ML18059A888

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LER 94-005-00:on 940125,metal Cable Tray Separation Barriers Missing from Certain Vertical Cable Trays.Caused by Inadequate Field Walkdown.Existing Plant Drawings Revised to Show Field Conditions of Missing barrier.W/940314 Ltr
ML18059A888
Person / Time
Site: Palisades Entergy icon.png
Issue date: 03/14/1994
From: Hillman C, Rogers D
CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-94-005, LER-94-5, NUDOCS 9403210007
Download: ML18059A888 (5)
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Text

consumers Power David W. Rogers .

Plant Safety and Licensing Director POWERIN&

NllCHl&AN'S PRO&RESS Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 March 14, 1994

( .,

Nuclear Regulatory Commission Document Control Desk

  • Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -

LICENSEE EVENT REPORT 94-005 - LACK OF PHYSICAL SEPARATION BETWEEN THE REDUNDANT CHANNELS OF SAFETY-RELATED INSTRUMENTATION CIRCUITS Licensee Event.Report (LER)94-005 is attached. This event is reportable in

.accordance with 10CFR50.73(a)(2)(ii)(B) as a condition outside the design basis of the plant. This LER will be supplemented.

David WRogers

Plant Safety and Licensing Director

.CC Administrator, Region Ill, USNRC NRC Resident Inspector - Palisades Attachment 9403210007 940314 PDR ADOCK 05000255 s ' PDR A CM5 ENERGY COMPANY

NRC F°"" 311 U.S. NUCLEAR REGlA.ATORY COMMISSION 19-831 .

APl'ROVED OMB NO. 3150-<>104 EXPIRES: 1131 /115 LICENSEE EVENT REPORT (LER)

FACILITY NAME 111 DOCKET NUMBER 121 PAGE 131 Palisades Plant I I I I I I I o *s o o o 2 s s 1 I oF o 14 nnE~I LACK OF PHYSICAL SEPARATION BETWEEN THE REDUNDANT CHANNELS OF SAFETY-RELATED TN~'T'RTT~ l<'.N'T'A'T'Tnl.1 r. T~r'.TTT'T'C:

EVENT DATE Ill LEA NUMBER Ill REPORT DATE 111 OTHER FACILITIES INVOLVED Ill SEQUENTIAL .. REVISION FACILITY NAMES MONTH DAY YEAR YEAR NUMBER NUMBER MONTH DAY YEAR N/A 9 4 914 O*I 01 5 q 0 op ll 4 9 I 4 NIA 0 1 1°1°1°1 I 6

THIS REPORT IS SUBMITTED P.URSUANT TO THE REOU1REMENTS OF 10 CFR I: IC'-k - ,,,,,_. ol tn. followingJ 1111 OPERATING Nt--T'""'20~.~.0~2~1b1~----~-.,---------...,...-r---------....-..---------I I

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&0.131a1121Ciii1 LICENSEE CONTACT FOR THIS LER 1121

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  • 60.731*11211xl NRC Form* 311AI NAME .. .TELEPHONE NUMBER AREA CODE l .

Cr.is T. Hillma~, Staff Licensing Engineer s I , I s I 1 I s I 41. - 1. a I s I , I 3 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 1131 MANUFAC* REPORTABLE.* MANUFAC* REPORTABLE CAUSE' SYSTEM. COMPONENT TIJRER . TO NPROS 'CAUSE SYSTEM COMPONENT TURER. TO NPllDS I I I .I **. I I iI I I I I I I' I I

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I. I I I I I SUPPLEMEN.TAL REPOf!T EXPECTED 1141 MONTH DAY YEAR EXPECTED rnYES~~.:..,_,_~l'fe~lu~~SSION~TEl: .:hNO t-:-"'::-~~~.~~~~~~-""---~~~~~~-'"----~~-'--~;.__~.;.r.....;.;....i....;;:..~J.......;..~.Jj SUBMISSION DATE 11111 0 .14 l l.5 914 I ABSTRACT*IUnWr ID 1400 _ .. Le., _ _ ,.,_,!"-,.,,,,._ ry,..writtWt -*I 1111 .

On January 25, 1994, at approximately 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />; with the plant operating at 100% .~

power, it was. discovered through:a,cable tray walkdown that metal cable tray separation. i barriers were missi.ng from certaip :v.ertical cable trays that contain redundant instrumentation:thannels of reactor protection and en~iheered safeguards systems. The physical sepa~ation of the instr~m~ntation channels js required by IEE~ 279, *

  • Sect j on 4. 6. :. * : * . , ..
  • Initially, the affected caples were determined to be operable using procedures*,

en~ineering judgement, and previous analysis. *Further investigation determined that the guid~~ce p~pvid~d in plant procedures was~not applicable to th~ ,cable t~ay conditi9ns described m *this event.:* Jherefore, .a failure modes and effect*s analysis (FMEA) will be performed prior to plant*heat-up from the current maintenance outage to determine if plant operability is affected by this conditiQn. ~* ..

The. cause* for this event was ani inadequate field walkdown' during original plant construction. ' ** "

  • Corr~ct i.ve. *action for thts *event . includes performing a FMEA to. determine systems .

operability, .reviSing exist.ing plant drawings to show actual field conditions of missing barriers, developing a 11.h~ssons :.1 earned 11 memoranqum to alert pl ant personr:ie l about missing separation barriers, perfprming additi_onal inspections to verify that other required cable tray separation barrie*rs have been installed, and installing metal barriers in the currently identified ~able trays during the 1996 refueling outage.

' ,/

., 19*83) APPROVED OMB NO. 3150-0104 EXPIRES: 8/31185 LICENSEE EVENT REPORT !LERI TEXT CONTINUATION FACILITY NAME 111 DOCKET NUMBER 121 lER NUMBER 131 PAGE 141 SEQUENTIAL I I REVISION YEAR NUMBER NUMBER Palisades Plant

! 0 I 5 I 0 I 0 I 0 I 2 I 5 I 5 I9 I4 I- I0 I0 I 5 I- I0 I0 I0 I2 I I0 OF ~

EVENT DESCRIPTION On January 25, 1994, at approximately 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, with the plant operating at 100%

power, plant personnel were conducting a walkdo~n of cable trays to resolve inconsistencies between the circuit and raceway schedules and plant cable tray layout drawings. The walkdowns were being performed to correct the inconsistencies in support of circuit analyses for 10CFRSO, Appendix R work. The circuit and raceway schedules showed that the instrument cables were routed through a divided tray.but plant cable tray layout drawin~s indicated that, a separation barrier was not installed in the cable tray. The separation barrier was confirmed to be missing by visual inspection of the cable tray. . l

)

The cable trays in this event are vertical cable trays that contain redundant I

'I instrumentation channels of reactor protection [JC] and engineered safeguards systems I

[JE]. The physical separation of the instrumentation channels is required by IEEE 279, Section 4.6. .The metal cable tray barriers were found to be missing in cable trays XU-109, 3XU-109 (both located in the lC switchgear room), XU-111 and 3XU-lll (both located in the cable spreading room) which contain ll) the primary coolant temperature channels (TE-0112HA, TE-0112HC, TE-Oll2CA, and TE-0112CC), and (2) the pressurizer pressure safety injection channels (PT-0102A and PT-0102C).

Initially, an operability determination was performed using the guidance provided in a Pali~ades Engineering Aid (EGAD), EGAD-ELEC-15, "Electrical Control Panel Separation Criteria, Practices, and Exceptions," engineering judgement, and previous analysis, and concluded that the missing cable tray barriers would not render the safety related systems incapable of performing their design basis function. The evaluation was reviewed by plant personnel on February 10, 1994, at which time it was determined that this event was reportable as a condition outside the design basis of the plant. The basis for this reportability determination was that the separation requirements for redundant safety channels of a safety-related system had not been met.

Upon further investigation of the basis for conclusions developed in the EGAD, it was determined that the guidance provided in the EGAD was not applicable to the specific cable tray conditions described in this event. Therefore, a failure modes and effects analysis (FMEA) will be performe.d to ~etermine the operability of the reactor* protection (RPS) and engineered safety features (ESF) systems with cables not being properly separated. With the plant currently in cold shutdown, none of the affected systems are required for op~rability in this condition. The FMEA will be completed prior to entering a plant condition where the cables and their systems are required to be operable.

This: event is reportable to the NRC in accordance with 10CFR50.73{a){2){ii){B) .as a condition outside the design basis of the plant.

.! 19-83) APPROVED OMB NO. 3160-0104 EXPIRES: 8/31 /86

.i LICENSEE EVENT REPORT (LERI TEXT CONTINUATION FACILITY NAME l1I DOCKET NUMBER l2l LER NUMBER (31 PAGE 141 SEQUENTIAL REVISION YEAR NUMBER NUMBER Palisades Plant oI sI oI oI oI 2 I sI sI9 I4 I- IoI oI sI - Io Io I 0 13 I IoI4 oF CAUSE OF THE EVENT The tause for this event was an inadequate field.walkdown during Driginal plant construction.

ANALYSIS OF THE EVENT In the original plant design, separation of instrument and control circuits for protection systems was provided by installing metal barriers in the cable trays. This method of separation was a backfit. During construction, problems with control circuit.

cable separation on protection systems occurred when it was recognized that some protection circuits were pulled before the cable tray layouts were completed.

Therefore, some control circuit cabling was installed without proper separation.

However, these errors were supposedly discovered with quality assurance checks performed during the construction phase, and many control circuit cables had to be re-pulled.

In an IEEE paper entitled "The Evolution of Palisades Plant Instrumentation & Controls Based on IEEE 279 (Feb. 1971)," the Palisades construction phase problems with separation of control cabling for protection systems as required by IEEE 279 were described. The IEEE paper stated that during construction, a 100% quality assurance check was made of the engineering rif all electrical schemes to assure that the schemes were '.being separated accurately by the.computer program used to assign cable tray routings. In addition, according to the paper, construction company field engineers audited 10% and CPCo field engineers audited 5% of all cables being installed for reactor protection and engineered safeguards systems. The missing cable tray barriers were apparently not discovered as part of that original walkdown.

Safety Significance and Operability Because of the previously identified problem with cable separation at Palisades, we have reviewed the alternatives to resolving the issue and have developed an Engineering Aid (EGAD) to assist in the analysis of cable separation issues. EGAD-ELEC-15, "Electrical Control Panel Separation Criteria, Practices, and Exc~ptions," and EGAD-ELEC-3, "Electrical Engineering Separation Criteria, Practices, and Exceptions," define the separation requirements for electrical panel circuits. During the evaluation of this event, we believed that the conditions described in the EGAD would adequately address the postulated fault scenarios for the cables described above.

Through further investigation of the b~sii for conclusioris developed in the EGAD, it was determined that the cables described in this event were not covered by the conditions described in the EGAD. Therefore, a failure modes and effects analysis (FMEA) will be performed to determine the operability of the systems affected by this lack of separation. With the plant currently in cold shutdown, none of the affected systems are required for operability. However, the FMEA will be completed prior entering a plant condition where the cables and the associated equipment are required to be operable.

NRC Form 388A U.S. NUCLEAR REGULATORY COMMISSION 19-83) APPROVED OMB NO. 3160-010<4 EXPIRES: B/31 /86 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION FACILITY NAME 11 I DOCKET NUMBER 121 LER NUMBER (3) PAGE 14)

SEQUENTIAL REVISION YEAR NUMBER NUMBER Palisade~ Plant I I I I I2 Is Is o s o o o 9 14 - o I o I s - o lo o 4I oF o 14 CORRECTIVE ACTION Correttive action for this event includes the following;

1. Revise existing plant drawings to show actual ,field conditions of missing ba.rri ers.

2~ Develop a "lessons learned" memorandum tb alert plant personnel to the existing condition (i.e., missing separation parriers) and the root cause for this condition.

3. Install metal barriers between XU-109 and 3XU-109, and XU-111 and 3XU-lll during the 1996 refueling outage.
4. Review the cable and raceway schedule for required separation barriers and compare this result to the cable tray layout drawings to verify that metal barriers are shown on the drawings. If the barriers are not shown on the cable tray layout drawing, a pl ant wa 1kdown wil 1, be performed to verify the information. In addition, 10% of the cable trays will be inspected to provide further assurance that required barriers have been installed.*

ADDITIONAL INFORMATION None

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