05000346/LER-1979-095-03, /03L-0:on 790925,auxiliary Feed Pump Turbine Steam Inlet Valve MS106 on Sys 1 Lost Its Indication.Caused by Loose Lamp Retainer Ring Which Grounded & Blew Control Power Fuse.Ring Was Tightened & Fuse Replaced

/03L-0:on 790925,auxiliary Feed Pump Turbine Steam Inlet Valve MS106 on Sys 1 Lost Its Indication.Caused by Loose Lamp Retainer Ring Which Grounded & Blew Control Power Fuse.Ring Was Tightened & Fuse Replaced

ML19254E245
Person / Time
Site:	Davis Besse
Issue date:	10/23/1979
From:	Beeler T TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19254E242	List: 05000346/LER-1979-095, Forwards LER 79-095/03L-0 05000346/LER-1979-095-03, /03L-0:on 790925,auxiliary Feed Pump Turbine Steam Inlet Valve MS106 on Sys 1 Lost Its Indication.Caused by Loose Lamp Retainer Ring Which Grounded & Blew Control Power Fuse.Ring Was Tightened & Fuse Replaced
References
LER-79-095-03L, LER-79-95-3L, NUDOCS 7910310369
Download: ML19254E245 (3)

LER-1979-095, /03L-0:on 790925,auxiliary Feed Pump Turbine Steam Inlet Valve MS106 on Sys 1 Lost Its Indication.Caused by Loose Lamp Retainer Ring Which Grounded & Blew Control Power Fuse.Ring Was Tightened & Fuse Replaced

Event date:
Report date:
3461979095R03 - NRC Website

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DOCKET NUf/ DER bd 63 EVENT DATE 74 7S REPOHT D ATE 80 EVENT DESCRIPTION AND PROB ABLE CONSEGUENCES h l o l 2 l l 0n September 25, 1974 at 0316 hours0.00366 days <br />0.0878 hours <br />5.224868e-4 weeks <br />1.20238e-4 months <br /> while performing ST 5071.04, " Auxiliary Feedwater I l System Channel Functional Test", the Auxiliary Feed Pump Turbine steam inlet valve MS196 a

3 o la l on system 1 lost its indication. The system was declared inoperable placing the unit i s ! l in the Action. Statement of Technical Specification 3.7.1.2.

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c_j i 2030 hours0.0235 days <br />0.564 hours <br />0.00336 weeks <br />7.72415e-4 months <br /> wh!1e troubleshooting MS106, MS106A (cross-connect from system 1 to 2) was l o

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[ i Lo j l Under Maintenance Work Order (SMO) 79-3033, the loss of ind4;ation of MS106 was deter-l mined to have been caused by a looje lamp retainer ring which grounded and blew the I

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[ij3) l f aulty R2 relay (Deutsch) for MS106A was replaced. Auxiliary Feedwater System I was l l declared operable by the successful performance of ST 5071.04 at 1810 hours0.0209 days <br />0.503 hours <br />0.00299 weeks <br />6.88705e-4 months <br /> on 9/27/79).

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DVR 79-141, 1%E Oc PREPARER Thomas P. Beeler PHONE.

TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEE "TAL INFORMATION FOR LER NP-33-79-111 DATE OF EVENT:

September 25, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURPERCE: Lost indication on MS106 and failuie of MS106A relay R2 Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MD:) = 2770, and Load (Gross E4E) = 918.

Description of Occurrence:

Un September 25, 1979 at 0316 hours0.00366 days <br />0.0878 hours <br />5.224868e-4 weeks <br />1.20238e-4 months <br /> while performing Sur-veillance Test ST 5071.04, " Auxiliary Feedwater System Channel Functional Test", valve MS106, Auxiliary Feedwater Pump Turbine Steam Inlet Valve 1-1 from Steam Generator 1-1 lost its indication. Auxiliary Feedwater System 1-1 was declared inoperable placing the unit in the Action Statement of Technical Specification 3.7.1.2.

This requires two independent auxiliary feedwater systems available while in Modes 1, 2, and 3.

With one system inoperabic, the inoperable system shall be restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in hot shutdown within the next 1.' hours.

On September 26, 1979 at 2030 hours0.0235 days <br />0.564 hours <br />0.00336 weeks <br />7.72415e-4 months <br /> while troubleshooting MS106, it was discovered that MS106A was not operating ',cause its closing relay R2 contacts were not closing. A.new relay was installed. While attempting to complete ST 5071.04 on September 27, 1979, at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br />, MS106A was not operating because its closing relay R2 ccatacts were not closing. A second new retty was installed. These relay failures are being reported to document a component f ailure.

Designation of Apparent Cause of Occurrence: MS106 was not operating properly because of a grounded control circuit which blew the control power fuse and ;aused its loss of all indication and control. MS106A was not opera:ing because closing relay R2 contacts were not closing. The problem was determined to be internal to the relay. The relay coil would pickup properly but its contacts would not close. The second failure on September 27, 1979 was corrected by installing a new relay. The new relay had to have its pins spread to make proper contact in the socket base.

Analysis of Occurrence:

There was no danger to the health and safety of the public or to station personnel.

Auxiliary Feedwater System Train 2 was operable had it been required.

Corrective Action

Under Maintenance Work 3rder (MWO) 79-3033, the first occurrence was investigated.

It was found that the ccatrol circuit was grounded at the local open indicating light circuit. The lamp retaining ring was tightened, wire re-terminated and control power fuse replaced. As a followup, MWO 79-3132 was issued LER #79-095 1245 349

TOLEDO E'#ISON COMPANY DAVIS-BFSSE NUCLEAR POWER STATION UNIT ONE PAGE 2 SUPPLE}' ENTAL INFORMATION FOR LER NP-33-79-111 to inspect additionallocal indicating lights for excessive loose retaining rings, sockets, etc.

There were no significant additional findings. The second occur-rence was investigated under MWO 79-3126. The defective R2 relay was replaced.

The pins on *he second relay were spread to assure proper contact.

Facility Change Request 79-3t.1 was written to evaluate the use of Deutsch relays in the Auxiliary Feedwater System. Auxiliary Feedwater Systea 1 was declared operable by the succes-sful performance of ST 5071.04 at 1810 hours0.0209 days <br />0.503 hours <br />0.00299 weeks <br />6.88705e-4 months <br /> on September 26, 1979.

Failure Data:

Previous failures of auxiliar) feedwater system relays have been reportcd in Licensee Event Report NP-33-79-94.

LER #79-095 1245 350