ML20203G494

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Forwards Rev 0 to NSPNAD-8606P Prairie Island Units 1 & 2 Auxiliary Feedwater Sys Reliability Study. Evaluation in NUREG-0611 Should Not Be Used in Future Actions Re Auxiliary Feedwater Sys Reliability
ML20203G494
Person / Time
Site: Prairie Island  Xcel Energy icon.png
Issue date: 04/24/1986
From: Musolf D
NORTHERN STATES POWER CO.
To:
Office of Nuclear Reactor Regulation
Shared Package
ML20203G501 List:
References
RTR-NUREG-0611, RTR-NUREG-611 TAC-61519, TAC-61520, NUDOCS 8604290133
Download: ML20203G494 (2)


Text

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Northem States Power Company 414 Niconet Mall ,

Minnespohs. Minnesota 55401 Telephone (612) 330-5500 April 24, 1986 Director Office of Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT DOCKET NOS- 50-282 LICENSE NOS. DPR-42 50-306 DPR-60 Auxiliary Feedwater System Reliability Study On November 6, 1986 representatives of Northern States Power Company met with the NRC Staff to discuss the reliability of the auxiliary feedwater system at the Prairie Island Nuclear Generating Plant. At this meeting we presented the NRC Staff with information related to the design of the auxilia-ry feedwater system at Prairie Island and discussed plans for a reliability study to be performed to determine if the Prairie Island design is deficient in any way. This analy-sis has now been completed. The purpose of this letter is to transmit the analysis for the information of the NRC Staff.

On the basis of an analysis presented in NUREG-0611, " Generic Evaluation of Feedwater Transients and Small Break Loss-of-Coolant Accidents in Westinghouse-Designed Operating Plants," January, 1980, Prairie Island appeared to have a lower than average auxiliary feedwater system reliability.

This six-year old report has been used by members of the NRC Staff in public discussions of planned regulatory actions to improve auxiliary feedwater system reliability in the wake of the June, 1982 Davis-Besse event. The analysis presented in NUREG-0611 does not include improvements made in the Prairie Island auxiliary feedwater system in response to NUREG-0737.

An noted in the attached report, " Prairie Island Units 1 and 2 Auxiliary Feedwater System Reliability Study," NSPNAD-86906P, April, 1986, an analysis of the reliability of the Prairie Island auxiliary feedwater system which incluoes modifications made subsequent to NUREG-0611 shows a system reliability that compares very favorably with other facili-ties and lies well within the NRC's range of acceptability.

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Northem States Power Company Director of NRR April 24, 1986 Page 2 As part of this analysis Northern States Power Company sought to determine if there were any changes in system design, maintenance, or operation which could significantly improve system reliability. A number of such changes were identified. These are described in Section 5.5 of the  !

attached report. These recommendations are currently being I reviewed by the plant technical staff for implementation. .

Completion of these modifications could significantly in-prove the already high reliability of the Prairie Island design. We will inform the NRC Prairie Island licensing project manager, Mr Dominic Dilanni, of our specific plans and schedule for implementing changes.

We request that the evaluation presented in NUREG-0611 not be used by the NRC Staff in future actions related to Prairie Island auxiliary feedwater system reliability and that the attached analysis be made available to the Staff for their consideration.

Please contact us if you have any questions related to our reliability study .or if additional information is required to resolve this matter.

D&w. -

David Musolf Manager Nuclear Support Services c: NRR Project Manager, NRC Resident Inspector, NRC Regional Administratcr. Region III, NRC G Charnoff Attachment

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