ML18058A380

LER 91-014-03:on 910709,discovered That Safety Related Circuits Routed W/Opposite Channel Circuits.Caused by non-uniform Interpretation of Design Criteria for Routing Circuits.Plan Developed to Address issues.W/920424 Ltr

ML18058A380
Person / Time
Site:	Palisades
Issue date:	04/24/1992
From:	Roberts W, Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-014, LER-91-14, NUDOCS 9205010259
Download: ML18058A380 (9)

Text

consumers Power l'llWERINli MICHlliAN-S l'llOlillESS . Palisades Nuclear Plant:

• 27780 Blue Star Memorial Covert. Ml 49043

• April 24 , 1992

• Nuclear Regulatory Commission . Document Control Desk

• Washington, DC 20555 DOCKET 50-i55 -.LICENSE DPR-20 -PALISADES PLANT -GB Slade General Manager LICENSEE EVENT REPORT 91-014-03, -SAFETY RELATED CIRCUITS ROUTED WITH OPPOSITE CHANNEL CIRCUITS -SUPPLEMENTAL REPORT . .

Event Report (LER) 91-014:03 is

• This event is _reportable to the. NRC per 10CFR50.73(a)(2)(ii), as a condition outside the design basis. ' *-The original.

LER 91.-014 was dated August 8, 1991, and provided notification.

• that a separation and channelization existed with* cabling **associated with three electrical schemes. In that LER we rioted that of an ongoing Electrical Cable and Racew.ay Separatibn Issue Res.elution Plan, we exp.ected to. submit additional information on this subject, as we expected that additional deficiencies may be identified.

Supplement 1 to LER 91.-014, .*dated February 14, l992, prov.ided information concerning additional.

• their and planned resolution.

Supplement 2 to LER 91-014 provided information on a and channelization

• • deficiency identified with pressurizer level circuitry*

cable .. This attached *supplement provides.informatiorr on one additional cable separation and

• associated with the plants safeguards coolers. Because programs afe in place to address these* deficiencies, and have been described in earlier revisions of this LER, no *major changes have beeh made to .the descriptions in this LER except for the addition of the latest.deficiency to the attachment to the LER. Any changes d4;t;cafline in the right.hand margin. Gerald B Slade General Manager CC Administrator, Region III, USNRC NRC Resident Inspectdr

-Palisades

• Attachment 9205010259 920424 PDR ADOCK 05000255 S PDR NllCtso:r** LICENSEE EVENT REPORT (LEA) U.I. NUCLIAll lllGULATOllY Cm9t1DIC*

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' SAFETY RELATED CIRCUITS ROUTED WITH OPPOSITE CHANNEL CIRCUITS -SUPPLEMENTAL REPORT . Liii NUMeElll.Cll llll'OllT DATE 171 . OTHlll 'ACILITIU llrVOLVIO Ill' *YEAR f:;}: :.: MONTH DAY *YEAR

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DA TEJ -IX'ICTl!D IUIMISllON OATE 11111 1\81TflACT

/Limit ,. l<<IO -* I.a .. -x;;,,,,.,y fl,_ li'WI*-* ry_rre,, /in.V 1111 . Through the on-going Palisades Configuration-Control Project a number of apparent discrepancies in circuit routing have been identified.

NRC correspondence dated September 4, 1990 and March 12,-19_91 provided details of the Raceway Schedule Enhancement and status of the projects .activities.

The electrical .circuit channelization and separation deficiencies which have been evaluated at this time, while not conforming to FSAR criteria in all res_pects, have resulted in identification of very few conditi.ons involving a loss of protection system independence; or noncompliance with lOCFRSO, Appendix R requirements".

In those few cases compensatory measures and corrective actions have been taken as stipulated in plant Technical Specifications and/or the condition was The physical separation and that have been identified appear to result from two separate failures:

1) A non-uniform interpretation of design criteria for and routing electrical circuits, and 2) the unavailability of a single, complete .and reliable source of desfgn document*tion for electrical circuit routing and channelization.

I At the time of the discovery of the latest discrepancy (engineered safeguards room cooler cfrcuitry channelization}, the plant was shutdown for a refueling outage..

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T_he *Palisades Configuration Control Project (CCP) which was in 1987 'included an effort to.veri.fy and correct plant electrical drawings, including the plant circuit and raceway schedule.

-This effort involved development of a circuit and raceway schedule data.base, as well as-verification of selected portions.of circuit routings.

Through this effort a number of apparent discrepancies in circuit routing have been identified.

-This event involves_

approximately

• 40 circuits wh.ich were bel ie-ved. to be safety-related.

cj rcuits routed with opposite channel circuits.

Previous plant deviation reports *involving apparently mls'-routed Circuits include D-PAL-90-40, D-PAL-90-221, and D-PAL-90-222.

All of the apparently mis-routed circuits*

from these earlier deviation reports that have been evaluated,.

have been dispositi.oned as either notb"eing safety-related and therefore channelized circuit .is not an issue, or the cirtuit mis-routing .is nrit a

' concern because the of the does not lead to: undesirable consequences (i.e. the circuit fails safe). Additional backgrbund and* information on the CCP circuit.and raceway_ enhancement

• project was to the NRC in our letter dated 4, 1990.

• update on the was provided.

i,n -our letter dated March 12, 1991. At-the time of th*e disc<?very the 'latest discrepancy

• (engineered safeg-uards

• roc;>m *cooler.s circuitry Channelization), the plant was shutdown for a refueling

-outage.* This event 'is :reportable as _a condition the des-ig!l _oasis of --. the pl ant. * * . Cause of the Event* physical separation and-channelization deficiencies that have been _

appear result from two separate:

failures:

1) A: non-uniform of design criteria for channelizing and routing circuits, and 2) the of a single, complete and reliable source** of design for electrical circuit r9Uting and channelization.

of the Event .*.. .. Cable. Separation_

Design Criteria The desig_n criteria wfrich were or-ig.inally used at Palisades to provide ---physical independence between redundant electrical tircuits were submitted to the Atomi.c Energy Commission (AEC) on May 28, 1969. This submittal contained, in part, our response to a for information regarding the criteria and_ associated bases used at Palisades during initial design and installation of* -

circuits.

The that are currently used during design of electrical cables and rateways are essentially unchanged from those of the "original design period and are in FSAR Section 8.5.3.1. FSAR Section 8.5.3.1 states that circuits belonging to safety-related power distribution channels, reactor system channels, engineered safeguards channels or other _safety-related syste!:ll channels will be run in c I . . -* *-

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911 -o 11 I 4 -013 Palisades Plant raceway and that "physical separation; is considered to most reliable method of providing circuit separation and

• isolatton." ** *

• 01 3 *In practice, the.design criteria fbiphysical separation and independence of. electrical circuits are primarily satisfied by* routing electrical cables in chanryelized cable raceways, and by maintaining a separation distance between.

raceways .. Thts method of providing physical between redundant e_lectrical circuits meets the intent of currently accepted standards and guidelines and has been reviewed and determined tobe .acceptable.

Palisades was designed pri.or to issuance of Regulatory Guide .* I. 75., "Physical Independence of Electrical Systems," the AEC General Design * *. Criteria for physical independence of electrical circuits, or.the*asspciated IEEE standards (IEEE 279' IEEE 384) . . ' . Circuit Separatjon and Channel izatipn Anomalies

• > We have identified several examples where the cha*nnelization of installed . electrical cables does .not satisfy our original design criteria .. The actual . *number of electrical cable_ separation and channelizat1on discre,pancies_

011 . identified so far represents only,_a very small percentage (less. than orie percent) *of the over thirteen electrical cables that we have As a res.ult of these cable routing anomalies, we 'f1ave unde.rtaken a*

• progral!'lmatic effort to identify and resolve those physfr:a1 separation and .. channelization discrepancies that may exist, and we have.taken steps to

• prevent prcimulgation of iimilar in1he We have also** taken actions to address the physical separation.

• and *channelization

• .. * *deficiendes-whicb h.ave been.identified to date. * .. The electrical circuit and separat*i*o*n deficiencies which *have been at this time, while not cdnforming t6.FSAR criteria in all respects, have resu.lted in identification of very few safety-significant

• conditions involving a loss of electric;al or protection

_system independence or *.noncompliance with. IOCFRSO, Appendix R requirements.

• In those few cases. . .. comp_ensatory measures and corrective actions h'ave been taken as stipulated . in plant*Technical Spec'ifications and/or the condition was promptly c,orrected

.. * . Palisades has taken an aggressive pos.ition i.n its response to the identified eleetrical cable routing and channelization discrepancies

• through the Electrical .Cable and Raceway Separation*

Issue Resolution Plan .. This plan* :addresses the causal factors for these conditions and proposes actions to prevent reoccurrence.

The key provisions of this pl an include:

• I') publication of clear procedural ,guidance relative to cable routing design . . criteria, 2} availability of reliable circuit design-information, 3) field *review of installed raceways, and -4) evaluation and resolution of identified cable routing*and discrepancies.

As we have done in the past, we wiJl evaluate confirmed cable routing and discrepancies for safety-significance and *operability impact when they identified, and* . compensatory and corrective measures will be. pursued, as necessary

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• This _event is being reported under lOCFRSO. 73(a) (2)(1i) as a condition.

outside des1gn: basis of.the plant .. :* Corrective Action* .. * .. _Corrective.

actions ng .ci rc.uit channel i ta ti' on -and separation . .

began with _the Electrical Cable and Raceway Separation Issue . *

• Resolution Plani *A suimriary anq implementat:ion schedule for these ac;tions was provfded fo our September 4, 1990, "Submittal of. Add,.itfonal informati_on

• Related to the-Cir*cuit and Raceway Schedule Enhancement Project," and .a status update was* provide4 in our-March 12, 1991-The_actions and their .. FUrrent status are listed below: * * * .. * *"***.*, ** .. L * . The* des-i gn *'and n i ng :basis.: for thannel i zat.i on .and phys i ca i. * * .. : separation*

of elect.rical circuits has been reconstituted

_and * .. . . . *consolidated ,in a single.:dotument,_

the "Electrical Desig*n * **,.

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been deve lOped Jn Admi ni strati *

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and Raceway for contfol *and entry of _design* informat*ion-.

in Raceway Schedul_e

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• • peen **_incorpo.rated-

• i ntri * .. *.

Ch'anne_l C'able;* * *':

• Routing* Instr_uctions;'" . .EM-:22-03, *"Fire Protection-

-Cable *Route .... *** Verification;'" EM-22-06; Routing -EEQ

• • • • *. EGAD-PROJ.--:08, "Cable Sizing* Gujd.eline and EGAD' .. PROJ*-03;

• **' *' * **'. .. "Electrical Engine_erjng

• sep,arat:ion Criter_ia; Prac.tiC:es and*_, ,. -. . ,:. Except.ions;

• . *. * . , * * * .. :: .* * * ... , .. ; . .' 1**."* . ** : ' A p_hysical:;rev1ew of *installed cable: raceways h_as been performed.

fo order to identify i.nstallati9i:is do not -meet. desig.n * . >req_ufreinents;_;.

• .. .-*.*.:._

• ,** * * .,*'.*

• Design relative to the

• and phy,sical

• roµting of electrical circuits and will be erihanced._ ,_-. attiori will tnclude validation informat.ion

• .. . contained.

in the .CRS database *and is currently expected to be *. *

• comp_l ete *prior to 30, 1992. * " .. : .;:" .. . . . . 6. * -Electrical cabie*:sepa-ration and channelization*

anonial ies fdentified . . during our review of physical *raceway installations .will .be . evaluated and appropriate_ly dispositioned..

The sc_hedule*

for* ,. re solution of these i terns *iS. dependent on the number and' type of* . . items identified during the . . . ** *, . '

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.,.,i71 .--For the specific circuits in this LER, the Control Project (CCP) Electrical Cable and Raceway Separation Issue Resolution Plan is intended to address the root cause of this event and no further corrective actions to

• prevent. recurrence are proposed at this time. Remedhl actions for the recently identified specific circuit routings are as follows: ,* A.* Since only class IE circuits require physical separation of . . channelized circuits, the safety classification of each potentially mis-routed circuit will be

• B. -The in-.plant routing of .each potentially' mis-routed safety-related channeli.zed circuit wilr verified.

• C.

• A further investigation of original plant design basis for. physical separation of safety-related was completed.

on the results of this review, the EGAD-PROJ-03, "Electrfcal Separation Criteria, Practices, and was revised. * * *

• D. Each confirmed circuit channelization def1ciency

• will be evaluated with regards to *equipment

_opera bi 1 ity and 10Cl'R50.

59; 'Appropriate

• compensatory measures and corrective actions as stipulated in.plant . . . Technical Specifications will also be taken .. A list .of confirmed . *. circuit channelization deficiencies is in. the attachment to .*this LER. . . . . E. Physical separation of improperly channelized, safety"'.related will be established on a the .. safety significance of the deviation.

• * .. If 1t i's determined that' failure of the _improperly channelized, safety-related circuit does not affect of.a *. safety function, the circuit may be left as currently routed. Such* conditions will be clearly documented in the* Circuit and raceway

• * * * *

• F. Confidence in the accuracy *of the.circuit routing data in.the Circuit and Raceway Schedule was evaluated,.

and it was determined that additional verification inspettions are not needed to assure that circuit channelization deficiencies have been identified.

Previous submittals of this lER, dated August 8; 1991, February 14, 1992 and March 10, 1992 have identified information on other.cable separation discrepancies.

,. *,

Attachment LER 91-014 2 'I' ... *. CONFIRMED CIRCUIT CHANNELIZATION AND SEPARATION DEFICIENCIES " Scheme Scheme Name NUinber *Operable Unreviewed

• Co11111elit of .. Safety Circuits Question 8293 Room 2 . No No When: the erinditicin was discovered

a. Cooling Fan V24C . ' *temporary modification was performed to remove reliance on V24C;' This . -circuit has been re-routed to provide proper physical separation.

Reactor Prcitection

.. S65 1 *. Yes No Failure of circuit not System adversely affect accomplishment.of the safety function.

IP 73

• Narrow ... . 1 No Yes When the condition was discovered a Range Pressure . ., . . temporary modi fi.cati on was performed

.. to discorinect the circuit.

• Proper. physical separation will be .. *established . sos Service System 1 . Yes . No Failure of this c i r*cu it does not Valves adversely affect accomplishment of .. the safety function . " G06R Diesel 1-2 Auxiliary 1 *No. No of this circuit does not Skid adversely accomplishment-of " the safety function in short term. (2-4.hours).

Long term operator .actions are addressed in *plant . . "

Proper physical . separation will be established . .. Sl6 Crimponent Cooling J . Yes No Failure of this circuit does not Water Valves* adversely affect accomplishment

• of the safety

• furict ion ..

• 1

• Attachment

• '[r .. * '. LER 91-014 Supplement 2 Scheme Scheme Name Numb£!r. Operable Unreviewed C011111ent of Safety .. Cfrcuits Question 0408 .Control Rooin HVAC 1 Yes . No -failure of thts circuit does not Emergency.Actuation adversely affect accomplishment of the safety function; however, position indication for ventilation system dampers may be lost. This Regulatory Gui de 1. 97, Category 2 .. instrumentation is not required to meet the single failure criterion; S21 and Waste System . 19 Yes No Failure of these circuits does not S22 *Containment Iso1ati-0n adversely affect accomplishment of Valves *the function; however, containment

• isolation valve position S25 and Miscellaneous 17 Yes No indication may be lost. This S26 Containment Isolation Regulatory Guide I. 97, Category 1 Valves instrumentation is required to*meet . . the single failure criterion.

The . ' instrumentation was *not upgraded with regards to physical separation when Regulatory Guide 1 .. 97 *was imposed by NRC Generic Letter 82-33 . . This was due to our failure to . recognize that physical separation criteria were not met. This is being evaluated to determine if the circuits should .be reverified to provide proper .. physical.

separation, .or if

• to request NRC ,. approval of a deviation from the . . . Regulatory Guide 1.97 requirements . 2 Scheme IL34 -and IL37 '8131 and 8133 Scheme Name Pressurizer_'Wide

Range Level * ;,. . . , '. .. Engineered Safeguards Room Coolers fans V27A and V27C . ! . *'* * .. . . . Attachment

.* ., . . '. *' *' ** LER 91:-014. ,Suppl emetit:. 2 *:: .* *.,* Number .

of.** * * , Circuits I J.' 2 -No : Yes *.*** .. ; .. .. *. . . '* Unrevi ewed . Safety Question ves* * "* .. *No* ' .. . * , t I',* J ' . . * .. . ,* . ' ... ***** ... . ' ... **. . . **' .. *"'"** .*., C011111ent Redundant insirumentS have cables rout_ed through one cable tray. .Both *level instruments are identified i.n *_the .Specifications

.. cables will be re-routed to provide FSAR

• Sect lon 8. 5 .. 3. I. The fan*coolers are left channel but the power fot the fans ate .routed with right channel cables,. through a control room floor elettrical penetration.

Failure -these circuits .does not adversely affect the accomplishment of the-* safety function as the redundant'

-coolers ,ate routed these-circuits.

• . > ' . . *' *I .* *-.: .