ML15112A292
| ML15112A292 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/26/1998 |
| From: | Labarge D NRC (Affiliation Not Assigned) |
| To: | Mccollum W DUKE POWER CO. |
| References | |
| TAC-MA3765, TAC-MA3766, TAC-MA3767, NUDOCS 9810290100 | |
| Download: ML15112A292 (6) | |
Text
October 26, 192 Mr. W. R. McCollum Vice President, Oconee W Duke Energy Corporation P. 0. Box 1439 Seneca, SC 29679
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - USE OF REACTOR BUILDING OVERPRESSURE CREDIT TO ASSURE ADEQUATE NET POSITIVE SUCTION HEAD FOR THE REACTOR BUILDING SPRAY PUMPS - OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 (TAC NOS. MA3765, MA3766, AND MA3767)
Dear Mr. McCollum:
By letter dated October 2, 1998, Duke Energy Corporation (DEC) requested the staffs review and approval of the use of reactor building overpressure credit in the calculation of the available net positive suction head (NPSH) for the reactor building spray pumps for a limited period of time during the post-accident recirculation phase at Oconee Nuclear Power Station, Units 1, 2, and 3. DEC concluded that the proposed modification is an unreviewed safety question.
The staff has reviewed your request and determined that additional information is needed. The questions are contained in the enclosure and concentrate on the NPSH requirements for the reactor building spray pumps and the use of high temperature correction factors. Due to the potential safety concerns and the relative importance of understanding the basis of the Oconee calculations and operability determination, please respond to this request by November 20, 1998, as discussed with Mr. Ed Burchfield of your staff.
Sincerely, ORIGINAL SIGNED BY:
David E. LaBarge, Senior Project Manager 0 98 Project Directorate 11-2 98129100 981026 PDR ADOCK 05000269 Division of Reactor Projects - 1/11 P
PDR Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
Request for Additional Information cc w/encl: See next page Distribution:
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 26, 1998 Mr. W. R. McCollum Vice President, Oconee Site Duke Energy Corporation P. 0. Box 1439 Seneca, SC 29679
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - USE OF REACTOR BUILDING OVERPRESSURE CREDIT TO ASSURE ADEQUATE NET POSITIVE SUCTION HEAD FOR THE REACTOR BUILDING SPRAY PUMPS - OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 (TAC NOS. MA3765, MA3766, AND MA3767)
Dear Mr. McCollum:
By letter dated October 2, 1998, Duke Energy Corporation (DEC) requested the staffs review and approval of the use of reactor building overpressure credit in the calculation of the available net positive suction head (NPSH) for the reactor building spray pumps for a limited period of time during the post-accident recirculation phase at Oconee Nuclear Power Station, Units 1, 2, and 3. DEC concluded that the proposed modification is an unreviewed safety question.
The staff has reviewed your request and determined that additional information is needed. The questions are contained in the enclosure and concentrate on the NPSH requirements for the reactor building spray pumps and the use of high temperature correction factors. Due to the potential safety concerns and the relative importance of understanding the basis of the Oconee calculations and operability determination, please respond to this request by November 20, 1998, as discussed with Mr. Ed Burchfield of your staff.
Sincerely, David E. LaBarge, Senior Project Manager Project Directorate 11-2 Division of Reactor Projects - III Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
Request for Additional Information cc w/encl: See next page
Oconee Nuclear Station cc:
Mr. Paul R. Newton Mr. J. E. Burchfield Legal Department (PBO5E)
Compliance Manager Duke Energy Corporation Duke Energy Corporation 422 South Church Street Oconee Nuclear Site Charlotte, North Carolina 28201-1006 P. 0. Box 1439 Seneca, South Carolina 29679 J. Michael McGarry, III, Esquire Winston and Strawn Ms. Karen E. Long 1400 L Street, NW.
Assistant Attorney General Washington, DC 20005 North Carolina Department of Justice Mr. Rick N. Edwards P. 0. Box 629 Framatome Technologies Raleigh, North Carolina 27602 Suite 525 1700 Rockville Pike L. A. Keller Rockville, Maryland 20852-1631 Manager - Nuclear Regulatory Licensing Manager, LIS Duke Energy Corporation NUS Corporation 526 South Church Street 2650 McCormick Drive, 3rd Floor Charlotte, North Carolina 28201-1006 Clearwater, Florida 34619-1035 Mr. Richard M. Fry, Director Senior Resident Inspector Division of Radiation Protection U. S. Nuclear Regulatory North Carolina Department of Commission Environment, Health, and 7812B Rochester Highway Natural Resources Seneca, South Carolina 29672 3825 Barrett Drive Raleigh, North Carolina 27609-7721 Regional Administrator, Region II U. S. Nuclear Regulatory Commission Mr. Steven P. Shaver Atlanta Federal Center Senior Sales Engineer 61 Forsyth Street, S.W., Suite 23T85 Westinghouse Electric Company Atlanta, Georgia 30303 5929 Carnegie Blvd.
Suite 500 Virgil R. Autry, Director Charlotte, North Carolina 28209 Division of Radioactive Waste Management Bureau of Land and Waste Management Department of Health and Environmental Control 2600 Bull Street Columbia, South Carolina 29201-1708 County Supervisor of Oconee County Walhalla, South Carolina 29621
e*
Request for Additional Information Oconee Nuclear Power Station, Units 1. 2 and 3 By letter dated October 2, 1998, Duke Energy Corporation (DEC) requested the staffs review and approval of the use of reactor building overpressure credit in the calculation of the available net positive suction head (NPSH) for the reactor building spray (RBS) pumps for a limited period of time during the post-accident recirculation phase at Oconee Nuclear Power Station, Units 1, 2 and 3. DEC concluded that the proposed modification is an unreviewed safety question. The staff requests that Duke respond to the following:
- 1. Provide the NPSH calculations of record for the RBS and low pressure injection (LPI) pumps for both the injection and recirculation phases. Include the supporting documentation as necessary. According the license amendment request, DEC is currently performing additional analyses to determine if additional margin can be established regarding the RBS NPSH requirements. Please provide any applicable update to the requested NPSH calculations as they become available.
- 2. Page 12 of the October 2, 1998, submittal states that the RBS NPSH analysis utilizes design inputs that include NPSH requirements provided by the pump manufacturer and adjusted by application of high temperature correction factors. Provide the source of the high temperature correction factors (e.g., Hydraulics Institute) and explain why it is acceptable to use them in this analysis. The use of hot fluid correction factors was discussed in the background section of Generic Letter 97-04, "Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps."
- 3. If the high temperature correction factors are from the Hydraulic Institute Standard, explain how the limitations and precautions are included in the NPSH calculation. The Hydraulic Institute Standards (currently American National Standard for Centrifugal Pumps) provide limitations and precautions for use of the NPSH-required temperature reduction, including considerations of entrained air or other gases present in the liquid and consideration of the susceptibility of the suction system to transient changes in temperature and absolute pressure.
- 4. Page 6 of your October 2, 1998, submittal refers to additional data provided by the pump vendor to support the NPSH analyses for the LPI and RBS pumps. Discuss the additional data received by the vendor and explain how it is being relied upon in the NPSH analysis.
- 5. Page 12 of your October 2, 1998, submittal states that a single failure of one low pressure injection train, RBS train, and one reactor building cooling unit was assumed. However, Section 15.14.3.3.6, ECCS Performance and Single Failure Assumption, of the Oconee Final Safety Analysis Report states: "historically, the worst single failure for a LOCA [loss-of coolant accident] is the loss of one bus of emergency power which results in the loss of one train of HPI [high pressure injection] and one train of LPI. The failure of transformer CT-4 Enclosure
-2 has been identified as a more limiting single failure for the large break LOCA. The failure of transformer CT-4 results in a longer delay until delivery of ECCS [emergency core cooling system] fluid to the reactor coolant system (RCS). However, two ECCS trains are available with this single failure. Reference 33 demonstrates that having two ECCS trains injection at a later time is more limiting than having one ECCS train injecting at an earlier time." Since a large break LOCA is limiting for NPSH considerations, explain why this new single failure is not more limiting than one being assumed in the NPSH analysis.
- 6. Provide a graph that depicts the NPSH required in pounds per square inch for the RBS and LPI pumps versus time and the calculated NPSH available versus time. A sample of the type of graph that is requested is provided for your convenience.
Attachment:
Sample Graph
NPSH Availability for RHR and Core Spray System Pc (psia) 5% Leakage Pc (psia) @ 0.5% Leakage Pc Req'd
-S-Pool Temp ("F) 22 170 2 0 160 I8 50 916 IL-40 14 13o 12 120 L
10 110 100 1000 10000 100000 1000000 Time After Accident (seconds)
Attachment