ML19344D119

Deficiency Rept SD-369/370-80-1:during testing,14 Relays & Trip Devices Did Not Meet Time Current Characteristic Specs of Relay for Application.Output sodium-cooled Reactors in Relays Found to Be Deficient & Will Be Replaced by 800601

ML19344D119
Person / Time
Site:	Mcguire, McGuire
Issue date:	02/29/1980
From:	DUKE POWER CO.
To:
Shared Package
ML19344D114	List: ML19344D112 ML19344D119
References
NUDOCS 8003110358
Download: ML19344D119 (2)

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. 7 MCGUIRE NUCLEAR STATION Report No: SD-369/370-80-1 Report Date: February 29, 1980 Fa(ility: McGuire Nuclear Station - Units 1 & 2 -

Identification of Deficiency: Solid State Protective Relays and Trip Devices-Deficient SCR's Description of Deficiency:

During relay and trip device acceptance and system startup testing, it was determined that fourteen (14) relays and trip devices did not meet the time-current characteristic specifications of the relay for its application (i.e.

the relay or device would trip at a lower level of current or time than its setting). The items found to contain the deficiency were solid state relays manufactured by Gould-Brown Boveri. Horsham, PA and consists of Types 1TE-51L and ITE-51Y overcurrent relays and Type SS4G (Power Shield) solid state trip device. The component that has been identified as causing the deficiency was Motorola, Inc. SCR's types 1379 and 1235. Additional Could-Brown Boveri relay types GR-5, ground fault relay, and Type 1TE-50, overcurrent relay also contain similar ty'pe SCR's. .

Preliminary investigations indicated that the output SCR in the relays was deficient. One ralay was returned to the manufacturer for investigation. The relay manufactuter and SCR manufacturer have evaluated and analyzed the deficiency and have indicated that the deficiency was caused by copper migration within the SCR. The copper migration was from the top metal system 1:,to the bulk silicon material which would result in its failure. The migration is a direct function of temperature and time. The deficiency is further described in a letter Jated February 11, 1960 to Mr. Victor Stello, Office of Inspection Enforcement, U.S.

Nuclear Regulatory Commissica, Washington, D. C. 20555, from Mr. D. D. Duval of Gould-Brown Boveri. However, the letter incorrectly identifies how and where the deficiencies were initially detected. The deficiencies were initially identified during testing at McGuW Nuclear Station rather than at Catawba Nuclear Station.

The manufacturer is conducting further evaluations to determine if the SCR defi-ciency is lot or batch related or purely random.

Analysis of Safety Implication:

There are 633 relays and trip devices within the station with 180 of these in safety circuits. Of the 633 relays only fourteen or approximately 2% have been found to have the deficiency. The deficiency appears to be random in nature.

Of the fourteen only five were in safety system circuits. Of these five, only two affected redundant circuits. The relays and trip devices are utilized for i overcurrent protection for various motors and load centers and upon failure of j the SCR would cause the associated load to be tripped.

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.-V Page Two Corrective Action:

All relays and trip devices containing the specific type of SCR's that are wishin safety circuits have been identified. The SCR's in the identified relays in Unit No. I will be replaced with SCR's that have gone through a special screening. The trip devices that do not have stud type SCR's will b~e' replaced rat.her than replacement of the SCR's. The SCR's that are re-moved will be returned to the manufacturer for further analysis and evalua-tion to determine if the deficiency is random or confined to a batch or lot.

Upon completion of this evaluation, action will be undertaken to changeout those SCR's and trip devices in Unit No. 2 as required to correct the deficiency. The change out of those items for Unit No. 1 is anticipated to be completed by June 1,1980. The changeout rf any SCR's and trip devices identifi<ed by the evaluation in Unit No. 2 is inticipated to be completed by January 1, 1981.

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