ML20249B464

Forwards Response to 980519 RAI Re GL 97-04, Assurance of Sufficient NPSH for ECC & Containment Heat Removal Pumps. One New Commitment Made by Licensee,Identified in Bold Italics

ML20249B464
Person / Time
Site:	Prairie Island
Issue date:	06/15/1998
From:	Richard Anderson NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-97-04, GL-97-4, NUDOCS 9806230179
Download: ML20249B464 (4)

Text

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Northem states Power Company 1717 Wakonade Dr. E.

Welch, MN 55089 Telephone 612-388-1121 June 15,1998 i

10 CFR Part 50.54(f)

Generic Letter 97-04 i

U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Response to May 19,1998, Request for Additional Information on i

Responses to Generic Letter 97-04 Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps The attached information is being provided in response to an NRC staff request dated May 19,1998, for additional information related to our January 5,1998, response to Generic Letter 97-04. In this submittal we have made one new NRC commitment identified in the attachment in bold italics. If you have any questions related to this response, please contact John Stanton at 612-388-1121.

I Ro er O Anderson Director l

Nuclear Energy Engineering 9006230179 990615 I

PDR ADOCK 05000282 P

PDR v d

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June 15,1998

,-' Page 2 Attachments:

fridavit'

-: Attachment, Response to Request for Additional Information on GL 97-04

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Regional Administrator-Ill, NRC NRR Project Manager, NRC Senior Resident inspector, NRC l

Kris Sanda, State of Minnesota J E Silberg ~

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UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT DOCKET Nos. 50-282 50-306 GENERIC LETTER 97-04 I

Response to May 19,1998, Request for Additional Information on i

Responses to Generic Letter 97-04 Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps Northern States Power Company, a Minnesota corporation, with this letter is providing a response to the May 19,1998, NRC request for addition information on responses to Generic Letter 97-04. This letter and its attachments contain no l

restricted or other defense information.

NORTHE STATES POWER COMPANY By twsd R'ogerD Anderson h

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15

• dayof due RW On this before me a notary public in and for said County, personally appeared, Roger O Anderson, Director, Nuclear Energy Engineering, and being first duly sworn acknowledged that he is authorized to execute this document on behalf of Northern States Power Company, that he knows the contents thereof, and that to the best of his knowledge, information, and belief the statements made in it are true and that it is not interposed for delay.

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USNRC NORTHERN STATES POWER COMPANY June 15,1998

• Page1 Attachment Response to May 19,1998, Request for Additionalinformation on Responses to Generic Letter 97-04 Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps Question 1:

in response to question 1, it was stated that a documented analysis to support the results reported in the final safety analysis (FSAR) could not be found. However, a new calculation was prepared and under review at the time of submittal. Has the new calculation been approved for use at Prairie Island?

Response

Yes, the new calculation was approved on February 24,1998.

Question 2:

Is the new analysis considered to be your current licensing basis? Will the FSAR be revised to match the results of the new analysis?

Response

Yes, the calculation is now the analysis of record and the results will be included in a revision of the updated safety analysis report (USAR) prior to the end of 1998.

Question 3:

What was the maximum sump temperature assumed in the NPSH analyses?

Response

The methodology for the calculation ensures that the maximum postulated sump liquid temperature is bounded. As detailed in the January 5,1998 submittal, the methodology for the analysis is to assume the containment pressure is equal to the vapor pressure of the sump liquid. Using this methodology, the first two terms in the NPSH. calculation (H and Hyp,)

3 are equal and cancel each other. This is valid regardless of the sump liquid temperature. This methodology is consistent with the licensing basis for the plant as described in the USAR.

For determining the liquid height on the containment floor, during the time period when transfer to recirculation operation would be performed, the liquid temperature is assumed to be 200*F.

The sump liquid temperature in the USAR is predicted to be higher than 200*F during this time period. Thus, this is a conservative temperature for determining liquid height during the immediate time periods following the accident; that is, when the liquids spilled to containment are at a minimum. An additional part of the analysis determined the sump liquid height during i

the long term based on a sump liquid temperature of 60 F.

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