ML18059A632

LER 93-014-00:on 931207,determined That Containment Electrical Penetrations Did Not Meet Design Criteria Specified in FSAR & TS Due to Inadequate Design Control. Appropriate Remedial C/As Will Be evaluated.W/940106 Ltr

ML18059A632
Person / Time
Site:	Palisades
Issue date:	01/06/1994
From:	Hillman C, Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-014, LER-93-14, NUDOCS 9401140099
Download: ML18059A632 (5)

Text

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.,I GB Slade General Manager POWERING MICHIGAN'S PROGRESS Palisades Nuciear Plant: 277e0. Blue Star Memorial Highwa~. Covert, Ml 49043 .

January 6, 1994 J

Nucl.ear *Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -

LICENSEE EVENT REPORT 93-014 - FAILURE OF ELECTRICAL CONTAINMENT PENETRATIONS TO. MEET DESIGN FEATURES DESCRIBED :IN TECHNICAL SPECIFICATIONS AND FSAR Litensee Event Report (LER)93-014 is attached. This event is reportable in accordarice with 10CFR50.73(a)(2)(ii)(B) as a condition outside the design basis of the plant.

Gz::~,£,*

General Manage~ - ..

CC Administrator, Region III, USN.RC NRC Resident Inspector - Palisades Attachment 9401140099 940106 r*

PDR ADOCK 05000;)55 '

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.. A CM5 ENERGY COMPANY

NRC Fonn 3118 U.S. NUCLEAR REGUlATORY COMMISSION 111:831 APPROVED OMB NO. 3160-0104 EXPIRES: B/31 /86 LICENSEE EVENT REPORT (LERI FAC:UTY NAME 111 DOCKET NUMBER 121 PAGE 131 Palisades Plant 015101010121515 . 1 I 0 14 OF TinEPAILURE OF ELECTRICAL CONTAINMENT PENETRATIONS TO MEET DESIGN FEATURES DESCRIBED IN

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EVENT DATE 161 LER N.UMBER 181 . REP.ORT DATE 1111 OTHER FACILITIES INVOLVED 181

>: SEQUENT!~ REVISION FACILITY NAMES MONTH DAY YEAR YEAR NUMBER I<. NUMBER MONTH DAY YEAR N/A o I 6 I o I o I I I o

i I 2 0*1 7 9 3 913 oI ll 4 01 o 01 1 01 6 9 I. 4 N/A 0 1 1°1°1°1 I 6

THIS REPORT*IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR I: IC/Wck..,,. Ol""'°'9of11N following) 1111 OPERATING N

I 20.4021bl 20.4061cl 60. 7 31all2Jlivl 73.711bl MODE 181 POWER' LEVEL 1101 do Io - 20.4061*111 Jlil 20.4061*111 Jliil -

60.3111cll11 60.3111cll21 60.731all2JM 60.731*112Jlviil 73.711cJ OTHER (Specify in A119u..,

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20.4061*111 Jlivl 60.731*11211iil 60.731*112JlviiiJIBJ NRC Form 388AJ

• * * ) **\ < * // ; \ 20.4061a111 JM 60.73(*112Jliiil 60.731all2Jlxl LICENSEE CONTACT FOR THIS LER 1121 NAME TELEPHONE NUMBER Cris T. Hillman, Staff Licensing Engineer COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 1131 sARIEA1cl°Es I 7 I I 4 I -I aI s I I 3 s

1 CAUSE SYSTEM COMPONENT MANUFAC*

TUR ER REPORTABLE TO NPROS /)'( CAUSE SYSTEM COMPONENT MANUFAC*

TUR ER REPORTABLE TO NPRDS I I I I I I *1 I !ti'. I I I I I I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED 1141 I* I. I I I I. I I MONTH DAY YEAR EXPECTED n YES Vf yH, compi.r. EXPECTED SIJBMISSION llA TEI ~NO SUBMISSION DATE 1161 I I I ABSTRACT UJmit to 1400 .,,..... i:e .. _.,,,m.re1y fiftfffl llingle--* typewritten line*I 1181 O~ Dece~ber 7, 1993, at 1240 hours0.0144 days <br />0.344 hours <br />0.00205 weeks <br />4.7182e-4 months <br />, with the plant operating at 100% power, ft was determined that the containment electrital penetrations in the north and southwest penetration rooms did not meet all the desi~n criteria specified in the Palisades Final Safety Analysis Report (FSAR) and the Techn1cal Specifications. In each room, a non-seismic nitrogen system is connected to each electrical penetration between the double barriers. Furthermore, the bottles and connecting pigin~ for the nitrogen system to the southwest penetration room _lie outside the auxiliary ui ding and, therefore, are not tornado protetted. .

• The cause of this event w~s inadequate design contiol. The design of the electrical.

penetrations was modified in 1970 and again in 1982 without recogniiing all of the design requirements of the electrical penetrations as contai~ment isolation boundaries.

Corrective action fot this event includes evaluating avpropriate actions to address the deficiencies in the electrical.penetration design, eva uating the co~tainment isolation boundaries for the electrical penetrations, incorporating electrical v*enetration design require~ents f9r the nitrogen suepJ{ into plaryt desi~n docu~eryts, imp ementiryg,permanent corrective action for the electrica penetration desifin deficiency, and providing a lessons learned memo to ~lant engineers emphasizing t e evaluation of functional interfaces when making c anges to plant equipment.

• ./ NRC Form-3HA U.S. NUCLEAR REGULATORY COMMISSION 19-831 APPROVED OMB NO. 31~104 EXPIRES: 8/31186 LICENSEE EVENT REPORT ILERI TEXT CONTINUATION FACILITY NAME (1) DOCKET NUMBER !21 LER NUMBER !31 PAGE !41 SEQUENTIAL REVISION

. YEAR NUMBER NUMBER PALISADES PLANT 0 I6 I0 I0 I0 I2 I6 I6 9 I3 - 0*1 1 I 4 - 0 I0 0 12. OF 0 I4 EVENT OESCRIPTiON

• On 0,ecember 7; 1993, at 1240 hours0.0144 days <br />0.344 hours <br />0.00205 weeks <br />4.7182e-4 months <br />, with the pl ant* operating at 100% power, it was determined that the containment electrical penetrations [NH;PEN] in the north and southwest penetration room~ did.not meet all the design criteria specified in the Palisades Final Safety Analysis Report (FSAR). The deficiency was identified during design engineering of a modification t~ the nitrogen supply for the north penetration room.

Technical Specification 5.2.2a states that all penetrations through the steel-lined concrete structure for electrical conductors, pipe, ducts, air locks, and.doors are of the double-barrier design. FSAR Section 5.8.6.2.2 also desc~ibes the electrical containme~t penett~tions as being of a double barrier design. In additiori, FSAR Section

.5.8.6.2 states that all containment penetrations are seismic and tornado protected. The penetrations in the north and southwest penetration rooms do not meet all of these requirements in that, in each room, a non-seismic nitrogen system is connected to each electrical penetration between the double barriers. Furthermore, the nitrogen bottles arid connecting piping for the nitrogen system to 'the southwest penetration room lie outside the auxiliary building and, therefore, are not tornado protected .

. This event is reportable to the NRC in.accordance with*IOCFR50.73(a)(2)(ii)(B) as *a condition outside the design basis of the plant. I CAUSE OF THE EVENT The cause of this event *was inadequate design control. The design of the electrical penetrations was modified in 1970 without recognizing all of the design requirements of the electrical penetrations as containment isolation boundaries. The design was further modified in 1982 without recognizing the design requirements of the penetrations.

ANALYSIS OF THE EVENT The design specification for the electrical penetrations (E-20) required a double barrier design with a 1/4-inch test port o.n the exterior side of the containment. The original intent was to install a threaded plug in the electrical penetration which could be removed to allow for leak rate testing.

• The design was modified in 1970, prior tQ initial plant operation, to provide a bottled nitrogen supply, pressure gauges, a tubing -network, and fill connections to each electrical penetration for the purpose of pressurizing the space between the double barriers with nitrogen as a m~ans of controlling corrosion. The 1970 modification was apparently performed without consideration of seismic requirements. No record of this modification exists, other than a letter directing its installation. In 1982, the nitrogen bottles for the southwest penetration rdom were relocated to the turbine building to resolve a personnel safety concern during bottle repl~cement. The 1982 modification did not consider the tornado protection r~quirements for the system when the nitrogen bottles were relo~ated.

NRC F0tm 3HA U.S. NUCLEAR REGULATORY COMMISSION lf-831 APPllOVU> OMB NO. 31~104 EXPIRES: "8/31186 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION

.., FACILITY NAME l1l . DOCKET NUMBER 12) LER NUMBER 131 PAGE 141 SEQUENTIAL REVISION YEAR NUMBER NUMBER PALISADES PLANT 0 5 0 0 0 2 5 59 3 - 0 1 4 Q 0 Q 3 . OF Q 4 CORRECTIVE ACTION The evaluation of cor,rective actions is ongoing and involves researching regulatory and industry design requirements for electrical penetrations, plant specific licensing commitments, design requirements specified by the penetration manufacturer, designs of similar electrical penetrations at other nuclear power plants, and contact with vendors of similar electrical penetrations. This research is complicated by the fact that the vendor of the Palisades el~ctrital pen~trati6ns (Viking) is no longer in business. Our initial assess~ent of the electrical penetratidn design requirements indicated that the nitrogen supply is important to maintaining the integrity of the electrical penetrations by reducing the potential for humidity induced corrosion of electrical conducting surfaces and contacts. Therefore, our preliminary conclusion is that the nitrogen supply should not be isolated.

The followin~ correcti~e actions have been .. developed to address this event:

1. Evaluate appropriate remedial corrective actions.to address the deficiencies in the electrical penetration design. *

2. Evaluate the ISi containment bounda~ies for the electrical penetr~tions in light of this design discrepancy. Revise containment isolation boundary tagging and containment leak rate testing prdcedures, as appropriate, based on this

• evaluation.

3. Issue updates to P&IOs, add valve numbers, "Q" list interpretations, and the Equipment Data Base for the north electrical penetration nitrogen purge system.

4. Evaluate the necessity of having a nitrogen purge continuously in the electrical

~enetr~tion. The evaluation should include the effects for inter~al corro~ion occurring after deletion of the riitrogen purge .

. 5. Provide a lessons learned memo to plant engineers emphasizing the evaluation of functional interfaces wh~n making changes to plant equipment.

OPERABILITY DETERMINATION

• The electrical penetrations ~re considered operable because the function of the penetrations as a barrier to containment leakage is maintained; however, the level of redundancy, in terms of the number of electrical penetration barriers, may be reduced under certain scenarios (e.g., earthquakei and tornados} due to the design deficiency.

The reduction in the level of redundancy is acceptable on an interim basis because: (1) the integrity of innermost barrier is maint~ined under all scenarios; (2) the barriers are periodically tested per 10CFRSO, Appendix J, to prove their functionality as a containment leakage barrier and; (3) the electrical penetrations have been operated and

~aintained in accordance with the manufacturer's requirements (i:e., with the space between the barriers filled with nitrogen).

cl NRC .Foim 3HA U.S. NUCLEAR REGULATORY COMMISSION

'- lf-831 APPROVED OMB NO. 31~104 EXPIRES: 8131186 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION FACILITY NAME 11'1 DOCKET NUMBER 121 lER NUMBER 131 PAGE 141 SEQUENTIAL REVISION YEAR NUMBER NUMBER PALISADES PLANT 0500025593_Q14_ 00 Q 4 OF Q 4 The operability requirements for the containment electrical penetration barriers are contained in Section 4.~ of the plant Technical Specifications. Section 4.5, "Containment Tests," addresses the requirements for local leakage te~t. The electrital penetration barriers have been shown to meet the acceptance c~iteria in this section.

Therefore, inter~m operation with the electrical penetration design .deficiency is authorized by the plant license.

ADDITIONAL INFORMATIO~

None