ML20214C826

Responds to IE Bulletin 86-003, Potential Failure of Multiple ECCS Pumps Due to Single Failure.... Plant Does Not Have Single Failure Vulnerability in Min Flow Recirculation Lines of Any ECCS Pump

ML20214C826
Person / Time
Site:	Monticello
Issue date:	11/12/1986
From:	Larson C NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-86-003, IEB-86-3, NUDOCS 8611210253
Download: ML20214C826 (3)

Text

V tjtf/ pmB Northern States Power Company 414 Nico!!et Matt Minneapolis, Minnesota 55401 Telephone (612) 330 5500 November 12, 1986 Mr James Keppler, Director Region III, Office of Inspection and Enforcement U S Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, T T. 60137 MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Response to IE Compliance Bulletin 86-03 IE Compliance Bulletin 86-03, " Potential Failure of Multiple ECCS Pumps Due to Single Failure of Air-Operated Valve in Minimum Flow Recirculation Line" was issued for action to all plants. The action required is to determine whether or not there is a vulnerability to a single failure in the minimum flow recirculation line of any ECCS pump that could cause a failure of more than one ECCS train. The following is provided in response to IE Compliance Bulletin 86-03.

The vulnerability of the RHR System to a single failure of the minimum flow logic was addressed in response to IE Compliance Bulletin 86-01, " Minimum Flow Logic Problems That Could Disable RHR Pumps", and, as stated in IE Compliance Bulletin 86-03, this aspect is not required to be addressed again. The vulnerability to a single failure of the minimum flow paths was determined by reviewing the piping diagrams. Each train of RHR has its own separate recirculation header.

The vulnerability of the Core Spray System to a single failure of the minimum flow paths was determined by reviewing the piping diagrams. The minimum flow protection for the Core Spray pumps is provided by an orificed line for each pump which has a lormally locked open, manually operated, isolation valve.

There is no minimum flow control vr.1ve that is required to open to provide protection to the core Spray Pumps in the event the injection valves do not open. The recirculation headers for each Core Spray pump are separate and have no common lines.

There are common recirculation paths for more than one ECCS System (i.e., RHR Train A, Core Spray Train A and HPCI minimum flow lines discharge to a common header), but there are no valves in any of these common headers.

8611210253 861112 PDR ADOCK 05000263 I

G PDR g1 7 19861

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. Mr Jamso K:ppler, Reg III Novsmber 12, 1986

. Page 2 Northern States Power Company Based on the above information, it can be concluded that no single failure in the minimum flow recirculation lines of any ECCS pumps could cause a failure of more than one ECCS train. Therefore, the Monticello Nuclear Generating Plant does not have the single failure vulnerability described in IE Compliance Bulletin 86-03.

N C E Larson Vice President Nuclear Generation CEL/DMM/ dab c: NRR Project Manager, NRC Resident Inspector, NRC G Charnoff NRC Document Control Desk

UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 RESPONSE TO IE COMPLIANCE BULLETIN 86-03 Northern States Power Company, a Minnesota corporation, by this letter dated November 12, 1986 hereby submits the response to IE Compliance Bulletin 86-03 for the Monticello Nuclear Generating Plant.

This letter contains no restricted or other defense information.

NORTHERN STATES POWER COMPANY By j  %

C E Larso

• Vice Presiden , Nuclear Generation On this / j d day of m = I - , /9 before me a notary public in and for said County, personally appeared C E L' arson, Vice President, Nuclear Generation, 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 state-ments made in it are true and that it is not interposed for delay.

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f JUOfLRUPP95 NOTARY PUOUC-tmM3014 ANDRA COUNTY Ny Commemon bpwes Sept 28,INI

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