ML19350A174
| ML19350A174 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 12/03/1977 |
| From: | Case E Office of Nuclear Reactor Regulation |
| To: | Switzer D CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| IEB-77-06, IEB-77-6, NUDOCS 8102180797 | |
| Download: ML19350A174 (2) | |
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3 y'3, ' 'g NUCLEAR REGULATORY COMMisslON E
WASHING TON. O. C. 20555 l
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December 3, 1977 Docket No. 50-21'3 Connecticut Yankee Atomic Power Company
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ATTH:
Mr. Donald C. Switzer, President Post Office Box 270 Hartford, Connecticut 06101 Gentlemen:
On or about November 22, 1977, you should have received IE Bulletin No. 77-06 on Containment Electrical Penetrationsfrom the Regional Office of the NRC Office of Inspection and Enforcement (copy enclosed).
This Bulletin requests that you provide information on whether your Haddam Neck Plant utilizes containment electrical penetrations that depend on an epoxy sealant and a dry nitrogen environpient to ensure functional capabil ity.
Due to the safety significance of this matter, the staff also conducted a telephone survey of all operating plants to obtain preliminary infor-mation on the adequacy of qualification testing of containr,mnt electrical penetrations.
Based on our discussions with your staff, it was determined that additional documentation (e.g., test reports, analyses) is required to establish the extent of environmental qualification applicable to the penetration-assemblies at the Haddam Neck Plant.
Therefore, pursuant to 10 CFR 50.54(f) of the Commission's regulations, you are hereby requested to deliver to the Office of Nuclear Reactor Regulation, Nuclear Regulatory Coninission, Washington, D.C.
20555, not later than December 12, 1977, information which establishes the required environmental qualification of the penetrations used in your facility.
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t Connecticut Yankee Atomic Power December 3,1977 Company If you a're not able to provide complete documentation of the required environmental qualification of all applicable connectors, you should submit plans and programs for qualifying existing equipment or plans for replacing unqualified penetrations with qualified equipment.
In this case, you must also include with your response a justification
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that continued operation of the facility, for whatever period it will take to environmentally qualify the penetrations in accordance with NRC regulations, would not create undue risk to the health and safety of the public.
Please advise us if you have any questions relative to this matter.
Sinc,e.c ly, pl
,j. k b-Edson G. Case'. Acting Director
[ Office of, Nuclear Reactor Regulation
Enclosure:
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Connecticut Yankee Atomic Power Company Deu L W cc: Day, Berry A Howard Coupsflors at Law One Constitution Plaza Hartford, Connecticut 05103 Russell Library 1
119 Broad Street Middletown, Connecticut 16457 Superintendent Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 e
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L f:UCLEAR REGULAT0i'Y CTIISSIC:;
0FFICE FO.1 I :Si'ECTIO:: A:l0 E::!0RC".E::T 1lA5ttii;GTO:;, D. C.
20555 floverber 22, 1977 IE Bulletin i;. 77-06 POTEl:TIAL PROBLE:15 WITH CO:;1Ali;"EllT ELECTRICAL PE.EMTIO !.ASSE:
15 LIES Description of Circumstances:
On October 3, 1977,*;orthcast i;uclear Energy Co.pany r'eported to the I;RC Pegicn 1 OTfice that tua control valves instelled inside centtir.mr.t at Ilillstone Unit !!c. 2 d:: cons;cated abnorcal operational chcracteristics.
The licensee reported that an unexpect:d closure cf a letdcun flo.: stop valve occurrcd.
L'hile investigating this prcble-', the nornally closed safety injection recirculation return 1jn,e drain valve was found to be in the open position.
Investigatien of these ever.ts revealed the cause for failure to be electrical shorts between conductors within a contain-ment low voltage penetration assembly.
The licensee subse;uently determined that the wiring for both of the valves shared the same low voltage codule in an eiectrical penetration.
Electrical tests by the licensee revealed that 15 of the 85 conducters in the suspect connector nodule exhibited decreased insulatica resistar.cc bet.een cenductors.
Based on this finding, it is believed that an clec-trical path bet.een adjacent circuits in the connector nodule was established.
This resulted in spurious operation cf the vcives.
Sinilar resistance chechs nerforce:i t 1 the remaining leu voltage modules witt.in the affected penetration esst..;bly revcaled 17 additional conductors with reduced insulation resistcqces.
All ccnductors with resistarces less than 20 negchrs were disconnected and their circuits were reconnccted through spare conductort.
Exemination of the three renaining low voltage penetration asse.blics, identified ~/ a6ditional conductors with resistcnces of less than 20 megohns.
Each of these circuits were also reconnected through a sp;re conductor.
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.t IE Bulletin !!o. 77-06 l'ove:.Qcr 22, 1977 InvestitItion shy. led thL tha reduced insulatic, resister.c2 u.s pecbsl.-
ccused by r.uicture accu nie tion uithin the pt: ctrcticn csst.11y.:::... r uith smcil fissurcs in the epoxy seals surroanding cach cce,ductcr in the rodule.
The licensae t:elieves that r.3istuer. penetrning these cracks reduced the insulation rcsistance between adjrcant conductors.
To pnvent further degra ation from coisture buildup within the penetrction csst"biies, d
the licensee re-established a dry nitrogen pressure of 24 PSIG in the penetrations.
Subsequently the licensee reported that a second event of a similar nature occurred on October 14, 1977.
In this inst:nce the sample iso-lation valve for the pressurizer surae line failed to cicsc en cer and.
Investigt tion into this event indicated that clectrical shorts i ct'.-:eca conductors due to a noisture accu.:ulation probicn was the prcN.Lic ccuse for valve miscperation.
The charted uires ucre disconnected and the valve was dt-energized in the closed position.
In discussions on the issue with the licensee and the electricci penetration vendor, General Electric Ccmpany, ::?.C stcff deternined th:2 maintenance of nitrogen pressure is essential to the integrity of both high and low voltage penetration assenolies. The General Electric Company specifies in its penetration cssea:bly raintenance and operetien manual that a 15 PSIG dry nitrogen pressure should be raintaircd on leu voltage units while 30 PSIG should be maintained on high voltage units.
Action To Be Taken By Licensees Of All Power P,ecctor Facilities Uith An Operating License:
Containment Electrical Penetrations - For safety related systems 1.0 Do you have containment electrical penetrations that are of the G. E. Series 100, or are othcruise similar in that they depend upon an epoxy ssalent and a dry nitrocen pressure envircrr.cnt to ensure that the electrical and pressure characteristics are raintained so as to ensure the functioncl capability as required by the plant's safety analysis report; nately, (1) to ensure adequate fuactioning of electrical scfety-relatcd equipecnt and (2) to ensure containtant leak tightness?
1.1 Have you experienced any electrical failures with'this type of penetration?
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IE Culletin i:o. 77-06 i;ove R r 22, IP77 s
5 2.0 Por the:c p;r..trction; references N Ms; I c.'.t.e, t ve ecintained the nenufacturce's pr:.::rit:e ni;r..:n pa:.r-all tires':
2.1 If you hav.> 0;ercted the penetret. u....:.:. :: i r t. :-
nitreccn pr.:ssura :.z!. tr.y dc;raca; wn cf ins':!cti.c rc>i.c.z ce er cncrolou:- co pon;nt c;'Orctica Cctc;ied?
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2.2 If no r ccsurc:.cnts t ere tchca curing periods :: hen nitrega pressure 1:tt, not raittained, he.: t:cre yev ass. ced thn tr.:
insulation resistance 1:as not degrcding or degraded?
2.3 Hou c'o you c'cter :ine t'.'t circuit insulation resista.:cs vel..ts are satisfactorily raintained?
3.0 Is th:re e nesd, cs dettmined by either the vcedor er y;urself, to r.aintcin penetratier.s pressurized.durinc a LCCA?
3.1 F: hat reasures have yc.u takcn to ensure that penetratic:n of this type t.ill perforra their design function ender LOCA conditions?
(design revie-ts, analyses or tests) 3.2 Are thc reasures thet provide t'1is cssurance cdecuate to sctisfy the Ccmissicn's regulations (GDC 4,'Appendi A to Part'50; QA Criteria, l.pcendix D to Part 50) 4.0 Provide your response to Itcins 1.0 through 3.2 above in s.riting uithin 10 c.'ays.
In addition, provide an crc' respcnse b./ 4:00 p.~.
(Local Tire) :;ove:.ter 25, 1977.
Ecsponses sterld be s ' ;itted to the Cirector of th2 cpp?cpricte ;."C Region:.i Cffice.
'. c: py o f s ritten resrenses should he fen:ctded to the.'. S. ::ucle:r Ecc.*leter.,
Co lissicin, Cf fice of Inspectica cr.d Enforcc c.t, ~:ivit ica ei Reat. tor Operations Inspectien, ':cshingtoa, D. C.
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Approved by 07.0, B103225 (R2072); cle:rance expir-. 7-31-50. Acrevti tras given under e blcnket clearance specifically :.:r identified gcneric probicas.
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