ML13018A053
| ML13018A053 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/25/2013 |
| From: | Siva Lingam Plant Licensing Branch II |
| To: | James Shea Tennessee Valley Authority |
| Lingam, Siva | |
| References | |
| TAC ME9238, TAC ME9239 | |
| Download: ML13018A053 (7) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 25, 2013 Mr. Joseph W. Shea Vice President, Nuclear Licensing Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING REVISION OF THE UPDATED FINAL SAFETY ANALYSIS REPORT TO ADOPT A REVISED HYDROLOGIC ANALYSIS (TAC NOS. ME9238 AND ME9239)
Dear Mr. Shea:
By letter dated August 10, 2012, you submitted an application for license amendment to revise the Updated Final Safety Analysis Report to adopt a revised hydrologic analysis for Sequoyah Nuclear Plant, Units 1 and 2 sites. These proposed changes are consistent with the latest approved hydrology calculations. The proposed changes in the updated hydrologic analysis include revised input information, and updates to methodology that include the use of the U.S.
Army Corps of Engineers Hydrologic Modeling System and River Analysis System software.
The U.S. Nuclear Regulatory Commission staff is reviewing the submittal and has determined that additional information is required to complete its evaluation. This request was discussed with Mr. Clyde Mackaman of your staff on January 17, 2013. and it was agreed that a response would be provided within 45 days from the date of this letter.
If you have any questions regarding this matter, I can be reached at 301-415-1564.
Sincerely,
~lf'~
Siva P. Lingam, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION REGARDING UPDATED FINAL SAFETY ANALYSIS REPORT CHANGES ASSOCIATED WITH HYDROLOGIC ANALYSIS SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 By letter dated August 10, 2012 (Agencywide Documents Access and Management System Accession No. ML122260684), the Tennessee Valley Authority (the licensee or TVA), submitted a license amendment request (LAR) to revise the Sequoyah Nuclear Plant (SQN), Units 1 and 2, Updated Final Safety Analysis Report (UFSAR) to reflect the results from new hydrologic analysis. These proposed changes are consistent with the latest approved hydrology calculations. The proposed changes in the updated hydrologic analysis include updated input information, and updates to methodology that include the use of the U.S. Army Corps of Engineers Hydrologic Modeling System and River Analysis System software. In order to complete its review of the above documents, the U.S. Nuclear Regulatory Commission (NRC) staff requests additional information originating from our Health Physics and Human Performance Branch (AHPB), and Balance-of-Plant Branch (SBPB):
AHPB Requests for Additional Information (RAls)
- 1.
What, if any, operator actions are being changed, added, or deleted besides those supporting the installation of the spent fuel pit cooling pump enclosure caps, the sand bagging of the diesel generator (DG) building, and the installation of temporary barriers on the earthen embankments of the dams at the Cherokee, Fort Loudoun, Tellico, and Watts Bar Reservoirs?
- 2.
What kind of training is planned for actions supporting the proposed changes to the SQN UFSAR? How often will training on the flood procedure/plan be done?
When will training be complete? For example, will training be complete prior to issuance of the revised UFSAR proposed in this LAR?
- 3.
List the procedures affected by the proposed LAR along with a short summary of the change. When will procedure changes, additions, and deletions associated with the proposed UFSAR changes be completed? For example, will procedures be revised and issued prior to initiation of training?
- 4.
Were any human performance lessons learned from operating experience, sister plants, the Fukushima incident? If yes, describe?
- 5.
Was at least one full complement of required personnel used in the verification and validation of the proposed flood plan? If not, what plans have been made to assure that a representative sample of personnel is included in verification and validation of the flood plan?
Enclosure
- 2
- 6.
During the probable maximum flood (PMF), what communication methods will be likely to fail (fully or partially) and which will still be available for individuals to communicate with the control room, technical support center, and other plant areas? Will site-wide announcements be possible during all stages of the PMF?
- 7.
Describe the changes to the simulator, if any, that are needed to support the proposed license amendment.
- 8.
Describe any credible errors that could affect the pre-staging or the actual placing of sandbags around the DG building entrance?
- a.
Will the placement of the sandbags interfere with operation or corrective maintenance? Where are the sandbags pre-staged? If pre-staged at a distance from the DG building, how will they be moved and finally placed around the building?
- b.
Are the sandbagging actions specified in a controlled procedure? If yes, provide the procedure with markups showing any revisions necessary to support this LAR.
- c.
How much do the sandbags weigh, how many are needed, how many people will be needed, and how long will it take? Have validation walkthroughs been performed?
- d.
Is training required? If yes, how often?
- 9.
Describe any credible errors that could be made when installing the spent fuel pit cooling pump enclosure caps. Are the involved actions described in a controlled procedure? Will training be provided?
- 10.
On page 15 of 39 in Enclosure 1 of the LAR dated August 10, 2012, the licensee states that TVA's climatic monitoring, flood predicting systems and flood control facilities permit early identification of potentially critical flood producing conditions and reliable prediction of floods that may exceed plant grade well in advance of the event. Is this prediction done using a controlled procedure consistent with the assumptions of the current hydrology analysis? What actual margin is associated with the term "well in advance"? Describe in terms of approximate number of minutes, hours, or days.
The licensee states on page 29 of 39 in Enclosure 1 of the LAR: "Flood warnings are issued in real-time by TVA RO [River Operations]." In what form are the flood warnings issued? How does the SON control room receive the warning and how long does it take to get from TVA (RO) to the control room supervisors?
- 12.
On page 30 of 39 of the LAR, the licensee states, "... lower forecast threshold warning flood elevations are used in some situations to assure that the 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> pre-flood transition interval is always available." Who makes this decision, on 11
- 3 what basis? Will the emergency action level notifications move forward in concert with the warning(s)?
- 13.
On page 32 of 39 in Enclosure 1 of the LAR, the assumptions for initial conditions in the flood plan include plants at 100 percent power. Are there any plant modes other than 100 percent power that could complicate planned responses, demand additional staffing, or extend response times? For example, would there be any effect on the flood plan if SQN, Unit 1 was in the middle of refueling and SQN, Unit 2 was at some intermediate power level? Are the timing estimates for Stage I and Stage" actions the same regardless of the age of the core (Le., rapid shutdown will take the same amount of time whether the plant's core is at end-of life or is a fresh full-core refueling)?
- 14.
On page 14 of 39 of the LAR, it is stated that low water levels at the plant intakes could be experienced in as little as 51 hours5.902778e-4 days <br />0.0142 hours <br />8.43254e-5 weeks <br />1.94055e-5 months <br /> if the downstream dam fails during a drought. Is there a plan or procedure in place that addresses the loss of heat sink? What alerts are available to cue the operators that a loss of heat sink is underway? How long after the failure of the dam would operators be aware that a loss of heat sink may be underway?
- 15.
The Hydrologic Basis for Warning System section on page 17 of Enclosure 1 of the LAR discusses Stage I and Stage" and the times associated with each stage. How was the time determined for each stage (10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> for Stage I and 17 hours1.967593e-4 days <br />0.00472 hours <br />2.810847e-5 weeks <br />6.4685e-6 months <br /> for Stage II)? If determined by the walkdown, was a full complement of required personnel involved? Clarify how this integrates with the emergency plan (e.g., whether the emergency plan call-in methods will provide enough people to implement the flood plan(s) in enough time).
- 16.
The licensee states on page 27 of 39 of Enclosure 1 of the LAR, "As a part of TVA ROts flood control responsibilities, forecast and warning procedures have been established that reflect the updated hydrologic analyses." As part of the configuration control process for these procedures, is the SQN site included in the review and approval of technical changes?
- 17.
The "shortest warning time" is discussed in several sections of the application, but not quantified. What were the shortest possible warning times analyzed for Stage I and Stage" warnings? Begin at the time the operators in the SQN control rooms receive the warning.
- 18.
In the UFSAR, Section 2.4.10, paragraph 3, it is stated, "Warning of seismic failure of key upstream dams will be available at the plant approximately 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> before a resulting flood surge would reach plant grade." What is the basis for this statement?
- 19.
If off-site power is lost early in Stage I, what are the effects on Stage I timing, staffing, personnel actions, action sequences, warnings, and emergency action level notifications?
- 4
- 20.
On page 9 of 14 of Enclosure 2 of the LAR, the licensee states, 'The updated DBF [design-basis flood] analysis for SON indicated that some upstream dam earth embankments could be overtopped during the PMF. Four dams were identified as having embankments that could be overtopped during the PMF:
Cherokee; Fort Loudoun; Tellico; and Watts Bar." As a temporary measure, HESCO Concertainer units have been installed at each of the four dams. What organization was responsible for installing the HESCO Concertainers? Were they installed under an NRC-approved quality assurance program or equivalent, using controlled drawings, procedures, and documents? What barriers to human error were used (e.g., pre-job brief, independent verification, self-checking)?
- 21.
On page 9 of 14 of Enclosure 2 of the LAR, the licensee states, "The maintenance of the temporary flood barriers and closure of openings during emergency events is a River Operations (RO) - Asset Owner (AO) responsibility, as defined by Dam Safety procedure RO-SPP-27.0." What is the sequence-of-events regarding the RO's closure of openings during emergency events in relationship to the site flood plan? What alerts the RO to close the openings and how long will it take? What credible errors are associated with the HESCO temporary barriers or their closure during a flood event?
- 22.
Will site personnel need to know the actual flood levels to perform any required actions in the flood plan or shutdown procedures? If yes, how will flood level be determined?
SBPB RAls
- 1.
The revised DBF level at the DG building exceeds the elevation of the DG building floor. As a temporary measure, a berm of sandbags will be constructed around the DG building entrances. The application states that these sandbags are staged on-site.
Describe how the availability of sandbags in sufficient quantity will be ensured when required (Le., inclusion in station procedures, etc.).
- 2.
The LAR states that the licensee will install permanent plant modifications to provide adequate flooding protection with respect to the DBF level for the DG building, by March 31, 2013. This is earlier than the requested review date of this LAR (August 10, 2013), but information on the permanent modification to the DG building is not provided.
Describe the design of these permanent plant modifications and how they will provide adequate flooding protection for the DG building. The response should include any proposed UFSAR text changes reflecting flooding protection of the DG building.
- 3.
The SON UFSAR Section 2.4A.2.1, "Flooding of Structures," states that the DG building has redundant sump pumps to remove minor leakage.
- 5 Do the sump pumps discharge leakage from the DG building at a point higher than the revised DBF level? If not, provide information on how backflow through the discharge piping is prevented.
- 4.
The LAR states that heat removal from the steam generators will be accomplished using the high pressure fire protection system following a Stage II flood warning.
Where are the required components of the high pressure fire protection system located? Is this system protected from the revised DBF levels?
- 5.
The LAR states that the spent fuel pool cooling pump motors platform is located in an enclosure that provides flooding protection up to elevation 724.5 feet. The spent fuel pool cooling pump enclosure caps are required to be installed in order to provide flooding protection to this elevation.
Describe the physical design of the enclosure and how installing the caps will ensure flooding protection up to the 724.5 feet elevation. Will installing the caps impact the performance of the spent fuel pool cooling pumps? With the caps installed, can the spent fuel pool cooling pumps still be aligned for open reactor cooling as described in UFSAR Section 2.4A.2.2, "Fuel Cooling"?
- 6.
The Sequoyah UFSAR flooding protection plan states that the penetrations of the reactor building, DG building, and essential raw cooling water intake station are designed to withstand the static and dynamic forces imposed by the DBF.
Do the penetrations of these structures continue to withstand the forces associated with the revised DBF and prevent leakage? Describe how the penetrations were evaluated for the revised DBF.
January 25, 2013 Mr. Joseph W. Shea Vice President, Nuclear Licensing Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING REVISION OF THE UPDATED FINAL SAFETY ANALYSIS REPORT TO ADOPT A REVISED HYDROLOGIC ANALYSIS (TAC NOS. ME9238 AND ME9239)
Dear Mr. Shea:
By letter dated August 10, 2012, you submitted an application for license amendment to revise the Updated Final Safety Analysis Report to adopt a revised hydrologic analysis for Sequoyah Nuclear Plant, Units 1 and 2 sites. These proposed changes are consistent with the latest approved hydrology calculations. The proposed changes in the updated hydrologic analysis include revised input information, and updates to methodology that include the use of the U.S.
Army Corps of Engineers Hydrologic Modeling System and River Analysis System software.
The U.S. Nuclear Regulatory Commission staff is reviewing the submittal and has determined that additional information is required to complete its evaluation. This request was discussed with Mr. Clyde Mackaman of your staff on January 17, 2013, and it was agreed that a response would be provided within 45 days from the date of this letter.
If you have any questions regarding this matter, I can be reached at 301-415-1564.
Sincerely, IRAJ Siva P. Lingam, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv DISTRIBUTION:
PUBLIC LPL2-2 R/F RidsNrrDorlLpl2-2 RidsNrrPMSequoyah G. Lapinsky, NRR RidsNrrLABClayton RidsOgcMailCenter RidsNrrDorlDpr RidsAcrsAcnw_MailCTR F. Keith, NRR RidsNrrDssSbpb RidsRgn2MailCenter RidsNrrDraAhpb E. Davidson, NRR ADAMS Accession No: ML13018A053
- Transmitted by memo dated
==JI OFFICE NAME LPL2-2/PM SLinqam LPL2-2/LA(IT)
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