Information Notice 1998-21, Potential Deficiency of Electrical Cable/Connection Systems

Potential Deficiency of Electrical Cable/Connection Systems

ML031050145
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	06/04/1998
From:	Roe J Office of Nuclear Reactor Regulation
To:
References
IN-98-021, NUDOCS 9805290266
Download: ML031050145 (11)

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'J_1 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001 June 4, 1998 NRC INFORMATION NOTICE 98-21: POTENTIAL DEFICIENCY OF ELECTRICAL

CABLEICONNECTION SYSTEMS

Addressees

All holders of operating licenses for nuclear power reactors, except those licensees who have

permanently ceased operations and have certified that fuel has been permanently removed

from the reactor vessel.

Purose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this Information notice to alert

addressees to a potential deficiency relating to environmental qualification of electrical

cable/connection systems. It is expected that recipients will review the information for

applicability to their facilities and consider actions, as appropriate. However, suggestions

contained in this information notice are not NRC requirements; therefore, no specific action or

written response to this notice is required.

Description of Circumstances

Sandia National Laboratories (SNL), under contract to NRC, tested electrical cable connections

to assess their accident performance If they were aged more slowly (i.e., at lower temperatures

and radiation dose rates) than in typical industry qualification tests and to investigate the

performance of connections aged to a nominal 60-year life. The results of this testing are

contained in the report NUREG/CR-6412, "Aging and Loss-of-Coolant Accident (LOCA) Testing

of Electrical Connections," January 1998 (Accession Number 9803180097). Electrical

connection test specimens consisting of conduit seals, connectors, and splices were chosen on

the basis of their usage In commercial nuclear power plants. The test program generally

followed the guidance provided In the Institute of Electrical and Electronics Engineers (IEEE)

Standard 323-1974, "IEEE Standard for Qualifying Class 1E Equipment for Nuclear Power

Generating Stations," and IEEE Standard 383-1974, "IEEE Standard for Type Test of Class IE

Electric Cables, Field Splices, and Connections for Nuclear Power Generating Stations.*

Test program specimens consisted of 10 different electrical connection types: three types of

conduit seals, two types of cable-to-device connectors, three types of cable-to-cable

connectors, and two types of In-line splices. Environmental exposure for the test specimens

consisted of two phases. The first phase consisted of simultaneous thermal and radiation

R

980129 P6 o

IN 98-21 June 4, 1998 aging for 6 months at 99 OC (210 OF) and a total radiation dose of 200 kGy (20 Mrad) at a dose

rate of 45.6 Gy/hr (4.56 krad/hr); the thermal exposure is equivalent to 60 years at 55 OC (131

'F) for an activation energy of 1.15 eV. The subsequent phase was a LOCA simulation that

consisted of an accident irradiation exposure at a dose rate of 3 kGy/hr (300 kradlhr) for an

accident dose of 1,000 kGy (100 Mrad) sequentially followed by a simulated accident steam

exposure. The simulated accident steam exposure test profile generally followed the typical

test profile contained in IEEE Standard 323-1974. During the simulated steam exposure test, the connections were energized at approximately 110 Vdc, 0 mA, to allow for online

measurement of insulation resistance (IR). Following the steam exposure test, which did not

include chemical spray, SNL performed several types of electrical measurements. Post-steam

exposure measurements performed on the test specimens included dry IR, submerged IR, dry

alternating current (ac) dielectric withstand, and submerged ac dielectric withstand.

Five of the 10 cable connection types did not pass a post-LOCA, submerged, ac dielectric

withstand test. These types were the Conax Buffalo, Rosemount, Patel/EGS quick disconnect, Amphenol coaxial, and Litton-VEAM. In addition, all of the Conax Buffalo electrical conduit seal

assembly cable connection conductors and approximately half of the Litton-VEAM connector

and the Amphenol coaxial cable connection conductors did not pass a dry ac dielectric

withstand test. The Conax Buffalo conduit seal assembly conductors had low IR values and the

two non-grounded conductors repeatedly blew 1-ampere fuses when energized at 110 Vdc.

Approximately one-third of the Lftton-VEAM connector and all four Amphenol coaxial cable

connector conductors had IR values below 107 ohms. The list of electrical cable connection

types included in the test program and the test results from the NUREGICR-6412 report are

provided in Attachment 1.

SNL has performed similar testing of electrical cables to determine the minimum insulation

thickness necessary for cable functional performance and long-term aging degradation of

cables. Results from these testing programs were provided In NRC Information Notice (IN) 92-

81, 'Potential Deficiency of Electrical Cables with Bonded Hypalon Jackets," dated December

11, 1992, and IN 93-33, "Potential Deficiency of Certain Class 1E Instrumentation and Control

Cables," dated April 28, 1993.

Discussion

The SNL test results provided in NUREGICR-6412 raised potential Issues relating to the long- term environmental qualification of electrical cable/connections that did not pass a dry ac

dielectric withstand test, a submerged ac dielectric withstand test, or exhibited very low or

marginal IR values. The staff reviewed the test data contained in the report and noted that

some of the tested cable/connections exhibited low or marginal IR values as early as 3 days

after the start of the simulated LOCA test exposure. It was also noted that Rockbestos Firewall

Ill cross-linked polyethylene multiconductor and Rockbestos coaxial cables were Installed by

SNL on connection test specimens that were supplied to SNL without a length of cable.

IN 98-21 June 4, 1998 Using these two nuclear-qualified cable types that were previously tested to the equivalent of 60

years helped to ensure that the testing isolated the effects of aging on the cable connections.

The aging research study sponsored by the NRC and performed by SNL Included searches of

licensee event reports (LERs) to Identify and review those LERs that contained Information

relating to cable connection aging. The results of these searches and reviews are provided in

NUREG/CR-5461, Aging of Cables, Connections, and Electrical Penetration Assemblies Used

in Nuclear Power Plants." In NUREG/CR-5461, SNL reported that electrical cable connections

are highly reliable devices under normal plant operating conditions, and they exhibited no

evidence of significant increases in failure rate under normal operating conditions with aging.

However, NUREGICR-5461 also reports that many of the causes of failures of electrical cable

connections In accident conditions would not be detected during normal operations because of

the absence of high temperatures and humidities, and that the expected most important failure

mode is shorting or reduced electrical Isolation. These conclusions are consistent with the

recorded test data results obtained during the electrical cable connection testing In that there

was no significant degradation in the measured insulation resistances of the test specimens

during the aging and accident irradiation exposures.

In addition, NUREG/CR-6412 reports post-test examination results for the tested cable

connection specimens. One primary reported result is that the jackets of a large fraction of the

cables attached to the connections were cracked and would allow ingress of moisture Into the

cable, which could then migrate Into the connection. Specifically, the jackets of the EGS

conduit seal cables were not sealed. The jackets of the NAMCO EC 210 connector cables

were split open and extensively cracked. Jackets over the Kapton-Insulated conductors for the

Conax Buffalo conduit seal cables were not sealed. The jackets of the Okonite tape splice and

Litton-VEAM connector cables were split open and cracked all the way around. For the EGS

Grayboot connector cable, the jacket was split open and was also not sealed. Generally, the

main function of a cable jacket is to protect the insulation during Installation. The SNL test

results, however, indicate that cable jacket integrity may be important in preventing moisture

intrusion at connections. Another post-test examination result was that the behavior of the

Conax Buffalo conduct seal conductors was produced by degraded Kapton-Insulated cable

leads. Post-test examination results for the behavior of the Litton-VEAM connector revealed

that the O-ring seals were brittle and had experienced compression set, which thereby reduced

their sealing ability and allowed moisture to enter the connector body. No explanation for the

behavior of the Amphenol coaxial connector or the Rosemount 353C conduit seal was Identified

during the post-test examination. Reported results also Indicate that the test results for a

particular connection type should be evaluated while considering the specific application and

set of environmental conditions. However, In certain nuclear power plant circuit applications, degradation or failure of electrical cable/connection systems during and/or following

design-basis events can significantly affect the functional performance of safety-related

equipment.

y-I

IN98-21 June 4, 1998 This information notice requires no specific action or written response. Ifyou have any

questions about the Information In this notice, please contact one of the technical contacts listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

fa~k W. Roe, Acting Director

'-ision of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Frank S. Ashe, NRR

301-415-2785 E-mail: fsa@nrc.gov

Satish K. Aggarwal, RES

301-415-6005 E-mail: ska~nrc.gov

John R. Tappert, NRR

301-415-1167 E-mail: jrt@nrc.gov

Attachments:

1. "Tested Electrical Cable Connections and Reported Test Results"

2. List of Recently Issued NRC Information Notices r-- A-TMCd, ,4g V, 1p Lu d - J

- t

Tested Electrical Cable Connections and Reported Test Resuts

Electrical Connection Connection Type Number of Connection Number of Connection Number of Connection Type

Type Conductors that Type Conductors that Conductors with Insulation

Failed Submerged AC Failed Dry AC Dielectric Resistance Values Below

Dielectric Withstand Test Withstand Test 10' Ohms During Steam

Exoosure Test

Conax Buffalo Electrmc ConduitSeal 4 of 4 failed 4 of 4 failed 4 of 4 Conductor Seal Assembly

Patel/EGS Conduit Seal Conduit Seal passed passed passed

Rosemount 353C Conduit Conduit Seal 3 of 6 failed passed passed

Seal

Narnco EC210 Y2" Series Cable-to-Device passed passed passed

Connector

Patel/EGS Y2"Quick Cable-to-Device 5 of 6 failed passed passed

Disconnect Connector

Amphenol 82- Cable-to-Cable Connector 4 of 4 failed 2 of 4 failed 4 of 4

816/16100/34500 Coa.dal

Connector

EGS GB-I Grayboot Cable-to-Cable Connector passed passed passed

Connector

Litton-VEAM CIR0I/CIRO6 Cable-to-Cable Connector 6 of 6 failed 2 of 6 failed 2 of 6 Okonite T-95/No.35 Tape In-Line Splice passed passed passed

Splice .

Raycheem NPKC-3-31A In-Line Splice passed passed passed

Splice Kit

pa- - denotes no repod abnonalfles 0O 0 rt

0 M 0'0

COI.-

'0 cr

' Attachment 2 IN 98-21 June 4,1998 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

98-20 Problems with Emergencv 6/4/98 All holders of operatina licenses

preparedness Respiratory for nuclear power reactor;

Protection Programs non-power reactors;

all fuel cycle and material

licensees require to have an

NRC-approval emergency plan

98-19 Shaft Binding in General Electric 6/3/98 All holders of operating licenses

Type SBM Control Switches for nuclear power reactors

98-18 Recent Contamination Incidences 5/13/98 Part 35 Medical Licensees

Resulting from Failure to Perform

Adequate Surveys

98-17 Federal Bureau of Investigations 5/7/98 All U.S. Nuclear Regulatory

(FBI) Awareness of National Commission fuel cycle and power

Security Issues and Responses and non-power reactor licensees

(ANSIR) Program

98-16 Inadequate Operational Checks 4/30/98 All Industrial Radiography

of Alarm Ratemeters Licensees

98-15 Intergrity of Operator Licensing 4/20/98 All holder of operating licenses

Examinations for nuclear power reactors except

those that have permanently

ceased operations and have

certified that fuel has been

permanently removed from the

reactor vessel

98-14 Undocumented Changes to 4120/98 All holders of operating licenses

Non-Power Reactor Safety or construction permits for test

System Wiring research reactors

OL = Operating License

CP = Construction Permit

IN 98-21 June 4, 1998 This information notice requires no specific action or written response. If you have any

questions about the information in this notice, please contact one of the technical contacts listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Frank S. Ashe, NRR

301-415-2785 E-mail: fsainrc.gov

Satish K. Aggarwal, RES

301-415-6005 E-mail: ska@nrc.gov

John R. Tappert, NRR

301-415-1167 E-mail: jrt@nrc.gov

Attachments:

1. "Tested Electrical Cable Connections and Reported Test Results"

2. List of Recently Issued NRC Information Notices

Document name: S:\DRPMSEC\98-21.IN

• SEE PREVIOUS CONCURRENCES

To receive copy, indicate: "C"= Copy w/o attachment; "A" = Copy w/attachment; "N" = None.

NO MARK = NO COPY!

OFC_[ EELE }EMMEBE SJ SCEE:DE]IIEfMEB:RESf SECY:EELB:DE

NAME JSKAggarwal

• • FAshe:ahc *PSGill *DFThatcher *MEMayfeld i

DATE 1l07 j10/08197 10107197 10107197 1010W97 051 98 OFC IC:EELB:DE l AD:DE PECB:DRPM l S:PECB Cl PECB AD:DRPM Xl

NAME *JACalvo GCLainas' JRTapperr RLDennig* JStolz* JWRoe'

DATE 10/20/97 05105198 05/20/98 05/20/98 05122/98 05/28/98 OFFICIAL RECORD COPY

IN98-XX

May xx, 1998 This information notice requires no specific action or written response. If you have any

questions about the information in this notice, please contact one of the technical contacts listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Frank S. Ashe, NRR

301-415-2785 E-mail: fsa@nrc.gov

Satish K. Aggarwal, RES

301-415-6005 E-mail: ska~nrc.gov

John R. Tappert, NRR

301-415-1167 E-mail: jrt@nrc.gov

Attachments:

1. "Tested Electrical Cable Connections and Reported Test Results"

2. List of Recently Issued NRC Information Notices

Document name: G:\JRT\A20

• SEE PREVIOUS CONCURRENCES

To receive copy, indicate: "C" = Copy w/o attachment; A" = Copy w/attachment; "N" = None.

NO MARK= NO COPYI

OFC

NAME

DATE

EELB:DE

FSAshe:ahc

10106/97 EMMEB:RES

SKAggarwal

10/08197 SC:EELB:DE

• PSGiII

10/07/97 SC:EELB:DE

DFThatcher

10107/97 l

_

C:EMMEB:RES

MEMayfeld

10/08197 I SECY:EELB:DE

051 /98 OFC C:EELB:DE AD:DE PECB:DRPM l SC:PECB lI 1l[

NAME IJACalvo GCLainaL JRTappert* RLDennig Ij

DATE 10/20197 05105198 05120/98 05/20/98 0a8 O\8

05 OFFICIAL RECORD COPY

IN 98-XX

May xx, 1998 This information notice requires no specific action or written response. If you have any

questions about the information in this notice, please contact one of the technical contacts listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Frank S. Ashe, NRR

301-415-2785 E-mail: fsainrc.gov

Satish K. Aggarwal, RES

301-415-6005 E-mail: ska@nrc.gov

John R. Tappert, NRR

301-415-1167 E-mail: jrt~nrc.gov

Attachments:

1. "Tested Electrical Cable Connections and Reported Test Results"

2. List of Recently Issued NRC Information Notices

Document name: G:\JRT\A20

• SEE PREVIOUS CONCURRENCES

To receive copy, indicate: "C" = Copy w/o attachment; "A" = Copy w/attachment; "N" = None.

NO MARK = NO COPY!

OFC EELB:DE EMMEB:RES SC:EELB: 1C:EELB:D l C:EMMEB:RES SECY:EELB:D

NAME *FSAshe:ahc *SKAggarwal *PSG111 *DFThatcher IMEMayfield

DATE 10/06/97 10/08197 10/07197 10107/97 10/08/97 051 /98 OFC

OC_ _

C.EELB.DE AD:DE I PECB:DRPM CPK 1 DDP

NAME *JACalvo GCLainas* JRTappert A nnig JWRoe

DATE 10/20/97 05105/98 0 98 / 98

. OFFICIA. RECORD COPY

IN 98-XX

XXX, 1998 This information notice requires no specific action or written response. If you have any

questions about the information in this notice, please contact one of the technical contacts

listed below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Frank S. Ashe, NRR

(301) 415-2785 E-Mail: fsa@nrc.gov

Satish K. Aggarwal, RES

(301) 415-6005 E-Mail: ska@nrc.gov

John R. Tappert, NRR

(301) 415-1167 E-Mail: jrt@nrc.gov

Attachments:

1. "Tested Electrical Cable Connections and Reported Test Results"

2. List of Recently Issued NRC Information Notices

Document name: G:\SHAREDA20

• SEE PREVIOUS CONCURRENCES

To receive copy, indicate: "C" = Copy w/o attachment; "A' = Copy w/attachment; "N" =

None. NO MARK = NO COPY!

fSKAggarwal

OFC EELB:DE EMMEB:RES SC:EELB:DE l SC:EELB:DE l C:EMMEB:RES SECY:EELB:DE

NAME FSAshe:ahc *PSGill j 1DFThatcher *MEMayfield l

DATE 10/06/97 10108/97 10/07/97 10/07/97 10108/97 l /98 OFC C:EELB:DE :DE \'5 PECB:DRPM l C:PECB:DRPM l AD:DRPM l

NAME 'JACalvo _ as JRTappert RLDennig JWRoe

DATE 10120197 =51 98 051 /98 051 /98 OFFICIAL RECORD COPY

IN 97-XX

XXX, 1997 This information notice requires no specific action or written response. If you have any questions

about the information in this notice, please contact one of the technical contacts listed below or

the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Frank S. Ashe, NRR

(301) 415-2785 E-Mail: fsaenrc.gov

Satish K Aggarwal, RES

(301) 415-6005 E-Mail: ska~nrc.gov

John R. Tappert, NRR

(301) 415-1167 E-Mail: jrt@nrc.gov

Attachments:

1. "Tested Electrical Cable Connections and Reported Test Results"

2. List of Recently Issued NRC Information Notices

Document Name: G:ISHAREDIA20-WPD

-

To receive copy. kidicate: "CE a CoDy wo attachment WA"= Coov wlattachment "N" = None. NO MARK = NO COPY1 OFFICE EELB:DE EMMEB:RES- C/EMMEB:RES 1SCEELB:DE SC/EELB:DE L4 NAME FSAshe:nkw M. e SKAggarwlA' MEMayfiell/o4 PGiII DFThatch5aV

DATE 106b/97 108 /97 10t)97 1_1

______ _0__ _7_97 OFFICE SECY/EELE IEB:DE ADDE l PECB:DRPM CPECB:DRPM

NAME JACalvo GCLainas JRTappert IRLDennig

DATE 10bz197 10/ /97 10/ /97 101 /97 11//97 OFFICE D/DRPM II 41

14 NAME

DATE

JRoe

10/ /97 too

OFFICIAL RECORD COPY