05000423/LER-1996-049-02, :on 961211,non-compliance to Non Class 1E Electrical Cable Separation Was Noted.Caused by Inadequate Electrical Separation Insp.Work Planning Process Procedures Have Been Revised

:on 961211,non-compliance to Non Class 1E Electrical Cable Separation Was Noted.Caused by Inadequate Electrical Separation Insp.Work Planning Process Procedures Have Been Revised

ML20141F491
Person / Time
Site:	Millstone
Issue date:	06/21/1997
From:	Danni Smith NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20141F482	List: 05000423/LER-1996-049-01, Forwards LER 96-049-01,documenting an Event That Occurred at Mnps,Unit 3 on 961211.Commitments Made within Ltr,Encl 05000423/LER-1996-049-02, :on 961211,non-compliance to Non Class 1E Electrical Cable Separation Was Noted.Caused by Inadequate Electrical Separation Insp.Work Planning Process Procedures Have Been Revised
References
LER-96-049-02, LER-96-49-2, NUDOCS 9707030012
Download: ML20141F491 (6)

LER-1996-049, on 961211,non-compliance to Non Class 1E Electrical Cable Separation Was Noted.Caused by Inadequate Electrical Separation Insp.Work Planning Process Procedures Have Been Revised

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(iv), System Actuation
4231996049R02 - NRC Website

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NRC FORM 366 U.s. NUCLEAR REGULATORY Commission APPROVED BY OMS NO. 315o-olo4 I

(4-9 51 EXPIRES o4/30/98 L$la*J?#lJ"er",o"JMPs!si f!"%s"%%%ro^*iM80 a'a"'?o'*in? *"'Maa 'nMl~"n~*,2:!s'?o *Mn LICENSEE EVENT REPORT (LER) 15 m^r'U'? ',"agaat/ gag;18;fm=/a*9yA~;gga g (See reverse for required number Of

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FACILITY NAME (1)

DOCKET NUMBER (2)

PAGE (3) l Millstone Nuclear Power Station Unit 3 05000423 1 of 5 l

TITLE (4)

Class 1E to Non-Class 1E Electrical Cable Separation Noncompliance EVENT DATE (5)

LER NUMBER (6)

REPORT DATE (7) oTHER FACILITIES INVOLVED (8) l MONTH DAY YEAR YEAR SEQUENTIAL Revision MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NUMBER 12 11 96 96 049 01 06 21 97 1

oPERATINo 5

THis REPORT is SUBMITTED PURSUANT To THE REQUIREMENTS oF 10 CFR 5: (Check one or more) (11)

MODE (9) 20.22o1(b) 20.2203(a)(2)(v) 50.73(a)(2)(i) 50.73(a)(2)(viii) l POWER 000 20.2203(a)(1) 20.2203(a)(3)(i)

X so 73(a)(2)(ii) 50.73(a)(2)ixi LEVEL (10) 20.2203(a)(2)(i) 20.2203(a)(3)(ii) 50.73(a)(2)(iii) 73.71 j

20.22o3ta)(2)(iii) 50.36(c)(1) 50.73(a)(2)(v)

Specify in. Abstract below 20.2203(a)(2)(ii) 20.2203(a)(4) 50.73(a)(2)(iv) oTHER

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20.2203(a)(2)(iv) 50.36(c)(2) 50.73(a)(2)(vil)

LICENSEE CONTACT FoR THis LER (12)

NAME TELEPHONE NUMBER (include Area Code)

David A. Smith, MP3 Nuclear Licensing Manager (8601437-5840 1

COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE

SYSTEM COMPONENT MANUFACTURER REPORTABLE

CAUSE

SYSTEM COMPONENT MANUFACTURER REPOR. ABLE TO NPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14)

EXPECTED MONTH DAY YEAR YEs No submission (if yes, complete EXPECTED sVBMissioN DATE).

DATE (15)

ABSTRACT (Limit to 1400 spaces, Le., approximately 15 single-spacedtypewrittenhnes) (16)

On December 11,1996, with the plant in Mode 5, it was identified that the spacing between a Class 1E and a non-Class 1E cable in the Cable Spreading Room did not meet the minimum separation distance specified in the Final

- Safety Analysis Report (FSAR). Inspections were performed to identify additional deviations. Inspections from March through May 1997 identified 976 deviations. The deviations with the exception of the three discussed below met operability criteria previously established within an electrical separation operability determination documenL On April 29 and May 21,1997, two instances where the separation distance between cables in the Instrument Rack Room, and one instance within a manhole, where the Sil-temp protective wrap was peeled back, were identified, resulting in electrical separation violations which were immediately corrected.

The results of the Wyle Test Report provide technicaljustification for the acceptability of electrical separation configurations with spacing less than those described in the FSAR. There were no adverse safety consequences from this condition, in that the unit has not experienced an event as a result of a failure in electrical separation nor has it experienced an event which was aggravated by a failure in electrical separation of circuits or equipment.

Training on electrical separation has been conducted for applicable plant personnel. Work planning procedures 3

have been revised to incorporate guidance for electrical separation inspection plan development. Identified electrical srparation deviations will be corrected or restored to compliance with the design basis prior to entry into Mode 4.

NRf' Fr)RLA 'I AA # A.OU 9707030012 970621 PDR ADOCK 05000423 UED

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• U.s. NUCLEAR REGULATORY CoMMISstoN (4 95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL REVISION i

Millstone Nuclear Power Station Unit 3 05000423 NUMBER NUMBER 2 of 5 96 049 01 1

TEXT (11more space is required. use additionalcopies of NRC Form 366A) (17)

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1.

Descriptien of Event l

On December 11,1996, with the plant in Mode 5, during an electrical separation inspection, it was identified that the 5 l

inch spacing between a Class 1E cable and a non-Class 1E cable in the Cable Spreading Room did not meet the 1 foot j

minimum horizontal separation distance between cables specified in the Final Safety Analysis Report (FSAR). As rzported previously in Licensee Event Report (LER) 96-015-02 and LER 96-045-00 electrical separation deviations had l l

been identified and inspections of various systems and areas were being conducted.

On December 12,1996, an engineering evaluation of the condition identified that it d:d not meet operability criteria previously established within an electrical separation operability determination document. An immediate notification was made on December 12,1996, for the originally identified electrical separation deviation pursuant to 10CFR50.72(b)(1)(ii)(B) as a condition outside the design basis of the plant.

Within Revision 0 of this LER, a commitment was made to perform electrical separation walkdowns on all areas subject to clectrical separation issues by August 1,1997, and report the results in a Supplement.

Based on the electrical separation deviations identified in LER 96-015-00, Supplements 1 and 2, it was decided to j

p:rform a self-assessment of electrical separation within the plant. The self-assessment was performed during the month of December 1996. During this self-assessment additional electrical separation deviations were identified. A comprehensive inspection program was developed. Based on the results of this self-assessment, walkdowns were performed of plant areas susceptible to electrical separation violations during the time period from March through May 1997. The inspections identified 976 deviations from electrical separation requirements. The deviations with the exception of the three discussed below met the operability criteria previously established within an electrical separation operability determination document. The three conditions are discussed below.

On April 29,1997, with the plant in Mode 5, during the electrical separation walkdowns, two separate conditions were id:ntified where a non-Class 1E lighting cable laid across uncovered cable trays containing Class 1E cables in the Instrument Rack Room. These two conditions violated the 3 foot minimum vertical separation distance between cables specified in the FSAR. These two conditions were immediately corrected as part of the inspections. On May 21,1997, it was identified that the Sil-temp protective wrap (a protective barrier) where Class 1E cables entered a duct (3DX903W32)in manhole 3EMH-3A was peeled back exposing the Class 1E cables, which resulted in an electrical srparation violation between non-Class 1E cables exiting adjacent ductlines. This condition violated the cable-in-air to cable-in-air separation requirement because the cables were not fully covered by the Sil-temp protective wrap as specified in the FSAR. The Sil-temp was immediately re-caulked to the duct seal to re-establish the barrier during the inspection.

These conditions were discovered when the unit was in an extended cold shutdown and as a result no immediate operator action was required. Detailed records of the individual electrical separation deviations are available at the Millstone Station.

• 'U.S. NUCLEAR REGULATORY CoMMisSloN (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NuM8ER (6)

PAGE (3)

YEAR SEQUENTIAL REVIStoN Millstone Nuclear Power Station Unit 3 05000423 NUMBER NUMBER 3cf5 96 049 01 TEXT lit more space is required, use additionalcopies of NRC Form 366A) (17) 11.

Cause of Event

The cause of these electrical separation deviations was inadequate electrical separation inspection by architect / engineering and utility quality control personnel during construction. Originally, a review of maintenance and modification records did not reveal any activities that might have impacted the electrical separation between these cables inside the Cable Spreading Room after building turnover. The originally identified electrical separation deviation was believed to have been an isolated condition that occurred during construction.

, However, based on tiie number and type of electrical separation deviations identified during March through May 1997 inspections, the failures to comply with electrical separation criteria appear to be the result both of inadequate installation and inspection prior to initial plant startup, and inadequate control during maintenance and modification activities after plant startup.

I Ill. Analysis of Event The FSAR specifies a minimum 1 foot horizontal separation between Class 1E and non-Class 1E circuits in the Cable Spreading Room. The original condition identified on December 11,1996, during an electrical separation inspection I

where the horizontal separation between a Class 1E cable and a non-Class 1E cable in the Cable Spreading Room was five (5) inches. Following this initially identified condition plant walkdowns were performed during the period between March through May 1997, to identify additional electrical separation deviations.

Elactrical separation criteria are described in Section 8.3.1.4.2 of the FSAR. FSAR Table 1.8-1 clarifies the application of the guidance of NRC Regulatory Guide 1.75, " Physical independence of Electrical Systems," to the facility. FSAR Table 1.8-1 states in part* " Analysis of minimum separation distance.. is accomplished by the following: Test and analysis performed to determine the separation requirements between Class 1E and non-Class 1E is presented in Wyle.

Test Report No. 47506-02". Prior to licensing, testing had been performed at the Wyle Test Laboratory to test the d sign adequacy of various worst case configurations of electrical raceways. Supplement 3 to the Millstone Unit 3 l

Safety Evaluation Report approved the revised electrical separation criteria based upon configurations tested by the Wyle laboratory. However, electrical separations of less than a foot between cables in the Cable Spreading Room were not specifically requested.

The results of the Wyle Test Report provide technicaljustification for the acceptability of electrical separation configurations with spacing less then those described in the FSAR. The 5 inch horizontal spacing condition originally id:ntified was within one of the test configurations evaluated within the Wyle Test Report. Consequently, this condition had minimal safety significance.

An operability determination document was developed to determine the impact on system operability of conditions id:ntified during the plant walkdowns. The electrical separation deviations identified were within configurations specified within the operability determination document developed based upon the Wyle Test Report, with the exception of the original condition and the three conditions previously discussed herein.

The condition where the Sil-temp barrier was peeled back identified during the inspections in May 1997 was also within tha test configurations evaluated within 4e Wyle Test Report. Consequently, this condition had minimal safety significance. The two separate conditions where a low voltage lighting cable was found laying across uncovered cable-

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• *U.s. NUCLEAR REGULATORY Commission I

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL REvlsloN Millstone Nuclear Power Station Unit 3 05000423 NUMBER NUMBER 4 of 5 96 049 01 TEXT (If more space is required, use additionalcopies of NRC Form 366A) t17) trays containing Class 1E cables in the instrument Rack Room, would in the event of a fault (single failure) result in a possible failure within only one division of Class 1E circuits. Therefore, equipment operability would still be within the criteria of the FSAR due to the redundancy between electrical divisions.

There were no adverse safety consequences from these conditions, in that, the unit has not experienced an event as a l result of a failure in electrical separation nor has it experienced an event which was aggravated by a failure in electrical s paration of circuits or equipment. However, the conditions identified are significant because they represent i

conditions outside the design basis of the plant.

IV. Corrective Action

For the original event, it was determined following discovery, that various components were affected, among those l

being the Component Cooling Water and Service Water Systems, resulting in the 'A' Residual Heat Removal and the 'A' Emergency Diesel Generator (EDG) Systems being declared inoperable. The 'A' EDG had previously been declared inoperable for other reasons. Entries were made into the applicable Technical Specification Limiting Conditions for Operation and repairs initiated to meet electrical separation criteria.

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The originally identified electrical aparation condition was restored to compliance with the criteria described in the i

FSAR on December 13,1996. Deviations identified during electrical separation walkdowns were reviewed versus an operability determination document. Those that did not meet operability requirements were reviewed for reportability and have been reported herein. The three conditions identified on April 29,1997, and May 21,1997, wtre restored to compliance with the FSAR on these dates.

The following corrective actions have been completed:

1.

Electrical separation walkdowns have been performed on areas subject to electrical separation issues. These electric # v paration walkdowns were completed in May 1997.

2.

Ac usenb> d in LER 96-015-04, the applicable work planning process procedures have been revised to l' corporab guidance for electrical separation inspectico plan development.

3.

i- % ced in LER 96-015-04, initial training on ehetri.;al separation has been completed. A training module i

on vectrical separation has been implemented as continuing training for applicable personnel from the implementing and Engineering departments.

Submittal of this supplement completes the reporting of the results of investigations into this issue. Should any significant electrical separation issues be identified during our ongoing design reviews, they will be reported in a supplement or LER as appropriate. One corrective action remains to be completed:

1.

Identified electrical separation deviations will be corrected or restored to compliance with the design basis prior to entry into Mode 4.

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• • U.s. NUCLEAR REGULATORY Commission (4 95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL REVislON Millstone Nuclear Power Station Unit 3 05000423 NUM8ER NUMBER 5 of 5 96 049 01 TEXT (11more space is required, use additionalcopies of NRC Form 366A) (11}

V.

Additional Information

None

Similar Events

Tho electrical separation deviations identified were identified as a result of inspections resulting from issues raised during the Configuration Management Program review process.

'1 LER 96-015-04 "Inadeauate Electrical Separation Between Redundant Protection Trains Associated with Reactor Trio Switches and Reactor Trio Breaker indicatina Liahts.*

This LER involved a noncompliance with electrical separation requirements between the manual reactor trip switch and the breaker indicating lights for redundant reactor protection trains.

LER 96-045-00

• Electrical Seoaration Desian Conflict with FSAR*

l This LER' involves several cases of electrical separation deviations dispositioned and approved by engineering during construction and early operation, not meeting the electrical separation criteria specified in the FSAR.

Manufacturer Data Ells System Code Not Applicable Architect Enoineer Stone & Webster Engineering Corporation i

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I NTsC FORM 366A (4 95)