Information Notice 1997-45, Environmental Qualification Deficiency for Cables & Containment Penetration Pigtails

Environmental Qualification Deficiency for Cables & Containment Penetration Pigtails

ML031050410
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:	07/02/1997
From:	Slosson M Office of Nuclear Reactor Regulation
To:
References
IN-97-045, NUDOCS 9706260302
Download: ML031050410 (7)

UNITED SiATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001 July 2, 1997 NRC INFORMATION NOTICE 97-45: ENVIRONMENTAL QUALIFICATION DEFICIENCY

FOR CABLES AND CONTAINMENT PENETRATION

PIGTAILS

Addressees

All holders of operating licenses or construction permits for nuclear power reactors.

Puroose

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

addressees to a potential environmental qualification (EQ) deficiency for cables and

containment penetration pigtails. It is expected that recipients will review the information for

applicability to their facilities and consider actions, as appropriate to avoid similar problems.

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

While investigating high-range radiation monitor (HRRM) output fluctuations, Southern

California Edison (the licensee for the San Onofre plant) noted that the monitor output

appeared to be affected by environmental factors (temperature, air flow, electronic noise, and

so on). Accordingly, Southern California Edison initiated additional EQ testing to reassess

the environmental qualification of the HRRMs and signal cables. HRRMs provide information

to assist plant operators in diagnosing and responding to events.

For the EQ reassessment testing, Southern California Edison conducted stedm chamber tests

for the Rockbestos RSS-6-104/LE coaxial cable and the Amphenol (N) style connector

combination used for the HRRMs. On June 11, 1996, Southern California Edison concluded

that moisture could permeate the HRRM coaxial cable jacket during an accident and cause

partial shorting of the monitor signal at the penetration pigtail connectors. Because of the

extremely small signal current output from the HRRMs (nominally, pico-amperes), this partial

shorting of the signal would be sufficient to cause the HRRMs to be inoperable.

Based on the results obtained from additional testing, Southern California Edison replaced

the organically insulated cable and penetration pigtails inside containment at San Onofre

Unit 2 with stainless steel jacketed, mineral insulated cable and solid conductor containment

electrical penetrations. Testing of the new equipment configuration confirmed that EQ

requirements for this application were satisfied. Similar repairs for San Onofre Unit 3 will be

completed during its Cycle 9 refueling outage.

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IN 97-45 July 2, 1997 Discussion

In Licensee Event Report (LER) Number 96-005-01 (Accession No. 9702130104), Southern

California Edison indicates that lack of integrated testing of the system as a whole may have

contributed to the above-described EQ deficiency. During initial plant licensing, EQ testing

for the HRRMs, signal cables, and terminating connectors was performed on the discrete

components and each discrete component satisfied its specific EQ acceptance criterion

(insulating integrity).

The geometric configuration of cable/connector/penetration assembly combinations used to

connect HRRMs may also contribute to potential environmentally induced failures. At

San Onofre, the cable runs for the four HRRMs (two in each unit) vary from 175 to 250 feet

inside containment. Ot this length, a maximum of 90 feet is exposed in cable trays, with the

remaining cable routed through unsealed conduit. The HRRMs are installed at a 45-foot

higher elevation than the containment penetration assemblies (Westinghouse Model

WX-32916). As indicated in the above LER, during a loss-of-coolant accident and after

permeating the cable jacket, moisture could form a water column inside the cable jacket and

be forced into the containment penetration connector by the 45-foot pressure head developed

by the cable elevation change. Further, the containment penetration assembly pigtails

themselves use a cable similar to the HRRM cables. In discussions with the licensee

regarding the similarities between the Rockbestos coaxial cable and the containment

penetration pigtail cable, the licensee indicated that the jackets for both cables are identical

in construction, thickness, and material. The jacket material for both cables is radiation

cross-linked flame retardant non-corrosive modified polyolefin. In addition, the shield material

underneath the jackets of both cables is very similar and the shield construction is the same.

Thus, moisture could similarly permeate their jackets and short circuit the containment pigtail

connector. This partial shorting of the circuit could result in the loss of the HRRM function.

In addition to HRRM circuits, the above mentioned cables may be used in other monitoring

system applications. Further, the above mentioned penetration pigtails may also be used in

other safety-related equipment applications. Failure or degradation of these items during or

following design-basis accidents could significantly affect the functional performance of

safety-related equipaiert.

In Information Notice 93-33, "Potential Deficiency of Certain Class 1E Instrumentation and

Control Cables," dated April 28, 1993, the NRC staff noted that the insulation resistance of

the Rockbestos coaxial cables may be too low to meet specifications for use in General

Atomics radiation monitor circuits, depending on the environment to which the cable will be

exposed. The low insulation resistance of these Rockbestos coaxial cables was the subject

of a 10 CFR Part 21, "Reporting of Defects and Noncompliance," notification by General

Atomics dated March 28, 1989.

- IN 97-45 July 2, 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.

Mary e M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Duc T. Nguyen, NRR

301-41 o-3202 E-mail: dtnlnrc.gov

Frank S. Ashe, NRR

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

T. Jerrell Carter, NRR

301-415-1153 E-mail: tjc@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

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Attachment

IN 97-45 July 2, 1997 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

97-44 Failures of Gamma 07/01/97 All holders of OLs or CPs

Metrics Wide-Range for test and research

Linear Neutron Flux reactors

Channels

97-43 License Condition 07/01/97 All holders of OLs or CPs

Compliance for nuclear power reactors

97-42 Management Weaknesses 06/27/97 All fuel cycle conversion, Resulting in Failure enrichment, and fabrication

to Comply with Shipping facilities

Requirements for Special

Nuclear Material

97-41 Potentially Undersized 06/27/97 All holders of OLs or CPs

Emergency Diesel Generator for boiling-water reactors

Oil Coolers

97-40 Potential Nitrogen 06/26/97 All holders of OLs or CPs

Accumulation Resulting for pressurized-water

from Backleakage from reactors

Safety Injection Tanks

97-39 Inadequate 10 CFR 72.48 06/26/97 All holders of OLs or CPs

Safety Evaluations of for nuclear power reactors.

Independent Spent Fuel All holders of licenses for

Storage Installations independent spent fuel

storage installations

97-38 Level-Sensing System 06/24/97 All holders of OLs or CPs

Initiates Common-Mode for nuclear power reactors

Failure of High-Pressure- Injection Pumps

OL = Operating License

CP = Construction Permit

IN 97-45 July 2, 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.

original signed by S.H. Weiss for

Marylee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Duc T. Nguyen, NRR

301-415-3202 E-mail: dtnlnrc.gov

Frank S. Ashe, NRR

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

T. Jerrell Carter, NRR

301-415-1153 E-mail: tjc@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

TECH EDITOR'S COMMENTS INCORPORATED: 06/09/97 DISKIDOCUMENT NAME: 97-45.IN

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JTCarter __Is___.

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06/11/97 l _ 06/18/97 OFFICIAL RECORD COPY

IN 97- July , 1997 Page 3 of

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.

Marylee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Duc T. Nguyen, NRR

301-415-3202 E-mail: dtnlnrc.gov

Frank S. Ashe, NRR

301415-2785 E-mail: fsaenrc.gov

T. Jerrell Carter, NRR

301415-1153 E-mail: tjc@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

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OFC EELB:DE* EELB:DE* SC:EELB:DE ELB:DE* LB:DE*

NAME DTNguyen FSAshe DFThatcher PSGII l JACalvo

DATE 06/11/97 06/11/97 l 06/12/97 06/12/97 06/12/97 =

OFC DD:DE* I D:DE* I PECB:DRPM* I C:PECB:DRPM* AD:DRPM

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U11-11-11LAAL RECORD COPT

IN 97-xx insulation resistance of these Rockbestos coaxial cables was the subject of a

10 CFR Part 21, "Reporting of Defects and Noncompliance," notification by

General Atomics dated March 28, 1989.

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.

Marylee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical Contacts: Duc T. Nguyen, NRR

(301) 415-3202 E-mail: dtn1@nrc.gov

Frank S. Ashe, NRR

(301) 415-2785 E-mail: fsa~nrc.gov

T. Jerrell Carter, NRR

(301) 415-1153 E-mail: tjc~nrc.gov

Attachment: List of Recently Issued NRC Information Notices

DISTRIBUTION

File Center/NUDOCS EELB R/F

TECH EDITOR'S COMMENTS INCORPORATED: 06/09/97 DISK/DOCUMENT NAME: G:\SHARED\EQIN

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