Information Notice 1994-04, Digital Integrated Circuit Sockets with Intermittent Contact

Digital Integrated Circuit Sockets with Intermittent Contact

ML031070058
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:	01/14/1994
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-94-004, NUDOCS 9401100143
Download: ML031070058 (6)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 January 14, 1994 NRC INFORMATION NOTICE 94-04: DIGITAL INTEGRATED CIRCUIT SOCKETS WITH

INTERMITTENT

Addressees

All NRC licensees except licensed operators.

PurDose

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

notice to alert addressees to a potential problem involving socket connectors

used for digital integrated circuits manufactured by Augat, Inc. 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 is

required.

Description of Circumstances

During April 1993, at the D. C. Cook Nuclear Plant, the licensee observed

intermittent failures of various process control units during testing. The

internal monitoring system for a control unit would detect a problem and

the instrument down (i.e., cause its outputs to reduce to zero and remain shutin

an audible alarm state). The NRC learned about this recurrent problem during

an analog-to-digital process instrumentation inspection at this site (NRC

Inspection Report 50-315/93-18; 50-316/93-18). Subsequent to a July

meeting between the licensee and the control unit manufacturer, Asea 1, 1993, Brown

Boveri-Kent-Taylor (ABB-Kent-Taylor), the problem was isolated to the sockets

for the integrated circuits. Deficiencies in the sockets resulted in

intermittent contacts between the integrated circuits and the sockets, thus

interrupting signal processing. These sockets, which are manufactured by

Augat, Inc., are made in various grades and one of the lower grade sockets was

being used. Augat, Inc. is an international supplier of interconnection

systems for the computer, automotive, and telecommunications industries.

These sockets were produced in large numbers and some may be in use in nuclear

as well as non-nuclear applications where their failure could either initiate

a transient or interfere with response to a transient.

The process control units (Taylor MOD 30) were built as commercial-grade

equipment in 1989 but were not delivered to the licensee until 1992, and were

not shipped to the site until the Spring of 1993. The original purchase order

included both safety-related units and nonsafety-related units. Asea Brown

Boveri-Combustion Engineering (ABB-CE) was supposed to qualify the equipment

9401100143'

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\_JIN 94-04 January 14, 1994 designated for safety-related use before the safety-related equipment was

released and shipped to the D.C. Cook plant. For reasons unrelated to the

socket deficiencies, the contract was amended to exclude safety-related

equipment. However, the nonsafety-related equipment will be used in the AMSAC

[ATWS (anticipated transients without scram) Mitigation System Actuation

Circuitry].

The licensee informed ABB-CE of this potential generic product deficiency in

an August 20, 1993, letter. Followup in September 1993 revealed that the

manufacturer believes it has not sold any Taylor MOD 30 instruments to nuclear

power plants for use in safety-related applications.

Discussion

In the D. C. Cook application, the sockets are located on an internal

component identified as a 'digital board." There are 7 sockets per digital

board; 5 of the sockets are 28-pin sockets and are being used for programmed

PROMs (Programmable Read Only Memories), one 20-pin socket is being used for a

programmed logic array integrated circuit, and one 40-pin socket is being used

for a single-chip microprocessor unit. The 520 instruments contain a total of

more than 3500 sockets.

Subsequent discussions with the licensee concerning the generic nature of the

deficiency produced additional information. The 20-, 28-, and 40-pin sockets

had the following respective Augat part numbers: 520-AG12D-ES, 528-AG12D-ES,

540-AG12D-ES. The 'ES' suffix indicates that a socket is an Economy Series

socket. Augat, Inc. introduced this series in 1985 to provide a less

expensive version of its traditional machined contact. The contact portion of

the ES socket is produced by a stamping process rather than by a machining

process. The stamped ES sockets were first used in Taylor MOD 30 equipment in

1988. In February 1991, the control unit manufacturer, ABB-Kent-Taylor, changed back to the machined version after producing approximately 7,000-

10,000 instruments with the ES sockets. Tests performed in July 1993 confirmed that the withdrawal force for the ES stamped contact sockets was

considerably less than for the machined contact sockets. Both of these

sockets had a tin-lead inner contact. The ES sockets are being replaced with

machined contact 520-AG12D, 528-AG12D, and 540-AG12D sockets.

Some Augat, Inc. ES sockets have exhibited a relatively high incidence of

intermittent failure. The failure rate among the 256 Taylor MOD 30

instruments tested was determined to be approximately 15 percent through

July 1993. It appears that the use of a tin-lead inner contact, the stamping

method of manufacture, and the length of time an instrument sits de-energized

may serve in combination to permit or create oxidation on the contacts.

However, the root cause of the intermittent contact between the integrated

circuit and its socket has not been determined. ABB-Kent-Taylor believes that

the delay between shipment and construction, while the units sat de-energized, may have been a contributing factor in the failure. If this is the case, instruments stored as spare parts (which would also be de-energized) could be

similarly affected.

IN 94-04 January 14, 1994 A recent design review of an analog-to-digital upgrade for the reactor

protection system at a foreign plant revealed that the integrated circuit

socket specified was the type discussed above; i.e., it was

Augat, Inc. and was the ES type. The contact design is beingmanufactured by

reevaluated.

This information notice requires no specific action or written response.

you have any questions about the information in this notice, please If

contact

one of the technical contacts listed below or the appropriate Office of

Nuclear Reactor Regulation project manage

n K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: Edward R. Schweibinz, RIII

(708) 829-9712 Vern Hodge, NRR

(301) 504-1861 Attachment:

List of Recently Issued NRC Information Notices

.A- h-Atchment

IN 94-04 January 14, 1994 Page 1 of I

LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information ate of

Notice No. Subject Issuance

IssuaceIssued

Isued to

t

94-03 Deficiencies Identified 01/11/94 during Service Water System All holders of OLs or CPs

Operational Performance for nuclear power reactors.

Inspections

94-02 Inoperability of General 01/07/94 Electric Magne-Blast All holders of OLs or CPs

Breaker Because of Mis- for nuclear power reactors.

Alignment of Close-Latch

Spring

94-01 Turbine Blade Failures 01/07/94 All holders of OLs or CPs

Caused by Torsional for nuclear power reactors.

Excitation from Electrical

System Disturbance

93-101 Jet Pump Hold-Down Beam 12/17/93 Failure All holders of OLs or CPs

for boiling-water reactors.93-100 Reporting Requirements 12/22/93 for Bankruptcy All U.S. Nuclear Regulatory

Commission licensees.

91-29, Potential Deficiencies 12/22/93 Supp. 2 Found During Electrical All holders of OLs or CPs

Distribution System for nuclear power reactors.

Functional Inspections

93-99 Undervoltage Relay and 12/21/93 Thermal Overload Setpoint All holders of OLs and CPs

Problems for nuclear power reactors.

93-98 Motor Brakes on Valve 12/20/93 Actuator Motors All holders of OLs and CPs

for nuclear power reactors.

93-97 Failures of Yokes 12/17/93 Installed on Walworth All holders of OLs or CPs

Gate and Globe Valves for nuclear power reactors.

93-96 Improper Reset Causes 12/14/93 Emergency Diesel All holders of OLs or CPs

Generator Failures for nuclear power reactors.

OL

0 Operating License

CP = Construction Permit

<F~IN 94-04 il I . .

January 14, 1994 A recent design review of an analog-to-digital upgrade for the reactor

protection system at a foreign plant revealed that the integrated circuit

socket specified was the type discussed above; i.e., it was manufactured by

Augat, Inc. and was the ES type. The contact design is being reevaluated.

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 project manager.

°rfml agned '

Bnaln K.Grimes

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: Edward R. Schweibinz, RIII

(708) 829-9712 Vern Hodge, NRR

(301) 504-1861 Attachments:

1. List of Recently Issued NRC Information Notices

This information notice was coordinated with MBCongdon, OIP/PDD, on about

11/22/93.

This information notice was coordinated with EWBrach, NMSS/LLWM, on 12/22/93.

• SFF PREVIOUS CONCURRENCE

OFFICE *OGCB *TECH ED. *C:HICB/DSSA *REGION III

NAME CVHodge RSanders JSWermiel ERSchweibinz

DATE 11/18/93 11/16/93 1/18/93 Ž2101/93

_I II

I _ .

• D:DRP/REGION III *C:OGCB/NRR D: DM/lRX

EGGreenman GHMarcus A60Vs

12/01/93 12/02/93 101//0/94 DOCUMENT NAME: 94-04.IN

IN 93-xx

November xx, 1993 During a September 13-14, 1993, Digital System Reliability and Nuclear Safety

Workshop sponsored by the NRC in cooperation with the National Institute of

Standards and Technology, this subject was discussed with a foreign

participant. The following week that participant contacted the NRC for more

details, because a design review of an analog-to-digital upgrade for the

reactor protection system at the foreign plant revealed that the IC socket

specified was the type discussed above; i.e., it was manufactured by Augat, Inc. and was the ES type. Subsequently, the design has been reevaluated to

consider specification of a machined contact.

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 project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: Edward R. Schweibinz, Region III

(708) 829-9712 Vern Hodge, NRR

(301) 504-1861 Attachments:

1. List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

OFFICE *OGCB *TECH ED. *REGION III *Region *C:HICB/DSSA

III

NAME CVHodge RSanders ERSchweibinz EGGreenman JSWermiel

DATE 11/18/93. . 11/16/93

. 12/01/93

. . 12/01/93

. 11/18/93

. l

I D:DORS/NRR

C:OGCB/NRR

GHMarcus&

1a/2. /93 I BKGrimes

11/ /93 DOCUMENT NAME: ICSOCKET.INF