ML081970709
| ML081970709 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/23/2008 |
| From: | Moroney B NRC/NRR/ADRO/DORL/LPLII-2 |
| To: | Campbell W Tennessee Valley Authority |
| Moroney B, NRR/DORL, 415-3974 | |
| References | |
| GL-08-001, TAC MD7879, TAC MD7880 | |
| Download: ML081970709 (8) | |
Text
July 23, 2008 Mr. William R. Campbell, Jr.
Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 - GENERIC LETTER 2008-01, MANAGING GAS ACCUMULATION IN EMERGENCY CORE COOLING, DECAY HEAT REMOVAL, AND CONTAINMENT SPRAY SYSTEMS, PROPOSED ALTERNATIVE COURSE OF ACTION (TAC NOS. MD7879 AND D7880)
Dear Mr. Campbell:
On January 11, 2008, the Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems (Agencywide Documents Access and Management System (ADAMS) Accession No. ML072910759). The GL requested licensees to submit information to demonstrate that the emergency core cooling, decay heat removal, and containment spray systems are in compliance with the current licensing and design bases and applicable regulatory requirements, and that suitable design, operational, and testing control measures are in place for maintaining this compliance.
In accordance with Section 50.54(f) of Title 10 of the Code of Federal Regulations, GL 2008-01 required that each licensee submit the requested information within 9 months of the date of the GL. The GL also stated that if a licensee cannot meet the requested 9-month response date, the licensee is required to provide a response within 3 months of the date of the GL describing the alternative course of action it proposes to take and the basis for the acceptability of the proposed alternative course of action.
By letter dated June 6, 2008 (ADAMS Accession No. ML081630086), Tennessee Valley Authority, the licensee, submitted a revised 3-month response to GL 2008-01 for Sequoyah Nuclear Plant Units 1 and 2 (SQN-1 and SQN-2). The NRC staffs assessment of the licensees response is enclosed.
The NRC staff reviewed the licensees proposed alternative course of action and the associated basis for acceptance and concluded that they are acceptable for SQN-1 and SQN-2, with the exception of the clarifications and associated requests discussed in the enclosure. This letter allows the licensee to implement its proposed alternative course of action provided that implementation is consistent with the clarifications and associated requests discussed in the enclosure.
If you have any questions regarding this letter, please feel free to contact me at (301) 415-3974.
Sincerely,
/RA/
Brendan T. Moroney, Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-327 and 50-328
Enclosure:
As stated cc w/enclosures: See next page
If you have any questions regarding this letter, please feel free to contact me at (301) 415-3974.
Sincerely,
/RA/
Brendan T. Moroney, Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-327 and 50-328
Enclosure:
As stated cc w/enclosures: See next page DISTRIBUTION:
PUBLIC RidsOgcRp RidsNrrDprPgcb LPL2-2 R/F RidsAcrsAcnw&mMailCenter RidsNrrDss RidsNrrDorlLpl2-2 RidsRgn2MailCenter RidsNrrLACSola DBeaulieu, DPR/PGCB RidsNrrPMBMoroney SSun, DSS/SRXB RidsNrrDorlDPR WLyon, DSS/SRXB ADAMS Accession Number: ML081970709 NRR-106 OFFICE LPL2-2:PM LPL2-2:LA PGCB:BC DSS/DD LPL2-2:BC NAME BMoroney RSola MMurphy JWermeil BMozafari for TBoyce DATE 07/21/08 07/21/08 07/23/08 07/21/08 OFFICIAL RECORD COPY
Enclosure NRC STAFF ASSESSMENT OF 3-MONTH RESPONSE TO GENERIC LETTER 2008-01 SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 1.0
Background
On January 11, 2008, the Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems (Agencywide Documents Access and Management System (ADAMS) Accession No. ML072910759). The GL requested licensees to submit information to demonstrate that the emergency core cooling, decay heat removal, and containment spray systems (hereinafter referred to as the subject systems) are in compliance with the current licensing and design bases and applicable regulatory requirements, and that suitable design, operational, and testing control measures are in place for maintaining this compliance.
Specifically, the GL requested licensees to provide: (1) a description of the results of evaluations that were performed in response to the GL; (2) a description of all corrective actions that the licensee determined were necessary; and (3) a statement regarding which corrective actions were completed, the schedule for completing the remaining corrective actions, and the basis for that schedule.
In accordance with Section 50.54(f) of Title 10 of the Code of Federal Regulations, GL 2008-01 required that each licensee submit the requested information within 9 months (hereinafter referred to as the 9-month submittal) of the date of the GL. The GL also stated that if a licensee cannot meet the requested 9-month response date, the licensee is required to provide a response within 3 months (hereinafter referred to as the 3-month submittal) of the date of the GL, describing the alternative course of action it proposes to take, including the basis for the acceptability of the proposed alternative course of action.
2.0 Licensees Proposed Alternative Course of Action By letter dated June 6, 2008 (ADAMS Accession No. ML081630086), Tennessee Valley Authority (TVA), the licensee, submitted a revised 3-month response to GL 2008-01 for Sequoyah Nuclear Plant (SQN), Units 1 and 2 (SQN-1 and SQN-2). TVA indicated that SQN-1 and SQN-2 would complete within the requested 9 months a significant amount of the requested actions, including reviews of plant design, licensing basis documentation and system operating and testing procedures, and submit this information to the NRC by October 11, 2008. However, it indicated that for SQN-1 and SQN-2, the only GL 2008-01 reporting request that would not be completed by the requested response time is walkdowns of some segments of piping of the subject systems, including the Emergency Core Cooling System (ECCS), Residual Heat Removal (RHR), and Containment Spray System (CSS). The licensee cannot complete the walkdowns because portions of the subject systems are inaccessible during power operation due to the need to enter into the reactor building and/or radiation environments, to remove insulation from piping of the subject systems, to remove shielding or to erect scaffolding to obtain adequate access for the requested detailed inspections. For pipe located outside containment, most field walkdowns needed to determine pipe configuration details would be performed before October 11, 2008. The licensee identified that the following systems contain piping sections that will not be accessed until the next refueling outages because of the potential for high dose exposure or the need for extensive scaffolding:
Piping in the subject systems located outside the reactor building which is inaccessible because it is in a high radiation area or requires scaffolding for access, where erection of that scaffolding during operation could pose a risk to worker safety or to safe operation of the plant.
Piping in the reactor building annulus that is inaccessible because it is in a high radiation area or that requires scaffolding for access.
Safety Injection (SI) System discharge piping - containment penetration to reactor coolant loops.
SI System discharge piping - cold leg accumulator tanks to reactor coolant loops.
CSS and RHR Spray Systems discharge piping - containment penetration to riser.
Chemical Volume Control System discharge piping - containment penetration to reactor coolant loops.
RHR System suction and discharge piping - Containment penetration to reactor coolant loops.
These excluded portions may contain segments that are accessible without posing undue risks to operations of radiological/occupational safety. Such segments will be considered accessible, and will be included in the field walkdowns to be performed by October 11, 2008. The licensee indicated that GL 2008-01 adverse conditions discovered at Watts Bar Nuclear Plant Unit 1 (WBN-1) would be entered into the Corrective Action Program (CAP) and evaluated for applicability at SQN-1 and SQN-2 due to their design and construction similarity. The licensees CAP ensures that deficiencies identified at one unit will be considered for applicability to the other units.
As an alternative course of action, the licensees letter dated June 6, 2008, listed the following commitments:
(1)
Complete by October 11, 2008, GL 2008-01 actions for the subject systems, with the exception of the investigative or confirmatory walkdowns postponed until the next refueling outages for each unit. The next refueling outages are planned in the spring of 2009 and fall of 2009 for SQN-1 and SQN-2, respectively.
(2)
Complete the detailed walkdowns for SQN inaccessible piping sections of GL 2008-01 subject systems prior to startup after the next refueling outage for each unit.
(3)
Complete evaluations of GL 2008-01 subject systems using results of the detailed walkdowns of inaccessible piping sections and submit supplemental responses to NRC documenting completion of the walkdowns and any impact upon the GL 2008-01 nine month response as a result of completed evaluation within 90 days following startup from the next refueling outage for each unit.
(4)
Evaluate the applicability at SQN of the CAP that incorporated actions for the GL 2008-01 adverse conditions discovered at WBN-1 due to the design and construction similarities between the WBN-1 and SQN. The licensee stated that it has confidence the GL subject systems can fulfill their required design functions, based on its operating experience, which includes system walkdowns, detailed evaluations, and testing performed since plant licensing. In addition, the plant has performed modifications to install vents to intermediate high points in the ECCS and RHR system.
Existing plant procedures require venting the ECCS and RHR pumps on a 31-day frequency. Further, the licensee stated that by October 11, 2008, it will complete GL 2008-01 requested actions, with the exception of the confirmatory walkdowns that will be postponed until the next refueling outages that are planned in the spring of 2009 (SQN-1) and fall of 2009 (SQN-2). The outage walkdowns are expected to be validation activities of the design reviews for the subject systems.
Based on the above considerations, the licensee concluded that completing detailed walkdowns outside the required 9-month period, but no later than startup from the Spring 2009 and Fall 2009 refueling outages for SQN-1 and SQN-2, respectively, and submission of a supplemental response to the GL 90 days post-outage, is an acceptable course of action.
3.0 NRC Staff Assessment The NRC staff finds that, with the exception of the clarifications and associated requests discussed below, the licensees proposed alternative course of action is acceptable based on the above-described operating experience, procedures, and plant modifications associated with managing gas accumulation at SQN-1 and SQN-2. However, the NRC staff noted that the licensees 3-month submittal dated June 6, 2008, did not clearly describe the content for the 9-month submittals. The NRC staff requests that the licensee submit the information requested in the GL as follows:
(1) 9-Month Initial Submittal - For the portions of the subject systems that are accessible prior to the Spring 2009 and Fall 2009 refueling outages for SQN-1 and SQN-2, respectively, provide all GL requested information to the NRC by October 11, 2008.
(2) 9-Month Supplemental (Post-Outage) Submittal - Except for the long-term items described below, provide all remaining GL requested information for the subject systems to the NRC within 90 days following completion of the Spring 2009 and Fall 2009 refueling outages for SQN-1 and SQN-2, respectively.
For each of these two submittals (the 9-month initial and supplemental submittals), and consistent with the information requested in the GL, the licensees should provide: (1) a description of the results of evaluations that were performed in response to the GL; (2) a description of all corrective actions that the licensee determined were necessary; and (3) a statement regarding which corrective actions were completed, the schedule for completing the remaining corrective actions, and the basis for that schedule.
The NRC staff noted that the licensees submittal dated June 6, 2008, did not mention other potential long-term actions identified in the GL. For instance, the industry is assessing whether it is necessary to perform pump testing to determine the allowable limits on ingested gas volume in pump suction piping, as well as whether analysis development is needed to assess gas transport in the subject system piping as a function of system flow. It is unlikely that this industry effort will be completed before the 9-month initial or supplemental submittals. Further, technical specification changes may be necessary to reflect the improved understanding achieved during response to the GL, but these cannot be fully developed for the 9-month initial or supplemental submittals. A Technical Specifications Task Force traveler may provide a generic example that can be adopted by licensees. The NRC staff requests that the licensee address in its 9-month submittal how it plans to track such long-term actions (e.g., Corrective Action Program and/or commitment tracking). The NRC plans to perform followup inspections of licensee responses to GL 2008-01 at all plants using a Temporary Instruction inspection procedure.
William R. Campbell, Jr.
SEQUOYAH NUCLEAR PLANT Tennessee Valley Authority cc:
Mr. Ashok S. Bhatnagar Senior Vice President Nuclear Generation Development and Construction Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Vice President Nuclear Support Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. H. Rick Rogers Vice President Nuclear Engineering & Technical Services Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Timothy P. Cleary, Site Vice President Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000 General Counsel Tennessee Valley Authority 6A West Tower 400 West Summit Hill Drive Knoxville, TN 37902 Mr. John C. Fornicola, Manager Nuclear Assurance Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Ms. Beth A. Wetzel, Manager Corporate Nuclear Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. James D. Smith, Manager Licensing and Industry Affairs Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000 Mr. Christopher R. Church, Plant Manager Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000 Senior Resident Inspector Sequoyah Nuclear Plant U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, TN 37379 Mr. Lawrence E. Nanney, Director TN Dept. of Environment & Conservation Division of Radiological Health Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 County Mayor Hamilton County Courthouse Chattanooga, TN 37402-2801 Mr. Larry E. Nicholson, General Manager Performance Improvement Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael A. Purcell Senior Licensing Manager Nuclear Power Group Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Ms. Ann P. Harris 341 Swing Loop Road Rockwood, TN 37854