ML18057A979

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LER 91-009-00:on 910519,qualified Core Exit Thermocouple Occurred & Unable to Be Repaired While Plant Is at Power. Caused by Failure of Instrument.Corrective Action Document Initiated to Document event.W/910614 Ltr
ML18057A979
Person / Time
Site: Palisades Entergy icon.png
Issue date: 06/14/1991
From: Hillman C, Slade G
CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-009, LER-91-9, NUDOCS 9106240324
Download: ML18057A979 (4)
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consumers Power GB Slade General Manager POWElilNli MICHlliAN'S PROliRESS Palisades Nuclear* Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 June 14, 1991 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -

- INFORMATIONAL LER 91-009; QUALIFIED CORE EXIT THERMOCOUPLE INOPERABLE AND CANNOT BE REPAIRED WHILE THE PLANT IS AT POWER.

Informational Licensee Event Report {LER)91-009 {Qualified Core Exit Thermocouple Inop~rable And Cannot be Repaired While the Plant is at Power)* is.

attached. This event is reported in accordance with a proposed Palisades Technical Specifications change currently under review by the NRC.

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. Gera 1d B Slade General Manager CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachment

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LICENSEE EVENT REPORT (LERI U.1. NUCLEAll llEGULATORY CCMl*ION

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FAC_ILITY NAME l1l DOCKET NIA9Ell 121 I Palisades Nuclear Plant 0 16 IO IO IO I 21515

  • 1 loF 0 I 3 TITLE (4)

. Qualified Core Exit Thermocouple Inoperable and Cannot Be Repaired While the Plant is at 1>0¥ 7

ej IVINT DATE 1111 LEI! NUMBER 1111 llEl'OllT DATE 17) OTHEll FACILITIU INVOLVED Ill MONTH QAY YEAR YEAR  ;:;:;:;:;: SEQUENTIAL ::::::::: REVISION MONTH OAY YEAR FACILITY NAME8. DOCKET NUMIERISI

NUM*ER  ::::::::: NUM*ER NIA 0161010101 I I o Is 119 9 1 911 - olo 19 - q0 Oj6 11 4 9 ll N/A 0161010101 I I Ol'lllATING THIS llEPORT_ll IUIMITTED PURIUANT TO THE REQUlllEMENTI OF 10 CFll .§: (CMclc one or,,,.... of Iii* foll-fll) (111 I

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AREA CODE Cris Hillman, Senior Engineer 611 {> 716 f 1-18 19 1113 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRllED IN THll REl'OllT 1131.

.CAUSE SYSTEM COMPONENT MANUFAC* MANUFAC-TUR ER TURER I *I I I I I *I I I I I I I I I I I I I I I I I I I I I I IUl'PLEMENTAL REPORT EXPECTED 11.41 MONTH DAY Yi'AR EXPECTED SUBMISSION I YES (If va. comp/oro EXPECTED SUIJMISSION DA TEI DATE 1151 I I I AalTllACT (Limlr ID 14()() -

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I ABSTRACT On May 19,. 1991, at 1903 hours0.022 days <br />0.529 hours <br />0.00315 weeks <br />7.240915e-4 months <br />, with the plant operating at 100% power, qualified core exit thermocouple (CET) No. 16, was declared inoperable due to inaccurate readings. The method of discovery was erratic readings on the primary information processor (PIP).* A work order was written to troubleshoot and*repair CET 16 and the CET was listed on the limiting condition of operation (LCO) board. The work order for CET 16 was relea~ed for repair on May 20, 1991, at 1419 hours0.0164 days <br />0.394 hours <br />0.00235 weeks <br />5.399295e-4 months <br />, with repairs being initiated at that time.

Repairs were attempted by the Instrument & Control Department (l&C), however, none of the repair techniques that had been successful in the past were successful on this occasion. On May 21, 1991 it was determined that CET 16 could not be_ repaired while the plant was at power, thus CET 16 was declared inoperable.

The cause of the event was a failure of the instrument.

A corrective action document was initiated to document the event and to ensure that the 30 day special report required by the proposed technical specifications via administrative procedures was submitted.

NRC Form :IN 19-831

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U.I NUC~fAlll llEGULATORY CC*M1a10..

LICENSEE EV REPORT (LERI TEXT CONTINUATIO A"'ROVEO OMI .. o 3150-41~

ex"RES Br.JI '115

'-'CILITY NAMI 111 DOCKET NU. . Ell 121 Liii N~lll 111 Palisades Plant TEXT llf - - ia ._w, - .__,. /WfC Fotrrl _..,, 1171 EVENT DESCRIPTION-On May 19, 1991, at 1903 hours0.022 days <br />0.529 hours <br />0.00315 weeks <br />7.240915e-4 months <br />, with the plant operating at 100% power, qualified core exit thermocouple (CET) No. 16 [IP;TI], was declared inoperable due to inaccurate readings. The method of discovery was erratic readings on

  • the primary information processor (PIP). A work order was written to troubleshoot and repair CET 16 and the CET was listed on the LCO Board~ The work order for CET 16 was released for repair on May 20, 1991, at 1419 hours0.0164 days <br />0.394 hours <br />0.00235 weeks <br />5.399295e-4 months <br />, with repairs being initiated at that time. Repairs were attempted by the .

Instrument &Control Department (I&:C), however, none of the repair techniques that had been successful in the past were successful on this occasion. On May 21, 1991 it ~as determined that CET 16 could not be repaired while the plant was at power, thus CET 16 was declared inoperable; Proposed Technical Specifications, dated September 2, 1988, Table 3.17.4, Item 22, states that 11 * *

... , either restore the inoperable channel(s) to OPERABLE status within 7 days if repairs are feasible without shutting down or prepare and submit a special report to the commission (NRC) within 30 days outlining the action taken, the

~ause rif the inoperability and the plan~ and schedule for restoring the syst~~

to OPERABLE status. 11 _

CAUSE OF THE EVENT The cause of the event was the failure of the.jnstrument.

ANALYSIS OF THE EVENT The core exit thermocouples (CET) provide a continuous readout of the temperature of the primary coolant leaving the core region. Each of the four quadrants of the core is equipped with thermocouples, four of which. are provided with environmentally qualified electrical connectors and cabling inside containment, for a total of sixteen qualified thermdcouples. The four thermocouples in each quadrant are then divided into two separate and distinct electrical channels to ensure redundant capability. During this particular

  • event, CET No. 16 failed. The apparent cause of th~ failure was an open lead between the thermocouple and the recorder. The remaining three thermocouples in the quadrant are operable at this time, therefore, there was no loss of monitoring capability. The appropriate administrative controls, such as the initiation of the work order and the placing of the thermocouple on the LCO-Board, were utilized to initiate repairs to the inoperable CET. Following the required job planning, troubleshooting and repair was initiated on May 20, 1991. ' .

U.I "'UCCEAll "EOUcATORY COMl.llAIOO.

LICENSEE EVE-REPORT ILEA) TEXT CONTINUAT10r9 EXPIRES 8/31 '85

'4CILITY N4MI 111 LU! N~ll! Ill ~AOI l:tl Palisades Plant 0 1s I 0 I 0 I 0 I 2, s, s 9 11 - 0 I 01 9 - 0I0 01 3 OF 0 13 TEXT,,,,,_. -  ;,._.w. - - N l t C ~ .-.i*.11171 CORRECTIVE ACTION CET 16 was declared inoperable on May 19, 1991, at 1903 hours0.022 days <br />0.529 hours <br />0.00315 weeks <br />7.240915e-4 months <br /> and cannot be repaired while the plant is at power. Repair or replacement of CET 16 to return it to an OPERABLE status will be completed during the 1992 refueling outage, currently scheduled to begin in February 1992. A corrective action document was initiated to document the event and to ensure that the 30 day special report was submitted., ~

ADDITIONAL INFORMATION An informational LER, submitted May 9, 1991, documented a previous failure of CET 16 and its subsequent repair.

Proposed revisions to the Palisades Technical Specifications are currently under review by the NRC. This informational LER fulfills the administrative requirement of submitting a special report in accordance with the proposed technical specification, Table 3.17.4, Item 22, dated September 2, 1988.

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