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

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Power GB Slade General Manager l'llWERINli MICHlliAN-S l'llOlillESS

. Palisades Nuclear Plant:

• 27780 Blue Star Memorial Hi~hway, Covert. Ml 49043

• April 24 , 1992

• Nuclear Regulatory Commission .

Document Control Desk

• Washington, DC 20555 DOCKET 50-i55 - .LICENSE DPR PALISADES PLANT -

LICENSEE EVENT REPORT 91-014-03, - SAFETY RELATED CIRCUITS ROUTED WITH OPPOSITE CHANNEL CIRCUITS - SUPPLEMENTAL REPORT . .

License~ Event Report (LER) 91-014:03 is .attach~d.

• 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 physi~al separation and channelization d~ficiency existed with* cabling

• • associated with three electrical schemes. In that LER we rioted that becaus~

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.

• deficienci~s, their stat~s~ and planned resolution. Supplement 2 to LER 91-014 provided information on a cabl~ s~paration and channelization

• • deficiency identified with pressurizer level circuitry* cable .. This attached

• supplement provides.informatiorr on one additional cable separation and *

~hannelization.defiGiency associated with the plants redundant*~ngineered safeguards roo~ ~ir 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 d 4 ; t ; c a f l i n e 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

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SAFETY RELATED CIRCUITS ROUTED WITH OPPOSITE CHANNEL CIRCUITS - SUPPLEMENTAL REPORT

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Through the on-going Palisades Configuration-Control Project a number of apparent discrepancies in circuit routing have been identified. Previ~us NRC correspondence dated September 4, 1990 and March 12,-19_91 provided details of the "Ci~cuit ~nd Raceway Schedule Enhancement Proje~t" 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 ~lectrical ~r protection system independence; or noncompliance with 10CFRSO, 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 promptly-correct~d~

The physical separation and channeli~ation deficierici~s that have been identified appear to result from two separate failures: 1) A non-uniform interpretation of design criteria for chann~lizing 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.

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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EV~NtDESCRIPTION T_he *Palisades Configuration Control Project (CCP) which was initiat~d 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-8~-147, 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 rout~ng .is not an issue, or the cirtuit mis-routing .is nrit a ~afety

' concern because the failu~e of the cfrc~it 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 p~ovided to the NRC in our letter dated Septembe~ 4, 1990. * ~ st~t~s update on the proje~t c was provided. i,n -our letter dated March 12, 1991.

At- the time of th*e disc<?very -~of 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 *outsid~ the des-ig!l _oasis of I

- . the pl ant. * * .

. Cause of the Event*

~he physical separation and-channelization deficiencies that have been _

id~ntified appear t~ result from two separate: failures: 1) A: non-uniform interpret~tion of design criteria for channelizing and routing el~ctrical circuits, and 2) the una~ailability of a single, complete and reliable source**

of design docum~ntation for electrical circuit r9Uting and channelization.

Analy~is 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 requ~st for information regarding the criteria and_

associated bases used at Palisades during initial design and installation of*

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

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separat~ raceway sy~tems; and that "physical separation; (dist~nce), is considered to ~e most reliable method of providing circuit separation and

• isolatton." ** * *

• 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.

these*channeliz~d raceways .. Thts method of providing physical separatio~

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_

. identified so far represents only,_a very small percentage (less. than orie percent) *of the over thirteen thous~nd* electrical cables that we have evaluated~ 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 di~crepancies in1he future~ We have also**

taken actions to address the physical separation. *and *channelization * . *

• deficiendes-whicb h.ave been.identified to date. * ..

The electrical circuit chanri~liiation and separat*i*o*n deficiencies which *have been ~valuated 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 ~hannelization discrepancies. As we have done in the past, we wiJl evaluate confirmed cable routing and separati~n discrepancies for safety-significance and *operability impact when they ~re identified, and*

. compensatory and corrective measures will be. pursued, as necessary ..

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• This _event is being reported under 10CFRSO. 73(a) (2)(1i) as a condition. outside

~the des1gn: basis of.the plant .. :*

Corrective Action* ..

• .. _Corrective. actions a~dressi ng .ci rc.uit channel i ti' -and separation . ta on .

defi-ciencie~ 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- lett~r. The_actions and their

.. FUrrent status are listed below: * *

• • .. L * .The* des-i gn *'and n ~ens 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 S~paration. Desig*n * ..

• • ,. C~iteria*~and Licens_i~g ~asis .. ". _* ... * ., . ... * . . *

.< . *.. * .'. ~. * . G~*i d~-~c~ *h~s~ been deve lOped Jn Admi ni strati v~

• Proc~dure ,'9 ~3~, ** . ** * .:** **'.

. . :;, -"Circu.it'. and Raceway Schedule!',~*. for contfol *and entry of _design* . ~ *~ *.::: . . _. -* ...

informat*ion-. in the)~a.~le_,*-~nd: Raceway Schedul_e (c~*sr datab~se . .

. :i.*,. *. . * * .** . , *,:* .*

o' C~ble ~outing.* requ.i ~'~merits and: .practi ~.ei ha~e **peen **_incorpo.rated- *i ntri * .. *.

Engilie~ring.-Guidelines: EM-22-.04~-- Ch'anne_l .Sepa*r~.tion ~- C'able;* * *':

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

• • • Verification;'" EM-22-06; ."~able Routing - EEQ Requirements;'~ ****: *.

EGAD-PROJ.--:08, "Cable Sizing* Gujd.eline >Amp~city;-" and EGAD'.. PROJ*-03; * **' *' *

"Electrical Engine_erjng *sep,arat:ion Criter_ia; Prac.tiC:es and*_, ,. - . . ,:.

Except.ions; * . *. * ., * * * .. :: .* .. ;

. .' 1**."* . **  : ' *, . '

4~ A p_hysical:;rev1ew of *installed cable: raceways h_as been performed. fo order to identify i.nstallati9i:is *th~t do not -meet. desig.n * .

>req_ufreinents;_;. * ...-*.*.:._ *,** * * .,*'.*

• ~

• 5;.*:~ Design tnforma~ion relative to the cha:~neli:£ation *and phy,sical

• roµting of electrical circuits and ra~eways will be erihanced._ Thts*-

attiori will tnclude validation ~nd.tcimpletion ~f informat.ion * .;:" ..

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

• . *

• comp_l ete *prior to ~eptember 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 revi~w.

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For the specific circuits in this LER, the Configu~ation 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 ~e~iewed.

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

• C.

• A further investigation of t~e original plant design basis for.

physical separation of safety-related ~trcuits was completed. Bas~d.*

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

• D. Each confirmed circuit channelization def1ciency *will be evaluated with regards to *equipment _opera bi 1ity 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 p~ovided in. the attachment to

.*this LER. . . . .

E. Physical separation of improperly channelized, safety"'.related circ~its will be established on a sched~le.consistent.wtth the

. safety significance of the deviation. * *

.. If 1t i's determined that' failure of the _improperly channelized, safety-related circuit does not ad~ersely affect ac~omplishment of.a

• . safety function, the circuit may be left as currently routed. Such*

conditions will be clearly documented in the* Circuit and raceway sc~edule~ * * * * *

• 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.

Addition~l fnfo~mation 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

'I' ... *.

LER 91-014 S~pplement 2 CONFIRMED CIRCUIT CHANNELIZATION AND SEPARATION DEFICIENCIES Scheme Scheme Name NUinber *Operable " Unreviewed

• Co11111elit of .. Safety Circuits Question 8293 Die~el Gener~tor 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.

S65 Reactor Prcitection 1 *. Yes No Failure of circuit d6e~ not System adversely affect accomplishment.of the safety function.

... .1 IP 73

• P~essurizer Narrow .,

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 W~ter 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 Fail~re of this circuit does not Skid adversely aff~ct accomplishment-of the safety function in short term.

(2-4.hours). Long term operator

.actions are addressed in *plant proced~re~. 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

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Attachment * '.

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 S~fety 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 conditi~n is being evaluated to determine if the circuits should .be reverified to provide proper physical. separation, .or if

• justifita~ion ~xtst~ to request NRC approval of a deviation from the Regulatory Guide 1.97 requirements .

2

. . . Attachment .* ., . .*' '.

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

Scheme Scheme Name Number . Operabl~ Unrevi ewed . C011111ent of.** * * , Safety Circuits Question IL34 Pressurizer_'Wide :Range -No : ves*

• Redundant insirumentS have cables

-and Level * ~ . *~

rout_ed through one cable tray. .Both IL37 '.

• level instruments are identified i.n I J.'

• _the Te~hniial .Specifications .. Th~

cables will be re-routed to provide

~eparation ~s f~quired i~: FSAR

• Sect lon 8. 5.. 3. I.

'8131 Engineered Safeguards 2 Yes .. *No* The fan*coolers are left channel but and Room Coolers fans V27A the power c~bles fot the fans ate 8133 and V27C .routed with right channel cables,.

through a control room floor elettrical penetration. Failure ~f

-these circuits .does not adversely affect the accomplishment of the-*

.. safety function as the redundant' -

coolers cabl~s ,ate routed separat~ly

.. ' *~

f~om these-circuits. *

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