ML19323F081

Interim Deficiency Rept 3 Re Defective Inverters Mfg by Topaz Electronics & Supplied by Ge.Corrective Actions Under Review & Final Rept Should Be Forwarded by 800818

ML19323F081
Person / Time
Site:	Grand Gulf
Issue date:	05/15/1980
From:	MISSISSIPPI POWER & LIGHT CO.
To:
Shared Package
ML19323F077	List: ML19323F076 ML19323F081
References
NUDOCS 8005280505
Download: ML19323F081 (1)

Text

e O* Attachment to AECM-80/103 I

INTERIM REPORT #3, PRD-79/17 1

i I. Description of Deficiency This deficiency concerns the failure of inverters supplied by Topaz Electronics. They are used to supply essential divisional power ,

from the station batteries to the ECCS transmitter / trip unit analog ,

s'ensors. The failure is associated with transient disturbances such as those generated on the 125 VDC bus from switching relay coils. Blown fuses and failed SCR's have occurred as a result of the transient. The affetted model, designated GZ, is used in Grand Gulf Units 1 and 2.

.II. Safety Implications At Grand Gulf, failure of these inverters could impair or prevent i

the functioning of the emergency core cooling system, and thus, represents the potential for adverse effects on plant safety. For this reason this condition is judged reportable under 10 CFR 50.55(e).

III. Corrective Actions The complete corrective action plan is as yet unresolved. General Electric has proposed modifications to the inverters that will correct this deficiency. The modification consists of the installation of protective filtering devices on the inverter input. This modification is currently under evaluation. This deficiency is being tracked under MP&L PRD-79/17. We expect to provide a final report, including approved corrective actions, no later than August 18, 1980.

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