05000266/LER-1988-008, Informs That Mod to LER 88-008-00 Would Provide Redundant Feedwater Termination in Event of Main Steam Line Break Inside Containment.If Mod Not Completed on Unit 2 During Fall Outage,Mod Will Be Delayed Until Fall 1990 Outage

Informs That Mod to LER 88-008-00 Would Provide Redundant Feedwater Termination in Event of Main Steam Line Break Inside Containment.If Mod Not Completed on Unit 2 During Fall Outage,Mod Will Be Delayed Until Fall 1990 Outage

ML20247N688
Person / Time
Site:	Point Beach
Issue date:	09/20/1989
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Swenson W NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
CON-NRC-89-111 VPNPD-89-498, NUDOCS 8909260274
Download: ML20247N688 (2)

LER-2088-008, Informs That Mod to LER 88-008-00 Would Provide Redundant Feedwater Termination in Event of Main Steam Line Break Inside Containment.If Mod Not Completed on Unit 2 During Fall Outage,Mod Will Be Delayed Until Fall 1990 Outage

Event date:
Report date:
2662088008R00 - NRC Website

text

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-  : Wisconsin Elecinc f POWER COMPANY t

231 w Mchigan, no. Box 2046. Mitwoukee. wi 53201 (414) 221-2345

VPNPD-89-4 98 NRC 111 September 20, 1989 Document Control Desk U.S. NUCLEAR REGULATORY COMMISSION Mail Station F1-137 Washington, D.C. 20555 Attention

Mr. Warren Swenson, Project Manager Project Directorate III-3 Gentlemen:

DOCKET NOS. 50-266 AND 50-301 MAIN STEAM LINE BREAK WITH CONTINUED FEEDWATER ALDITION PBNP UNITS 1 & 2 Licensee Event Report (LER) 88-008-00 for Point Beach Nuclear Plant, Unit 1 discussed the discovery of a design inadequacy involving the single failure of a main feedwater regulating valve to shut. The postulated scenario discussed in the LER could result in the continued addition of'feedwater to the steam generators during a main steam line break (MSLB) accident inside containment while the feedwater pump discharge valves were cycling shut. This would result in exceeding the containment design pressure. Although the consequences of such a scenario are bounded by other analyzed accidents, we proposed modifications to provide redundant feedwater termination in the event of a MSLB inside containment.

The modification discussed under the heading of long term corrective action in the LER consists of hardware and wiring changes to accomplish automatic closure of the existing heater drain tank discharge valves and automatic tripping of the condensate pump motors on a high containment pressure safety injection signal. Our current design is to trip the heater drain tank pumps instead of the discharge valves on a containment HI signal matrix separate from that used for safety injection. Although our detailed cesign of these modifications has not prcgressed as we had originally planned, we are continuing to make plans and preparations to install these  ;

modifications on Point Beach Unit 2 during the fall 1989 ,

refueling outage. However, until we begin the actual wiring {

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Page 2 modifications within the existing instrumentation and electrical power mapply racks, we cannot be certain that these modifications can be completed this outage without the need for additional design activities. Accordingly, this letter is to I advise you that our schedule for completion of the modification discussed in LER 88-008-00 may be delayed for Point Beach Unit 2.

If the modification is not completed on Unit 2 during this fall outage, it will be delayed until the 1990 fall outage. We will inform you and provide a revised completion schedule should this occur. The design and work necessary to complete the Unit 1 work will be similar to the Unit 2 effort and we anticipate no problems in satisfying our spring 1990 commitment for completing this work on Point Beach Unit 1.

Please contact us if you have any questions concerning our activities in this regard.

Very truly yours, F'

jzy h ..

C. W. Fay Vice President Nuclear Power Copies to NRC Resident Inspector NRC Regional Administrator, Office of Inspection and Enforcement, Region III

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