ML18058A204

LER 91-014-01,on 910709,cofiguration Control Project Number of Apparent Discrepancies Routing Have Been Identified. Caused by Physical Separation & Channelization Deficiencies. Reconstituted Design for channelization.W/920214 Ltr

ML18058A204
Person / Time
Site:	Palisades
Issue date:	02/14/1992
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 9202210364
Download: ML18058A204 (7)

Text

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- G B Slade . - _

General Manager POWERING MICHIGAN'S PROGRESS Palisades Nuclear Plant: 27780 Blue Siar Memorial Highway, Covert. Ml 49043 Febr~ary 1~, 1992

. Nuclear. Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 LICENSE DPR-20 .PALISADES PLANT .

LICENSEE EVENT REPORT 91-014, SUPPLEMENT 1 - SAFETY RELATED CIRCUITS .

. ROUTED WITH OPPOSITE CHANNEL CIRCUITS* . .

Licensee Event Report (LER) 91-014-1 is at~ached. Thi~ ~upplemental. ,.

repbrt provides additional irrformation not ~ontained in the original submittal. These changes are indicated by a vertical Hne in the right

• hand margin. This event is reportable to the NRC per *

• 10CFR50.. 73(a)(2)(iiJ, as a condition outside the design bas.is.

~~

Ger~ld B Slade

• General Ma_nager CC Administrator, Region.Ill, USNRC

• NRC Resident Insp~ctor - Pal.isades Attachment 9202210364 920214 PDR ADOCK 05000255 S PDR '

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• 1.1.. -....-~ - . , . . _ . , _ _ , _ 11- 1111 Through the on-going Palisades 'configuration Control identified. Project a number of routing have been Previous apparent discrepancies in circuit 1991 provided NRC correspondence dated September 4, 1990 and March 12, details of the 11 Circuit and Raceway Schedule Enhancement Project" and status of the projeCts activities. The *electrical circuit .channelization and . separation deficiencies which have.been evaluated *at thi.s time, while not conforming ta ~SAR criteria in a11 *respects, have resultt;!d in i dent ifi ca ti on of very few conditions i nvo.l vi ng a loss of electrical or protection system independence; or noncompliance with 10 CFR 50, Appendix R requirements.

• In those few*cases, two to date, compensatory measures in plant Technical and corrective actions have been taken as stipulated Specifications and/or the condition was pr9mptly corrected. At the timeto of the event the plant was operating at about 70%.power and escalating is reportable as a ..

foll power fo 11 owing a *Short outage. This event

• Condition outside the design basis of the pl ant.

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The Palisades Co~figu~ation Ccintrol Project (CCP) whic~ was irtitiated in 1987 included an effort to verify and correct plant electrical drawings, including the plant circuit and raceway schedule.* This effort involved development of a circuit and raceway schedule data b~se, as well as verification of selected portions of circuit routin~~. Throtigh this effort a n_umber of apparent discrepancies in circuit* routing have been identified. This event invol~~s approximatelj 40 circuits which were believed to be safety-related circuits routed with opposite channel*

circuits. Previous pla~t deviation~reports involving apparently misrouted circuits includ~ O-PAL-89-147, D~PAL-90-4Q, D-PAL-90-221, arid O-PAL-90~222. *All *of the apparently misrouted circuits from these earlier-deviation r~ports that have been evaluated, have been I*

dispositioned as either not being safety-related and therefore .

channelized circuit routing is not an issue, or* the circuit misrouting is.

not a safety concern because the failure of the circuit does not le~d to -*

. unde~irable consequences (i.e. the circuit fail~ safe). Additional_

background and information on the CCP circuit and raceway enhancement .

project was provided to the NRC in our letter dated_ September 4~ 1990 .. A.

status update on the project was provided in our letter dated March. 12, *

.1991.

At the ti me of the event 'the p1ant was opera.ting at about 70% POY'er and esca1ating to full power following a. sh~r~outage~

• Cause of the EVent

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The _physical_ separation a*nd channelization. deficiencies.thatAha*ie been identified appear to ~esult from two sepa~ate failures: . 1) K non~uniform interpretation of design criteria for channelizing and rquting electrical circuits, and. 2) the unavailability:of a single, ~omplete and reliabl~

source of design doc~mentation for electr~cal *circuit routing and chan~elization. ..

• Ana.lys is of the Event Cable Separation Design Criteria The design criteria which were originally used at Palisades to provide physical independence between redundant 'electrical circuits were submitted to the Atomic Energy Commission (AEC) on May 28, 1969; This submittal contained, in pa~t, our re~ponse to a request for information regarding the triteria and associated bases used at Palisades duri-ng initial design arid installat1on of electrical circu.its. The guidelines that are currently used dur1ng design of electrical cables and raceways are essentially unchanged from those of the original design period and

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• TtXTiw--*are*remct~~n~~li.'tcseC:tion 8.5.3.l. FSAR Section 8.5.3.1 states that circuits belonging to safety-related power distribution channels~ reactor protection system ~hannels, engineered safeguards channels or other safety-related system channels will be run in sep~rate raceway systems, and that "physical separation, (distance}, is considered to be most reliable method of providing.circuit separation and isolation."

In practice, the design criteria for physical separation and independ~nce of electrical circuits are primarily satisfied by r6uting electrical cables in channelized cable raceways, and by maintaining a separation diitance between these channelized raceways~ This method of providing.

physical separation between redundant el~ctrical circuits meets the intent of curreritly acc~pted standards and guidelines and has been reviewed and determined to be acceptable.* Palisades was designed prior t6 issuance of Regulatory Guide 1.75, "Physical Independence of

• Electrical Systeins," the AEC General *Design Criteria for physical.

independence of electrical circuits, or the associated IEEE standards

. (IEEE 279, IEEE 384).

Circuit Separation and Channelization Anomalies_ .

We have identified several examples where the channelization ~f installed

• electrical cables does not satisfy our original design criteria. The

~ctual n~mber of electrical cable separation and channelization

. discrepancie.s identified so far represents only a very small percentage . "

(les~ than one percent) of the o~er thirteen thousand el~ctrical cables .

that we have ev,aluated. As. a' result of these cable routing anomalies, we

. have undertaken a programmatic effort to identify and resolve those physical separation and channeliz~tion discrepancies that may exist, and we have taken steps to prevent promulgation of similar discrepancies in the. future.. We have al so. taken actions to address the physical

• separation and channelizatidn deficiencies Which have been identified to date.

• The ele~trical circuit. channelizati~n and separati~n deficiencies which

. have been evaluated at this time, while not conforming.to FSAR criteria in.all respetts, have resulted in identification of very few safety-significant conditions involving a loss bf:electrical or protectibn system .independence or noncompliance with 10 CfR 50, Appendix R

. requirements. In those few cases, two to date, compensatory measures and*

corrective actions hav~ been taken.as stipul~ted in plant Technical Specifications _and/or the condition was promptly corrected.

Pa 1i sades has taken an aggressive position in ifs response to the tdentified electrical cable routing and channelization discrepancies through the. Electrical Cable and Raceway Separation Issue Resol_ution Plan. Thi~ plan addresses the causal fact6rs for these coriditions and proposes actions to prevent reoccurrence. The key ptovisions of this plan include: 1) 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) evalu~tion and

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0 5 0 0 0 2 5'591 ..:...01 4 - 0 l 0 4 OF 0 5 T'IXT.'*--r~l1't.1"m'l~"iam;it'i1t'ied cable* routing and channelization discrepancies.

• As we.have.done in the past, we will - _ _ .

evaluate confirmed cable routing and separation discrepancies for safety-significance and 9perability impact when they are identifi~d, and

_compensator~ and corrective measures wi 11 be pursued, as necessary.

This event is being reported under -10CFR50.73{a)(2){ii) as a condition outside the design basis of the plant. _ -

Corrective Action -

Corrective actions addressing circuit channelization and separation deficiericies began.with the Electrical .Cable and Raceway Separation Issue Resolution Plan. A summary and *implementation schedule for these actions was pr6vided in our September 4, 1990, *"Submittal of Additional information Related to th~ Circtiit and Raceway Schedule Enhancement Project," and a status update was provided in our March 12, 1991 letter.

The actions and their current status are listed below: -*

l. The design and licensing basis for channelization and physical

• separation of electrical circuits h~s been reconstituted and

. consolidated in a siri9le document, the "Electrical Separation Design Criteria and* Licensing Basis." -

2. Guidance has been developed in Administrative Pr-ocedure 9.35; "Circuit and Raceway Schedul~," for control and ent~y of design information in. the Cable and Raceway ..Schedule . .

(CRS) database. -

~

3. Cable routing ~eq~irements and ~ractices have been incotporated.

into Engineering Guidelines: EM-22-04, "Channel Separation -

Cable Routing Instructions;" EM-22-03, "Fir:e Protection - Cable Route Verification;" EM-22-06, "Cable Routing - EEQ Requirements;" 1-EGAD-PROJ-08, "Cable Sizing Guid!:!l ine - Ampacity;" and EGAD-'-PROJ-.

03, "Electrical Engineering Separation Criteria, Practices and Exceptio.ns." * *

4. A physical review of installed cabl~ raceways has been performed

- in order to identify installations that do not meet design

• I-requirements.

s.* Design information relative to the channelization and physical

. routing of electrical circuits and raceways will be enhanced.

This action wil} include validation and completion of information contained in. the CRS database and is c~rrently*expected to be

• complete prior to September 30, 1992.

6.* Electrital cable separation arid channelization anomalies identified during our review of physical raceway installation~

will be evaluated and appropriately d:ispositioned. The schedule

• for resol~tion of these items is dependent on the number and type of items identifi~d during the review.

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. For the sp~cific circuits fo this LER, the Configuration Control Proje.ct (CCP)*Electrical Cable and Raceway Separation Issue Resolution Plan is intended to address the root cause of this event and no furthei

~orrective actions to prevent recur~ence are proposed at this time.

• Remedial actions for the.recently identified specific circuit routings are as follows: * . .* . * . .*

A.* Since only class 1E circuits require physical separation of channelized circuits, the safety classification of each potentially misrouted circuit will be reviewed.

B. The in~plant routing of each potentially misrouted safety-related channelized circuit will be verifi~d. * * *

• c; A fu~thet irivesti~a{ion of th~ original plant design basis for .

physical separation of safety-related circuits w~s completed .

. . Based on the results of this review,* tbe EGAD-PROJ-03, "Electrical Eng~neering Separatiori Ciiteria, Practices, and exceptions," was *

.revised. .

I D. Each confirmed circuit channeliiation defici~ncy ~ill be evaluated with regards to equipment operability and l_OCFR50. 59. Appropriate compensatory measures and. corrective actions as ~ti pul ated in

• plant Technical Specifications will also be taken. A list of

• confirmed circuit channelization deficiencies is prov.ided in the

. attachment to this LER; * *

• E.

• Ph~si~al separation of improperly ch~nnelized, safety-related

• circuits will. be established on a schedule consistent with the safety significance of the deviation.

If it is determined t_hat failure of the improperly channelized, safety-reJ~ted circuit . does not adversely affect accomplishment of a safety function, the circuit may be left as currently routed.

Such conditions will be clearly documented in the circuit and

.raceway schedule ..

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 *inspections are.not needed to assure that circuit. channelization deficiencies have been identified.

Additional Information*

None

Attachment LER 91-014 CONFIRMED CIRCUIT CHANNELIZATION AND SEPARATION DEFICIENCIES Scheme. Scheme Name Ntn>er of Operable UnrevieWed Carment '

Circuits Safety Question B293 Diesel Generator Room Cool i ng 2 No No When the condition was* discovered a temporary Fan V24C .- modification was performed to remove reliance on' V24C.

• This c.ircuit has been. re-routed to provide:

proper physical separation ..

S65 Reactor Protection System 1 Yes No Failure of circuit does n'ot adversely affect accomplfshment-of the safety function.

IP 73 Pressurizer Narrow Range 1. No Yes When the condition was discovered a temporary Pressure modification was performed to disconnect the circuit. Proper physical separation wi 11 be

. . established .

SOB Servjce Water System Valves 1 Yes No Failure of this circuit does not adversely affect accomplishment of the safety function.

G06R. Diesel 1-2 Auxiliary Skid 1 No No Failure of this circuit. does not adversely ~ffect accomplishment of the safety function in short term

( 2-*4 hours). Long term operator actions are addressed in plant procedures . .Proper physical seoarat ion wi 11 be established.

S16 Component Cooling Water Valves 1 Yes No Failure of .this circuit does not*adversely affec(

accomplishment of the safety function.

D408 Control Room HVAC Emergency 1 Yes No Failure* of this *circuit does not adversely affect Actuation accomplishment of.the safety function; however*,

0

- position in~ication for ventilatiOn system dampers.

may be lost. This Regulatory Guide ~.97, Category 2 instrumentation is not required to .meet the single failure criterion .

521 and Waste System Containment 19 Yes No Failure of these clrcuits does not adversely affect S22 Isolation Valves accomplishment of the Safety function; . however, containment isolation valve position indication niay Miscellaneous Containment be lost. This Regulatory Guide 1.97, Category 1 S25 and Isolation Valves 17 Yes No instrumentat iOn is required .to meet the .single.

S26 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 recogniz_e that 'phys ica 1 separation criteria .were not met. This condition is being evaluated to :

-. determine if the circuits*should be reverified to provide proper physical separation, or if justtfication exists to request NRC apprrival of a deviation from the Regulatory Gulpe 1.97 requirements.