ML20034D512

Provides Early Notification of Emerging Issue Re Failures of Okonite Electrical Cables W/Bonded Hypalon Jacket During Tests Performed by Sandia Natl Labs.Info Notice Being Prepared to Alert Licensees to Potential Deficiency

ML20034D512
Person / Time
Issue date:	12/10/1992
From:	Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
To:	The Chairman NRC COMMISSION (OCM)
Shared Package
ML20034D513	List: ML20034D512 ML20035H052
References
NUDOCS 9212300263
Download: ML20034D512 (4)

Text

Enclosure r

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UNITED STATES

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NUCLEAR REGULATORY COMMISSION

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%.,yp,5 Cecemoer 10, '.992 MEMORANDUM FOR:

The Chairman Cc:raissioner Rogers Comissioner Curtiss Comissioner Remick Comissioner ce Planque James M. Taylor Executive Director for Operations FROM:

FAILURES OF OKONITE ELECTRICAL C JACKET DURING TESTS FERFORMED BY

SUBJECT:

LABORATORIES i

to the The ourcose of this memoranoum 1s to provid ing a f electrical caDies potential deficiency in the environmental qualification o with benced jackets.

ite electrical During testing conducted by Sanoia National Laboratories, O d a bonded Hypalon cables with ethylene propylene rueber (EPR) in i

accelerated aging d the cable insulation.

and did not survive the LOCA test.

to the interface be; ween the benced Hypalon jac i ulate 40 years s of plant life at of olant life at 69 *C (155 *F).ageo at DO *C (212 *F) for 5 52 *C (125 *F) passeo the LOCA test.

ffeo for a0 years of The Ckon1te Comoany had certifieo these cables to De cu piant life at 90 *C (194 *F).

insoections, the NRC has taken exception to the Okonite certo app alloweo the use of Okonite caoles for aoplications of upBased on t 71 *C (131 *F) for 40 years of plant life.

exists in the f i the staff is now concerned that a potential de ic encybonded-jacket ' cabl environmental qualification of these Okonite Hypalonter than 50 *C (1 they are used in environments with temperatures grea for forty years.

d Sandia on N staff met with representatives of the Okonite Company anSand Moncay, Novemoer 23, to discuss the validity of theAt the meeting, NUMARC was also represented.

tests of the same cable i

Okon1te's position.

verifieo that they have not performed qualificat onThey h a0 (194 *F) for insuiation and jacket materials for qualificatien to 90 *C useo by Sandia.

years.

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The Comissioners l interaction Ckonite stated that they have test data that show no chemicaOk exists between Hypalen and EPR.

However, the Sanoia results indicate a more ouickly than EPR insulation.

resulting from the emerittlement of the Okonite stated that Sanoia had applied a full accident ra mechanical failure of the insulatior, l

e dose before any thermal aging, whica in their opinion was extrem Hypaion.

i and also that Sandia overaged the cable during themal ag ng.

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by Samuel Moore have also failed during S These cables tor, twisted, shielded pair, 16 AWG d

(a type of were Oekoren Dekorad Type 1952, two-con uc instrument cables covered with ethylene-propy f Hypalon.

d to a 20-year Cne cable in which one conductor failed had bee d tors failed 133 *F).

These failures nad been thermally ageo to a 40-year life at 55 *C (ole in that the insulatio l

-ere similar to the f ailure of the Okonite-0ko on ca Eno bonced jacket hao split open.

h Qualification data reviewed by the staff for Samuel Moore d

The test caoles with bonded Hypalon jackets had been previously teste.d ca reports documented qualification of the Dekoron D lification Based on the Sandia test results, the staff has concerns that qua l

has not been establisheo for cables with bonded Hypa on f 50 *C (122 *F) installed service conditions exceeo environmental con Hypalon jackets for 40 years and that installed electrical cable with bencedTh ter than 50 *C, may be susceptible to f ailure.:efore 40 years if these caoles are u lifieo for up The staff is also concerned that other conded-jacket cables, qua oors, may be to 90 *C (194 *F) applications, as claimeo by various venThe difference susceptible to the same type of failures.

failure of between the jacket ano the insulation may be a factor f

nce.

jacketed configuration may not be representative of actu benced-jacket caoles.

i ately Data suoplied by Okonite indicate that their product is used Baseo on data collected by EPRI, Okonite cables a the installed caoles are 52 plants.

reactor containments of about 25 plants.these are all saf h

the same as those tested by Sandia.

l ted applications in many plants use other banced-jacket caole in safety-re a containment.

lied upon The Sanoia test results indicate that some components that are life of the power curing a LOCA may not remain functional fo there is no 4

plants.

immeciate safety concern because:

m 1

c The Commissioners

,i (2) the test results of east concern with caoles installed in containment;f safety-related cables in less than 40 would apply to a relatively small numoer o(3) caoles in containmei containment; years; (4) during plant operation EWR drywe tures (outside the the range of 57 *C to 66 *C and PWR containment tempera 5) the probabilitl reactor cavity) are in the range of 37 *C to 43 *C; (

5) there are l

large-creak LOCA is approximately 10' per reactor year; and i s equation.

uncertainties in estimating cable life using the Arrnen u in the process of While there is no immediate safety concern, the staff isthis potential defi 1ssuing an infomation notice to alert licensees to d consider Licensees would be expected to review the information notice an in safety-related appreorlate actions if they find bonded-jacket cables used Generic Letter acclications at temoeratures greater than 50 *C (122 *F).

" Environmental 58-07 ""coified Enforcement Policy Relating to 10 CFR 50.49.

l l

Power Jualification of Electrical Ecutcment Important to Safety for Nuc l

t ntial

1 ants" describes actions to be taken ey licensees wnen a po e 1

ceficiency in environmental qualification is identifiea.

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i The staff has discussed this concern with NUMARC and will be p h

ld be the written request to seek their assistance in t e re Among the near term (six months) actions expected of NUMAR bles are used in gathering of information to identify where bonded-jacket cai h they nuclear plants and the environmental conditions in ial j

conoition of the installed caDies.

If the results of the rear term actions confirm the validity of th l

a long term industry NUMARC would be recuestec to take the lead in ceve oping Baseo on monitoring and evaluation of for accitional generic

_regram to resolve the issue.

l NUMARC/inoustry actions. One staff will assess the need j

mmunications or staff actions.

be recognizeo that this While this memo cescribes plannea actions, it should j

ore is an evolving issue ano the describec actions may be changed a ft related information is obtainea on conced-jacket cables and their sa e y-acolications in nuclear plants. OriginaisignedW l

James E. Taylor r

James M. Taylor Executive Director for Operations DEDR ER cc:

SECY JSniezek JTW r

OGC 12/ /92 12(92 y

Distribution: See next page D

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TASK ACTION PLAN OUTLINE FOR BONDED-JACKET CABLES 4

1 TASKS' COMPLETED 1.

Met with Okonite. Sandia, and NUMARC at Headquarters.

Issued memorandum to Commission discussing potential deficiency.

2.

Issued Information Notice to notify licensees of the potential 3.

deficiency in environmental qualification of bonded-jacket cables.

Send letter to NUMARC to see if they were interested in assisting j

4.

industry in resolution of issue.

TASKS TO BE TAKEN and APPR0XIMATE SCHEDULES Review available bonded-jacket cable test data (Sandia and 1.

Qualification)

Scheduled Completion:

Ongoing Arrange meeting with NUMARC to discuss their involvement in resolution 2.

of issue.

Scheduled Completion:

January 29, 1993 Arrange meeting with NUMARC at Sandia to review the test data and view 3.

the test facilities.

Scheduled Completion:

February 24, 1993 f

Issue a TI for Regional inspection of cable environments and conditions.

4 Scheduled Completion:

July 15, 1993

• l Issue a Generic Letter (GL) requesting licensees provide information 5.

regarding the use of bonded-jacket cables, their qualification, and service conditions. Request response within 60-90 days.

Scheduled Completion:

October 15, 1993

• Review and evaluate information gathered by various methods discussed 6.

above. Determine long term safety significance and determine actions' needed for resolution of issue.6 months after receipt of information Scheduled Completion:

from industry action or GL

• Items 4 and 5 will be initiated; however, they may not be completed if i

NUMARC and industry actions are sufficient to allow determination and NOTE:

implementation of required actions (if needed) for resolution of issue.

t December 29, 1992 f

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-'/* M%,h UNITED STATES NUCLEAR REGULATORY COMMISSION f%e, i

.usmcTou. o, c. :osss 1sq.,i

,.f' 2ecemoer 22, 1992 Mr. William Rasin Vice cresident and Director Tecnnical Division Nuclear Management and Resources Council

.776 Eye Street, NW Suite 300 Wasnington, DC 20006-2496

Dear Mr. Rasin:

'he purpose of this letter is to notify you of a potential deficiency in the The environmental cualification of electrical cables with bonded jackets.

ncerns of the U.S. Nuclear Regulatory Commission (NRC) regarding the

uailfication of bonaec-jacket electrical caoles are ciscussea in NRC

nformation Notice (IN) 92-81. 'c ilure of Electrical Cables with Eoncea a

iypaion Jackets." wnich is enclosea.

as stated in the IN. the potential deficiency was identified as the result of On the basis testing conducteo for the NRC by Sanaia National Laboratories.

of test results for the electrical cables with Hypalo other bonded-jacket caoles in safety-related applications may be susceptib to failure when installed service conditions exceed temperatures of 50 "C (122' F) for 10 years.

it afety concern, the staff is ahile the NRC believes there is no immea a e s evaluating the extent of inis cotential deficiency and developing act

-ecessary to resolve inis 1ssue.means to gather 'nformation recu1 red to asc f

The information neecea includes:

3 ngnificance of this 1ssue.

conced-jacket cables oeing usea in safety-related applications; the environmental cualification status of these caoles; the actual se i

conoitions of the caoles:

~he NRC is notifying you of this potential deficiency and the initial NRC actions to aetermine if NUMARC is interested in being the focall l

naustry in resolving this issue.(1) coordinating the collection of informatio lled

.nere banced-jacket caDies are usea in nuclear plants and their insta inaustry by:

environmental conditions and (2) developing and coo

acket cables, s you are probably aware, mucn of the Sancia test cata that are Therefore, if NUMARC the IN and the NRC concerns have not yet been published.

a cecides to assist industry in the resolution of this issue,.we will notice a r

The meeting puolic meeting at Sanaia with NUMARC as the industry focal point.

ii be coserved, test would be held at Sana 1a so that the test f acil t es can I

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Cecemoer 22, _?92 t

Mr. William Rasin samoles and test data can be inspected, ano direct discussions c) i with the people who conoucted the testing.

l ti review the test data first hand, NUMARC and industry will be ab e to oc a n aj unoerstanding of the Sandia test activities and the significance of the tes results in order to better develop and coordinate an industry program to aodress the NRC's concerns with benced-jacket cables.

I If NUMARC is interested in assisting industry in the resolution of this is t ff at your earliest we would be happy to meet with you or memoers of your s l

etails on the staff's concerns relative to this matter.

If you have any questions regarcing this letter or need further inform George Hubbard at tnis issue, contact Conrad McCracken at (301) 504-2873 or i

I 201) 504-2870.

4 sincerely, l

C

/

William T. Russell Associate Director l

for Inspection and Tecnnical Assessment l

Office of Nuclear Reactor Regulation

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Enclosure:

As Stated i

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