ML19309E488

Notifies of Changes to Undervoltage Relaying for Protection Against Degraded Grid Voltage on 4160 Volt Safeguard Busses. Action Responds to NRC Request to Upgrade Circuitry Upon Review of Facility 790824 & 1012 & s

ML19309E488
Person / Time
Site:	Point Beach
Issue date:	04/17/1980
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
TAC-12955, TAC-12956, NUDOCS 8004220475
Download: ML19309E488 (2)

Text

O Wisconsin Electnc ecua couesur 231 W. MICHIGAN, P.O. BOX 2046. MILWAUKEE, WI $3201 April 17,1980 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D. C.

20555

Dear Mr. Denton:

DOCKET NOS. 50-266 AND 50-301 DEGRADED GRID VOLTAGE RELAYING POINT BEACH NUCLEAR PLANT UNITS 1 AND 2 After reviewing the additional informttion we provided in our letters dated August 24 and October 12, 1979 and January 17, 1980, we have been advised by members of your staff that the undervoltage protection relay circuitry at the Point Beach Nuclear Plant should be upgraded.

Specifically, we were told tnat undervoltage protection of a Class IE bus must be sensed from a signal from a Class IE bus.

Accordingly, we are proceeding with the following changes to the undervoltage relaying for protection against degraded grid voltage on the 4160 voit safeguard busses (1-A05, 1-A06, 2-A05 and 2-A06):

1.

Three new undervoltage relays will be installed on each safeguards bus.

These relays will te of a tyce which allows continucus acjust-cent of tae trip voltage.

2.

These relays will be connected to provice 2 of 3 logic in two separate actuation trains.

3.

An adjustable time delay will be provided, either in the undervoltage relays themselves, or in separate time delay relays.

4.

The relays will be physically located on the safeguards busses which they protect.

5.

Each set of three relays will provide the same function as the single relay presently located on the non-safeguards bus which protects against cegraded grid voltage.

Ys4 tl 8004220 W

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Mr. Harold R. Denton, Director April 17,1980 The actual trip settings and time delays settings will be provided to you at a later date as a modification to our pending Technical Specification Change Request No. 45 dated July 28, 1977. Should you have any questions con-cerning this plant modification, please contact us.

Very truly yours, C. W. Fay, Director i

Nuclear Power Department 1

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