05000346/LER-2003-014, Re Steam Feedwater Rupture Controls System Re-Energizes in a Blocked Condition

Re Steam Feedwater Rupture Controls System Re-Energizes in a Blocked Condition

ML033520203
Person / Time
Site:	Davis Besse
Issue date:	12/16/2003
From:	Bezilla M FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NP-33-03-014-00 LER 03-014-00
Download: ML033520203 (9)

LER-2003-014, Re Steam Feedwater Rupture Controls System Re-Energizes in a Blocked Condition

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3462003014R00 - NRC Website

text

FENOC I~~~__*

5501 North State Route 2 FirstEnergy Nuclear Operating Company Oak Harbor, Ohio 43449 Mark B. Bezilla 419-321-7676 Vice President - Nuclear Fax: 419-321-7582 NP-33-03-014-00 Docket No. 50-346 License No. NPF-3 December 16, 2003 United States Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Ladies and Gentlemen:

LER 2003-014 Davis-Besse Nuclear Power Station, Unit No. I Date of Occurrence - October 17. 2003 Enclosed please find Licensee Event Report (LER) 2003-014, which is being submitted to provide vritten notification in accordance with 10 CFR 50.73(a)(2)(ii)(B) of an unanalyzed condition due to the discovery that the Steam Feedwater Rupture Control System (SFRCS) has an unexpected potential to re-energize in a blocked condition. The SFRCS is required to be operable in Modes I through 3 by the Davis-Besse Nuclear Power Station Technical Specification 3.3.2.2. In addition, due to the potential for the SFRCS re-energization in a blocked condition, this LER is being submitted in accordance with IOCFR50.73(a)(2)(i)(B) as a condition prohibited by the Technical Specifications.

Very truly yours, AWB/s Attachments cc:

Regional Administrator, USNRC Region III DB-I NRC Senior Resident Inspector DB-I NRC Senior Project Manager, USNRC Utility Radiological Safety Board

Docket Number 50-346 License Number NPF-3 NP-33-03-0014-00 Attachment Page I of 1 COMMITMENT LIST The following list identifies those actions committed to by the Davis-Besse Nuclear Power Station in this document. Any other actions discussed in the submittal represent intended or planned actions by Davis-Besse. They are described only as information and are not regulatory

commitments

Please notify the Manager - Regulatory Affairs (419-321-8450) at Davis-Besse of any questions regarding this document or associated regulatory commitments.

COMMITMENTS

DUE DATE Corrective Action to fix the SFRCS logic to prevent the Actuation Channel from re-energizing in a blocked configuration was performed in accordance with the Engineering Change process.

Following the modification, the four SFRCS logic channels were energized using the SFRCS Operating Procedure to verify that SFRCS logic channels do not assume the blocked condition upon restoration of power.

Complete.

Complete.

Abstract

On October 15, 2003, with the plant in Mode 5, the Steam and Feedwater Rupture Control System (SFRCS) Logic Channel 1 re-energized in a blocked condition.

While performing the initial investigation, on October 17, 2003, it was discovered that any of the four logic channels could be re-energized in a blocked condition, depending on different operating configuration conditions.

Therefore, this condition was conservatively reported to the Nuclear Regulatory Commission as required by 10 CFR 50.72(b)(3)(ii)(B), Notification Number 40256.

Subsequent investigation determined that the effect on plant operation is limited to a rupture on Once Through Steam Generator (OTSG) 2 with Logic Channel 4 re-energizing in a blocked configuration. If this postulated event occurred, Auxiliary Feedwater Pump 2 would continue to feed the ruptured OTSG.

This design condition has existed since 1988 following a modification to replace the SFRCS cabinets. Corrective Action has been completed which modified the SFRCS logic module to prevent the undesirable block from becoming enabled until the power supply voltage stabilizes and prevents the block initiation without operator action. Because SFRCS did not meet single failure criterion due to this condition, this event is conservatively reportable as an unanalyzed condition in accordance with 10 CFR 50.73(a)(2)(ii)(B). The condition also represented an operation or condition prohibited by the Technical Specifications and is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B).

NRC FORM 366 (7-2001)

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FAILURE DATA:

There have been no License Event Reports submitted by Davis-Besse Nuclear Power Station in the last three years, reporting an event due to the SFRCS Logic Channels re-energizing in a "Blocked" condition.

Searches conducted on the Corrective Action Program database and records management did not identify other previous similar events in the last three years for which corrective action could have been expected to prevent this occurrence.

Energy Industry Identification System (EIIS) codes are identified in the text as [XX].

NP-33-03-014-00 CRs 03-08917 and 03-08887