ML17212B570

Forwards Request for Addl Info Re Degraded Grid Voltage Protection

ML17212B570
Person / Time
Site:	Saint Lucie
Issue date:	04/19/1982
From:	Clark R Office of Nuclear Reactor Regulation
To:	Robert E. Uhrig FLORIDA POWER & LIGHT CO.
References
NUDOCS 8205060166
Download: ML17212B570 (6)

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APR 19 'l982 DISTRIBUTION:

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Docket No, 50-335 Dr. Robert E. Uhrig Vice President Advanced Systems

& Technology Florida Power 8'.Light Company P,

O. Box 529100 Miami, Florida 33152

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+'ear Dr. Uhrig:

He have reviewed your letter of flarch 18, 1982, (L-82-105).regarding degraded grid voltage protection and have determined that additional information is necessary to complete our review.

You are requested to provide the information identified jn the enclosure within 30 days of receipt of this letter, Tgie reporting and/or recordkeeping requirements contained in this ~letter affect fewer than ten respondents; therefore, ONB clearance is not required under

}P,. L. 9G<<511.

tte want to complete this issue by September 30, 5'982. If you desire we will be glad to meet and discuss this info@nation with you.

Sincerely, Origina I signed by Q<yl~ g. Trammel,III ~y-Robert A. Clark, Chief Operating Reactors Branch i'3 Division of Licensing

Enclosure:

As stated cc; See next page hL ORBP'$ B!'DSI OFFICE)

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.PsDP ADOCY. 05,000335 OF I. 205060l66,8204l9 FIClAL RECORD COPY USQPO: 1981-33&960

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/1 Florida Power

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CC:

Harold F. Reis, Esquire Lowenstein,

Newman, Reis 5 Alexrad 1025 Connecticut Avenue, N.W.

Washington, D. C; '0036 Norman A. Coll, Esquire McCarthy, Steel, Hector 8 Davis 14th Floor, First. National Bank Building Miami.Florida 33131-Indian River Junior College Library 3209.Virginia Avenue Fort Pierce, Florida 33450 Administrator Department of Environmental Regulation Power Plant SitingSection'..

~ State of Florida 2600 Blair Stone Road Tallahassee, Florida 32301 Mr. Weldon B. Lewis County Adminibtrator

'St. Lucie County 2300 Virginia Avenue, Room 104 Fort Pierce, Florida 33450 U.S. Environmental Protection Agency Region IV Office ATTN:

Regional Radiation Representative 345 Courtland Street; N.E.

Atlanta, Georgia 30308 Mr. Charles B. Brinkman

'anager'-

Washington Nuclear Operations C-E Power Systems

.Combustion Engineering, Inc.

4853 Cordell Avenue, Suite A-1 Bethesda; Maryland 20014 Regional Administrator Nuclear Regulatory Commission,. Region II Office of Executive Director for Operations 101 Marietta Street; Suiti 3100 Atlanta, Georgia 30303

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Mr. Jack Schreve Office 'of the Public Counsel

~ Room 4, Holland Building Tallahassee, Florida 32304 Resident Inspector c/o U.S.N.R.C.

7900 S; AIA Jensen. Beach,,Florida 33457 Bureau of Intergovernmental Relations 660 Apalachee Parkway Tallahassee, Florida 32304

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~ 0 CLOSURE REQUEST FOR ADDITIONAL INFORMATION ST. LUCIE, UNIT 1 DEGRADED GRID PROTECTION Ref. 1:

FP&L letter (U. E. Uhrig) to NRC (W. Gammill), dated November 9, 1979.

Ref. 2:

FP&L letter (U. E. Uhrig) to NRC (R. A. Clark),'ated July 3, 1980.

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Ref." 3:

FP&L letter--(U.. E. Uhrig) to NRC (D. Eisenhut),

dated September 12, 1980.

Ref. 4:

FP&L letter (U.'; Uhrig) to NRC (R. A. Clark), dated March 18, 1982.

Ref. 5:

NRC letter to FP&L; dated June 3, 1977.

Ref; 6:

FP&L letter (U. E. Uhrig) to NRC (D. Eisenhut),

dated February 10, 1981.

Ref. 7:

Telecons, R. Kamiskay, D. Smith, P'age (FP&L), C. Nelson and D. Prevatte (NRC), and J. Selan (LLNL), dated February 3, 1982 and February 23, 1982.

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NRC letter to FP&L, dated November 30, 1981.

j 1.

The undervoltage relay setpoints and associated time delays have been defined in Refs.

1 and 4 as the following:

(a)

The'V-2 (inverse time) relay on the 4 kV Class lE buses has a setpoint of 88.3% of 4160 volts (3673 volts) with a time dial setting of 1.

This setpoint is 91.8% of the nameplate rating of the 4000-volt motors.

(b)

The relay at the 480-volt load center-buses has a setpoint of 89.4% of 480 volts (429 volts) with a time delay of 1 second.

This setpoint is 93.3% of the nameplate rating of the 460-volt motors.

Submit the operating time curves for the above relays and demonstrate that, all Class lE equipments'including control fuses, thermal overloads, etc.)

design operating capability willbe'protected within the range defined by the relays operating curve for voltage and time.

The relay curve including

'the setpoint tolerances should be selected so as to provide protection of the most limiting group of Class 1E equipment, hardware, control circuits,'nd'nstruments.

2.

For surveillance requirements and allowing for relay drift, define the relay setpoints of voltage and time with minimum and maximum limits (+ tolerances).

4 3.

Submit draft proposed Technical Specifications changes to include the relay setpoints with tolerances, surveillance requirements, and limiting conditions of operation as required in Ref. 5.

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St. Lucie, Unit l.

'egraded Grid Protection O

Page 2 of 2 4.

Refs.

1 and 4 state that the undervoltage relays, are bipass'ed

.2 seconds after the diesel generator breaker closes-and automatically. reinstates upon opining of the diesel generator breaker.

-Does this bypassing/reinstatement' include the relays at both the 4 kV and 480-volt levels'osition '3, Item C

of Ref.

5 requires a test be included in the Technical Specifications to demonstrate that upon interruption of the diesel generators, the operability of the auto-reinstatement of. the bypassed relays, load'hedding and the subsequent reloading thiough the~sequencer occurs as'designed.

Submit a Technical Specification change to meet this iequi.rement 5.

. The additional relays 'to be added to the 480-volt load center buses stated

'n Ref.

4 indicate that only one relay will be installed at each bus.

If this

'is so, a spurious actuation or single failure of the relay will cause spurious load shedding, diesel generator starting and load sequencing.

This does not meet the NRC position of r'equiring coincident logic.

Provide a revised design to meet this requirement.

6.

Demonstrate that the 1 second time delay associated with the relay setpoint of 429 volts is adequate to preclude spurious trips during load-starting of the 460-volt motors -under worst case conditions submitted in Ref.'6, "Adequacy of Station Electric Distribution Systems Voltages".

Analysis results showed voltage transients to 82X voltage at the motor terminals.

8.

Pei telecons of Ref. 7, the licensee committed to submitting a verification

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that the overvoltage analysis presented in Refs.

3 and 6 does represent the

'worst case overvoltage condition during maximum grid voltage/minimum plant load conditions or a new analysis which does represent worst case overvoltages (such as during refueling)..

Submit either the analysis verification or the appropriate new analysis results.

Verify that all the design modifications will meet the requirements of IEEE 279-1971.

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