ML090540508
| ML090540508 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 03/03/2009 |
| From: | Lyon C Plant Licensing Branch IV |
| To: | Minahan S Nebraska Public Power District (NPPD) |
| Lyon C Fred, NRR/DORL/LPL4, 301-415-2296 | |
| References | |
| TAC MD9921 | |
| Download: ML090540508 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 r'1arch 3, 2009 Mr. Stewart B. Minahan Vice President-Nuclear and CNO Nebraska Public Power District 72676 648A Avenue Brownville, NE 68321
SUBJECT:
COOPER NUCLEAR STATION - REQUEST FOR ADDITIONAL INFORMATION RE: ALTERNATIVE SOURCE TERM (TAC NO. MD9921)
Dear Mr. Minahan:
By application dated October 13, 2008, to the U.S. Nuclear Regulatory Commission (NRC)
(Agencywide Documents Access and Management System Accession No. ML082910760),
Nebraska Public Power District (the licensee) requested NRC staff approval of an amendment to the Cooper Nuclear Station facility operating license and technical specifications to adopt the Alternative Source Term for use in calculating the Loss-of-Coolant Accident dose consequences.
The NRC staff reviewed the information provided in your application and determined that additional information is required in order to complete its review. Please provide a response to the enclosed questions by April 10, 2009.
The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for NRC staff review and contribute toward the NRC's goal of efficient and effective use of NRC staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-2296.
Sincerely, Carl F. Lyon, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-298
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION ALTERNATIVE SOURCE TERM COOPER NUCLEAR STATION DOCKET NO. 50-298 Reactor Systems Branch Request for Additional Information (RAI) 1 If Cooper Nuclear Station (CNS) intends to take credit of the standby liquid control (SLC) system for the purpose of controlling pH level in the suppression pool (SP) water by injecting boron solution into the lower plenum of the reactor vessel during the long-term cooling phase of a loss-of-coolant accident (LOCA), concerns regarding the possibility of boron precipitation in the CNS core should be addressed. The U.S. Nuclear Regulatory Commission staff understands that when the SLC system is initiated, boron solution injected from the SLC system will mix with the coolant from the residual heat removal (RHR) system in the vessel lower plenum, and a portion of the mixture will then flow into the core where it will undergo sustained boll-off in order to remove the decay heat. The remainder of the boron solution can overflow through the jet pump and reach the SP. During this process, the core should remain covered to two-thirds of its height, while core boil-off removes the decay heat. The staff requests the licensee to provide following additional information:
- a.
Describe the flow path of boron solution mixture after initiation of the SLC system following a LOCA, including the path through the core.
- b.
Justify how sustained and continuous boil-off of water mixed with the boron solution inside the core will not cause boron concentration to increase with time, and ultimately, precipitate in the core during the RHR cooling mode of a LOCA.
- c.
Describe what measures are taken to monitor boron concentration in the core after the SLC system is initiated following a LOCA, and how to prevent potential boron precipitation in the core due to sustained boil-off in the core.
Mechanical and Civil Engineering Branch RAI 1 Page 1.183-8 of Regulatory Guide (RG) 1.183 (Section 1.3.2, "Re-Analysis Guidance) denotes the responsibility of licensees to evaluate the nonradiological impacts of an alternative source term implementation and the impacts of any associated plant modifications. In Section 4.1.7 of your October 13, 2008, submittal, you indicated that various portions of the heating, ventilation, and air conditioning (HVAC) systems for the Control Room (the Control Room air conditioning system and the Control Room emergency filtration system) would be credited in calculating the LOCA dose consequences. Please discuss the methodology used for the seismic qualification of the Control Room HVAC systems.
Enclosure
March 3, 2009 Mr. Stewart B. Minahan Vice President-Nuclear and CNO Nebraska Public Power District 72676 648A Avenue Brownville, NE 68321
SUBJECT:
COOPER NUCLEAR STATION - REQUEST FOR ADDITIONAL INFORMATION RE: ALTERNATIVE SOURCE TERM (TAC NO. MD9921)
Dear Mr. Minahan:
By application dated October 13, 2008, to the U.S. Nuclear Regulatory Commission (NRC)
(Agencywide Documents Access and Management System Accession No. ML082910760),
Nebraska Public Power District (the licensee) requested NRC staff approval of an amendment to the Cooper Nuclear Station facility operating license and technical specifications to adopt the Alternative Source Term for use in calculating the Loss-of-Coolant Accident dose consequences.
The NRC staff reviewed the information provided in your application and determined that additional information is required in order to complete its review. Please provide a response to the enclosed questions by April 10, 2009.
The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for NRC staff review and contribute toward the NRC's goal of efficient and effective use of NRC staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-2296.
Sincerely,
/RN Carl F. Lyon, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-298
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv DISTRIBUTION:
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MMarkley FLyon DATE 3/3/09 2/25/09 2/12/09 2/20/09 3/3/09 3/3/09 ADAMS Accession No " ML090540508 OFFICIAL RECORD COpy