ML062430342
| ML062430342 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 09/12/2006 |
| From: | Pickett D V NRC/NRR/ADRO/DORL/LPLII-2 |
| To: | Singer K W Tennessee Valley Authority |
| Pickett D V, NRR/DORL, 415-1364 | |
| References | |
| TAC MD1460 nrr-088 | |
| Download: ML062430342 (5) | |
Text
September 12, 2006Mr. Karl W. SingerChief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
WATTS BAR NUCLEAR PLANT, UNIT 1 - REQUEST FOR ADDITIONALINFORMATION REGARDING TECHNICAL SPECIFICATION CHANGEREQUEST FOR ULTIMATE HEAT SINK TEMPERATURE (TAC NO. MD1460)
Dear Mr. Singer:
By letter dated May 8, 2006, the Tennessee Valley Authority (TVA, the licensee) submitted aproposed license amendment (WBN-TS-06-09) that would revise Technical Specification 3.7.9.1, "Ultimate Heat Sink Temperature," that would increase the maximumessential raw cooling water temperature limit from 85 degrees Fahrenheit (F) to 88 F inaccordance with Title 10 Code of Federal Regulations (10 CFR) 50.90.In order for the staff to complete its review of the information provided by the licensee, werequest that TVA provide responses to the enclosed request for additional information (RAI).
Based on discussions with your staff, we understand that you plan to respond to the enclosed RAI within 60 days of receipt of this letter. If you have any questions about this material, please contact me at (301) 415-1364.Sincerely, /RA/Douglas V. Pickett, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-390
Enclosure:
Request for Additional Informationcc: See next page
ML062430342NRR-088OFFICELPL2-2LPL2-2/PMLPL2-2/LASBPB/BCLPL2-2/BCNAMEJPaigeDPickettRSolaJSegalaJDixon-Herrity DATE9/11/069/11/069/8/069/12/069/12/06 Mr. K. W. SingerTennessee Valley Authority WATTS BAR NUCLEAR PLANT cc:Mr. Ashok S. Bhatnagar, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Larry S. Bryant, Vice PresidentNuclear Engineering & Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801Mr. Robert J. Beecken, Vice PresidentNuclear Support Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael D. SkaggsSite Vice President Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381General CounselTennessee Valley Authority ET 11A 400 West Summit Hill DriveKnoxville, TN 37902Mr. John C. Fornicola, ManagerNuclear Assurance and Licensing Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801Ms. Ann P. Harris341 Swing Loop Road Rockwood, Tennessee 37854Mr. Glenn W. Morris, Manager Corporate Nuclear Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801Mr. Paul L. Pace, ManagerLicensing and Industry Affairs Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381Mr. Jay Laughlin, Plant ManagerWatts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381Senior Resident InspectorWatts Bar Nuclear Plant U.S. Nuclear Regulatory Commission 1260 Nuclear Plant Road Spring City, TN 37381County Executive 375 Church Street Suite 215 Dayton, TN 37321County Mayor P. O. Box 156 Decatur, TN 37322Mr. Lawrence E. Nanney, DirectorDivision of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 EnclosureREQUEST FOR ADDITIONAL INFORMATIONWATTS BAR NUCLEAR PLANT, UNIT 1 TECHNICAL SPECIFICATION CHANGE REQUEST FOR ULTIMATE HEAT SINK TEMPERATUREDOCKET NO. 50-3901.In Page 5, Tennessee Valley Authority (TVA) states: "The conclusion of the review is that there is sufficient justification to increase the UHS[ultimate heat sink] upper temperature allowable limit from 85 F to 88 F. Operationalprocedure guidelines will be enhanced, as required, in order to implement this limit."Provide/describe the specific operational procedure guidelines, as required, in order toimplement this proposed limit of 88 F. 2.In Page 13, TVA states that the increased UHS temperature is justified, in part, bymargins in the essential raw cooling water (ERCW) flow rates that were established for each of the affected components during the pre-operational testing program. Provide detailed discussion to explain how the existing flow margins have been demonstrated to still be valid; how much of the existing margin will be used in the revised UHS analysisand how much margin will remain; how much of the remaining margin is needed toaccount for tube pluggi ng, system fouling, pump degradation, measurement uncertainty,etc.; and how technical specification surveillance requirements will ensure that therequired flow margins are maintained over time for all of the affected components.3.General Design Criteria (GDC) 44, "Cooling Water," requires that a system to transferheat from structures, systems, and components important to safety, to an ultimate heatsink shall be provided. The system safety function shall be to transfer the combinedheat load of these structures, systems, and components under normal, operating andaccident conditions. Also, Standard Review Plan (SRP) 9.1.3, "Spent Fuel Pool Cooling And CleanupSystem," specifies that continuous fuel cooling be provided during normal, abnormal, and accident conditions. With regard to TVA's evaluation of the effects on the spent fuel pool (SFP) coolingsystem resulting from the proposed increase in the UHS temperature, providedetailed/complete discussions of:*the SFP cooling licensing basis (e.g., maximum heat load, temperature, time toboil, etc.) along with how the existing licensing basis will continue to be satisfiedat the increased UHS temperature limit; and*how the above cited GDC requirement and SRP criteria will conti nue to besatisfied at the increased UHS temperature limit. Of particular interest is the proposed action to terminate SFP cooling for up to 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />, and to what extent isthis consistent with the plant licensing basis.4.TVA determined that the emergency diesel generator (EDG) jacket water heatexchangers were marginal at the higher UHS temperature and in order to resolve this problem, the heat exchanger cleaning frequency and timing will be changed to annually(instead of during each refueling outage) during the spring (prior to experiencing the hotter summer temperatures). Provide a detailed discussion to explain how the adequacy of this approach will be validated to assure acceptable EDG performanceduring those periods when the UHS temperature may be as high as 88 F and heatexchanger fouling is at maximum.5.The following notes in Table 2 of the submittal attachment (Page 26) credit higher"current" cooling water flow rates: 2, 3, 5, 6, 7, 9 and 11. Provide a detailed discussionto explain why the current flow rates constitute the most limiting condition consistent with licensing basis assumptions.6.Note 7 in Table 2 of the submittal attachment (Page 26) indicates that actual heat loadswere used as a basis to reduce the amount of heat that is required to be rejected.
Provide a detailed discussion to explain why this is a valid approach consistent with the plant licensing basis with respect to the worst case conditions that must be assumed.7.Note 9 in Table 2 of the the submittal attachment (Page 26 & 27) indicates thatincreased ERCW flow rates are credited, whereas the discussion on Page 21 indicates that increased flow rates were not credited for the EDG jacket water heat exchanger.
Please provide clarification for the above discrepancy. Also, provide a detailed discussion to explain how the engineering judgement was validated.8.TVA indicated that the Tennessee River system is capable of providing water beyondthe 30 days (up to one year without any rainfall) as stated in the Updated Final Safety Analysis Report (Page 28). Provide a detailed discussion to explain why this capabilityis not able to maintain the UHS below the current 85 F temperature limit.9.TVA indicated that since ERCW flow margins above the existing flow requirements wereutilized in validating acceptable performance at the higher ERCW temperature, specificevaluations will be performed prior to unit operation above 85 F. The performance ofthese specific evaluations will validate any margin based inputs utilized in the originalanalyses that determined acceptable performance could be achieved at the higherERCW temperature. As indicated in the above item 2, validation of the available flowmargins that are being credited is requested in support of the staff's review of the proposed change. Furthermore, provide additional discussion detailing specifically howthese evaluations will be performed to assure conservative results consistent with licensing basis assumptions.