ML19259B795

Forwards LER 78-113/03L-1

ML19259B795
Person / Time
Site:	Davis Besse
Issue date:	03/15/1979
From:	Murray T TOLEDO EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19259B796	List: ML19259B795 ML19259B798
References
L79-183, NUDOCS 7903230167
Download: ML19259B795 (1)

Text

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C TOLEDO o EDISDN March 15, 1979 L79-183 FILE: RR 2 (NP-33-78-135)

Docket No. 50-346 License No. NPF-3 Mr. James G. Keppler Regional Director, Region III Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Dear Mr. Keppler:

s Enclosed are three copies of Licensee Event Report 78-113 which has been updated.

The revisions to the report are indicated by a "1" in the lef t margin of the report.

Please replace your previous copies of Licensee ' Event Report 78-113 with the attached, revised copies.

Yours truly, Terry D. Murray Station Superintendent

• Davis-Besse Nuclear Power Station TDM/SNB/ljk Enclosure cc: Dr. Ernst Volgenau, Director Office of Inspection and Enforcement Encl: 30 copies LER 78-113, Rev. 1 Mr. William G. Mcdonald, Director Office of Management Information and Program Control Encl: 3 copies LER 78-113, Rev. 1 7903230%7 CDl SON PLAZr 300 MADISON AVENUE TOLEDO. Oh!O 43S52 THE TOLEDO EDISON COMPANY

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TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-78-135 PAGE 2 On November 17, 1978, Maintenance Work Order (MWO) 78-2673 was initiated to trouble-shoot the renewed signal fluctuations causing asymmetric rod alarms. On November 24, 1978, MWO 78-2683 was issued to implement Facility Change Request (FCR)78-501 which relocated API connections within the penetration by moving cable CCCRD 110A from T31-1-5 to TB2-21-25 on PCCSU. Work was completed on FCR 78-501 on December 7, 1978. On December 8,1978, the API was declared operable but the problem recurred shortly after.

On December 8,1978, under in'0 78-2864, Maintenance personnel cleaned and dried the connections on the position indicator for Rod 3-4. The cable from the position in-dicator to the bulkhead was replaced with a new cable and o-rings in connectors replaced. ST 5013.03 Sections 6.5, 6.7 and 6.10 for Rod 3-4 " rod Program Verifi-cation" was completed satisfactory at 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br />.

On December 10, 1978, MWO 78-2873, 78-2872, 78-2874 were issued to work on PI, -

penetration, cable. FCR 78-518 was Enplemented to jumper API to a new penetration.

On December 14, 1978, MWO 78-2887 was implemented. On December 15, under MWO 78-2889, a test of PI tube and antenna cable was conducted while the API cable was disconnected from penetration. Results indicated oscillation only on the PI side. When the pene-tration side was monitored, a steady signal resulted, indicating that the PI tube was the problen.

On December 19, 1978, under MWO 78-2873, the position indicator tube was replaced.

On December 20, 1978, under MWO 78-2908, and FCR 78-538, the API cable CCCRD110 .

was returned to its original location prior to FCR 78-501.

Diamond Powe , the position indicator vendor, was contacted and will further inves-tigate the f ailure of the position indicator tube.

Failure Data: There have been no previous occurrences of absolute position indica-tion inoperabilty for Control Rod 4, Group 3. There have been, however, previously reported occurrences of absolute position indicator inoperability due to component failure in the penetration area on Group 5, Rod 12. These were reported in Licensee Event Reports NP-33-78-02, NP-33-78-19, NP-33-78-26, and NP-33-78-38.

LER #78-113 i

• TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-78-135 DATE OF EVENT: November 10 and 17, 1978 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Absolute Position Indication for Group 3, Rod 4 inoperable.

Conditions Prior to Occurrence: On November 10, 1978, the unit was in Mode 1, with Power (MWT) = 1354 and Load (MWE) = 446. On November 17, 1978, the unit was in Mode 1, with Power (MWT) = 2770, and Load (MWE) = 923.

Description of Occurrence: On November 10, 1978 at 0425 hours0.00492 days <br />0.118 hours <br />7.027116e-4 weeks <br />1.617125e-4 months <br /> and on November 17, 1978, at 0624 hours0.00722 days <br />0.173 hours <br />0.00103 weeks <br />2.37432e-4 months <br />, fluctuating signals f rom the absolute position indicator for Control Rod 4 of Group 3 caused " asymmetric rod" alarms. Absolute position indica- ..

tion for this rod was declared inoperable at each of these times, placing the unit in the Action Statement of Technical Specification 3.1.3.3.

Technical Specification 3.1.3.3 states that all safety, regulating and axial power shaping control rod absolute position indicator channels and relative position indi-cator channels shall be operable and capable of determining the control rod positions within + 6.5% while the unit is in Modes 1 and 2.

Designation of Apparent Cause of Occurrence: On December 7,1978, af ter access to, 1 containment was permitted, the f ailure investigation of the absolute position indi'ca-tion for Control Rod 4 of Group 3 resumed by testing the individual components of ,

the PI s tring. The cause of the occurrence has been determined to be an intermittent failure of a component within the position indicator tube. ,

Analysis of Occurrence: There was no danger to the health and safety of the public or to unit personnel. Relative position indication, as well as zone reference indi-cation for Rod 4 of Group 3 were operable during the period that the absolute posi-tion indication was inoperable.

Corrective Action: On November 13, under Maintenance Work order 78-2648, Maintenrace personnel inspected PI cable connections at the PI tube and ae . coactor service structure bulkhead. A slight amount of moisture was found in the connector at the PI tube. The connector was dried and reconnected. On November 14, 1978, at 0215 hours0.00249 days <br />0.0597 hours <br />3.554894e-4 weeks <br />8.18075e-5 months <br />, Surveillance Test ST 5031.03, " Control Rod Program Verification" was com-pleted, and the absolute position indication for Rod 4, Group 3 declared operable.

The unit was removed from the Action Statement of Technical Specification 3.1.3.3.

LER #78-113