one out of two trains of the QS system and one out of two trains of the
RS system. The licensees submittal dated July 15, 2002, provided additional information on the pre-operational tests that were conducted at North Anna. This included water flush tests with the nozzles removed followed by air testing of the installed nozzles. Theses tests removed any construction debris that was present. Subsequent smoke and air tests performed by the licensee have not identified any nozzle blockage. The licensee has not opened the QS or RS spray rings for maintenance, testing, or inspection. In addition, the licensees foreign material exclusion program would prevent the introduction of debris into these systems. The ability of North Anna to remove iodine during accident scenarios will not be affected as there are no changes to the design of these systems.
5.0 ENVIRONMENTAL CONSIDERATION
These amendments change surveillance requirements. The staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (67 FR 21296). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: B. LeFave R. Lobel P. Hearn Date: October 1, 2002
Mr. David A. Christian North Anna Power Station Virginia Electric and Power Company Units 1 and 2 cc:
Mr. C. Lee Lintecum Mr. David A. Heacock County Administrator Site Vice President Louisa County North Anna Power Station P.O. Box 160 P.O. Box 402 Louisa, Virginia 23093 Mineral, Virginia 23117-0402 Ms. Lillian M. Cuoco, Esq.
Senior Nuclear Counsel Mr. Richard H. Blount, II Dominion Nuclear Connecticut, Inc. Site Vice President Millstone Power Station Surry Power Station Building 475, 5th Floor Virginia Electric and Power Company Rope Ferry Road 5570 Hog Island Road Rt. 156 Surry, Virginia 23883-0315 Waterford, Connecticut 06385 Dr. W. T. Lough Robert B. Strobe, M.D., M.P.H.
Virginia State Corporation State Health Commissioner Commission Office of the Commissioner Division of Energy Regulation Virginia Department of Health P.O. Box 1197 P. O. Box 2448 Richmond, Virginia 23209 Richmond, Virginia 23218 Old Dominion Electric Cooperative Mr. William R. Matthews 4201 Dominion Blvd. Vice President - Nuclear Operations Glen Allen, Virginia 23060 Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Boulevard Mr. Stephen P. Sarver, Director Glen Allen, Virginia 23060-6711 Nuclear Licensing & Operations Support Virginia Electric and Power Company Mr. Les Foldesi Innsbrook Technical Center Program Director, Radiological Health 5000 Dominion Blvd. Virginia Department of Health Glen Allen, Virginia 23060-6711 Room 240 P.O. Box 2448 Richmond, Virginia 23218 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 1024 Haley Drive Mineral, Virginia 23117