ML20216H545
| ML20216H545 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 04/09/1998 |
| From: | Hammer M NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-96-003, IEB-96-3, NUDOCS 9804210186 | |
| Download: ML20216H545 (3) | |
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Northem States Power Company Monticello Nuclear Generating Plant 2807 West Hwy 75 MonNcello, Minnesota 55362 9637 April 9,1998 j
US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 l
NSP Update on Status of Debris Loading for ECCS Suction Strainers Ref.1 Letter from Tae Kim, NRC, to Roger O. Anderson, NSP, "Monticello Nuclear Generating Plant -Issuance of Amendment Re: Updated Analysis of DBA Containment Temperature and Pressure Response and Reliance on Containment Pressure to Compensate for Potential Deficiency in NPSH for ECCS Pumos During DBA (TAC No. M97781)," July 25, l
1997 1
Ref. 2 Letter from M. F. Hammer, NSP, to NRC Document Control Desk, " Revision 1 to License Amendment Request Dated July 26,1996 Supporting the Monticello Nuclear Generating j
Plant Power Rerate Program," December 4,1997 Prior to startup from the 1997 suction strainer outage, NSP completed a calculation that demonstrated adequate NPSH using conservative values for containment response derived l
from the power rerate analyses. The original design basis assumptions for strainer plugging were used in this calculation. The strainer head loss assumption was intended to bound the additional head loss that may occur due to debris loading. By section 3.8 of Ref.1, the staff accepted this interim approach to the concerns of NRC Bulletin IEB 96-03, " Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors."
i By letter dated December 4,1997 (Ref. 2), NSP documented a commitment to complete a NPSH calculation for the ECCS suction strainer debris by a specified date. Because of the unresolved industry-wide issues concerning debris loading, NSP subsequent!y proposed and the staff agreed to allow NSP to delay its final response on debris loading until these generic issues have been resolved.
NSP conducted debris testing of a full scale mockup of the new MNGP strainer at the EPRI test facility in November 1997. Preliminary results indicate that the strainer head loss assumption for debris loading is reasonable. An industry effort is underway to define the character and extent of the debris loading for suction strainers subject to staff approval. NSP is closely following
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these efforts and will submit a response when the above issues have been resolved.
i 9804210186 980409 PDR ADOCK 05000263 P
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l Please contact Joel Beres, Monticello Licensing, at (612) 295-1436 if additional information is required.
- Q Michael F. Hammer i
Plant Manager i
Monticello Nuclear Generating Plant l
i c:
Regional Administrator-lil, NRC l
NRR Project Manager, NRC Sr. Resident inspector, NRC State of Minnesota, Attn: Kris Sanda I
J. Silberg, Esq.
Attachment NSP Affidavit to the Nuclear Regulatory Commission l
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UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263 NSP Update on Status of Debris Loading for ECCS Suction Strainers Northern States Power Company, a Minnesota corporation, by letter dated April 9,1998 provides a status update of its review for debris loading of ECCS suction strainers at Monticello. This letter contains no restricted o other defense information.
i NORTHERN STATES POWER COMPANY By h
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Mich'aeiF. 4ammer 4
Plant Manager Monticello Nuclear Generating Plant On this day of koc'd (MB before me a notary public in ano for said County, personally hppeared Michael F. Hammer, Plant Manager, Monticello Nuclear Generating Plant, and being first duly sworn acknowledged that he is authorized to execute this document on behalf of Northetn States Power Company, and that to the best of his knowledge, information, and belief the statements made in it are true.
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