ML20038B958

Application for Amend to Licenses DPR-24 & DPR-27 Changing Time Delay Specified in Item 9 of Table 15.3.5-1 to Insure Emergency Power Undervoltage Relay Protection & Permit Start of Reactor Coolant Pump Motor in Cold Shutdown

ML20038B958
Person / Time
Site:	Point Beach
Issue date:	12/03/1981
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
TAC-47404, TAC-47405, NUDOCS 8112090362
Download: ML20038B958 (2)

Text

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lHsconsm Bectnc ma come i 231 W. MICHIGAN, P.O. BOX 2046. MILWAUKEE, WI 53201 i December 3, 1981

{ Q Ms 6 4 1 Mr. Harold R. Denton, Director / , ,

! Office of Nuclear Reactor Regulation / g=- g U. S. NUCLEAR REGULATORY COMMISSION E- -

I Washington, D. C. 20555 C DE09 1981* C Attention: Mr. Robert A. Clark, Chief khA v.s samump8 es a m 8 M  % 8 i Operating Reactors Branch 3 **

N ,

Gentlemen: N DOCKET NOS. 50-266 AND 50-301 -

EMERGENCY POWER UNDERVOLTAGE RELAY PROTECTION POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 i

On March 31, 1981 the Nuclear Regulatory Commission issued License Amendments 47 and 52 to Facility Operating Licenses DPR-24 and DPR-27, respectively, for the Point Beach Nuclear Plant, Units 1 and 2. These license amendments included changes to the Point Beach. Technical Specifications which specified undervoltage and time delay setpoints for replacement protective relaying to be installed, as an NRC-required modifi-cation, on the 4160-volt and 480-volt safeguards electrical buses. Although the amendments were issued as effective on the date of issue, full implementation of the Technical Specification was specified to be sixty days after the date of issue to permit the Licensee time to install the replacement relays.

In a letter dated May 30, 1981, we notified the NRC

that we would be unable to install the replacement undervoltage relays within the sixty-day implementation time frame because of unanticipated procurement delays. We stated that we would

.l "

notify the NRC when the modifications were completed and when j

the Technical Specification could be fully implemented as.

issued.

J Subsequently, the necessary undervoltage relays, Agastat time delay. relays and the required quality assurance documentation has been received at the plant and the relays installed on Point Beach, Unit 1. In attempting to start a reactor coolant pump in preparation for heatup of the reactor coolant system following a refueling shutdown, we found that, with this modified relaying installed, the time delay of 13.5 1

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8112090362 811203 PDR ADOCK 05000266 p PDR Sife i

, Mr. Harold R. Denton D;c mber 3, 1981 e

3 i

Sec +5% as specified in Table 15.3.5-1, Item No. 9, " Degraded Voltage (4.16KV)", is insufficient to permit starting the reactor coolant pump motor in the cold shutdown condition.

Starting the first reactor coolant pump requires approximately 17 seconds for the bus voltage, which is depressed during the starting transient to approximately 3640 volts, to recover to above the 3675 volt setting of the degraded voltage relay.

Starting the second pump requires a voltage recovery time of approximately 22.5 seconds, since the starting transient must permit overcoming the reverse flow in the idle loop. Accordingly, a modification to License Amendments 47 and 52 is necessary in order to permit our full compliance with these Technical Specifi-cation changes.

We hereby propose that the time delay specified in Item 9 of Table 15.3.5-1 be changed to read, " Time Delay: less than 60 seconds at 0-95% of voltage setting." The original purpose of this Specification was to establish a degraded grid voltage limit which would preclude long-term operation of safeguards motor loads at reduced voltage. Changing this time delay Specification will not affect the purpose of this protection.

By specifying a time delay of less than sixty seconds, we shall also be able to implement a sufficient time delay so that, in the event of a reactor coolant pump motor starting problem, the motor overcurrent protection, which has a 29 second time delay, will trip the reactor coolant pump motor off line before the bus degraded grid voltage relay disconnects the 4160 volt safeguards bus from offsite power. Please note that the separate relaying protection for loss of voltage, as specified in Item 10 of Table 15.3.5-1, is not affected by this time delay specification change.

Your very prompt action on this modification to License Amendments 47 and 52 is requested so that we may proceed with the Point Beach Unit 1 heatup and return to power. Please contact us at once if you have any questions concerning this situation.

Very truly yours,

/

C. W. Fay, Director Nuclear Power Department Copy to NRC Resident Inspector