ML17249A276
| ML17249A276 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/09/1979 |
| From: | White L ROCHESTER GAS & ELECTRIC CORP. |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| TASK-05-06, TASK-08-01.A, TASK-RR NUDOCS 7911200539 | |
| Download: ML17249A276 (5) | |
Text
SUBJECT:
Submits info to support data points used in constructing thermal capability curveiFigure 2,3 1
o,f proposed Tech Spec change, Curve establishes max second level undervoltage relay allowable operating region.
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ACCESSION NBR:7911200539 C ~ DATE: 79/11/09 NOTARIZ; NO DOCKET FACIL:50-244 Robert Emmet Ginna Nuclear Plant~
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05000204 AUTH,NAME AUTHOR AfFILIATION WHITErL,D, Rochester Gas 8, Electric Corp.
REC IP, NAME RECIPIENT AFFILIATION ZIPMA'NN,D.L, Operating Reactors Branch 2
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89 EAST AVENUE, ROCHESTER, N.Y. I4649 LEON D. WHITE. JR.
VICE PRESIDENT TKLKPHONK AREA CODK 7IS 546-2700 November 9,
1979 Director of Nuclear Regulation Attention:
Mr. Dennis L. Ziemann, Chief Operating Reactors Branch 02 Division of Operating Reactors U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
Undervoltage Relay Modification R.E.
Ginna Nuclear Power Plant Referenced:
Proposed Technical Sp'ecification
- Change, July 25, 1979
Dear Mr. Ziemann:
In response to questions from your staff, the following information is offered which supports the data points used in constructing the thermal capability curve, Figure 2.3-1 of the referenced Technical Specification change.
This curve establishes the maximum second level undervoltage relay allowable operating region.
The Motor Divisions of the Westinghouse Electric Corporation were requested to perform calculations on all the safeguard motors to determine the time required, after a reduction in operating voltage, for the motor winding hot spot to reach the upper design temperature of 130'C, assuming a 40'C ambient.
Specifically, the upper temperature limit for insuring no degradation in the insula-tion design life is an 80'C rise over a 40'C ambient.
This assumes, for conservatism, that the winding hot spot temperature is taken to be 10 C above the average temperature.
Westinghouse has determined, by calculation, the time each motor takes to reach this temperature limit with motor terminal voltages at various levels below the lower 90% design limit.
Reduced voltage levels of 80%,
82.5% and 85% were chosen.
The worst case (i.e., the shortest time period) for an 80'C rise is shown below for the Auxiliary Feed Pump motor, the most limiting safeguard motor.
Motor Descri tion Calculated time at, indicated volta e, minutes Aux. Feed Pump 250
~80o 8.4 82.
5'1.4
~85'90'7.8 Never
I P'
galbe ROCHESTER GAS AND ELECTRIC C RP.
November 9,
1979 Mr. Dennis L. Ziemann, Chief SHEET NO.
The above data prints were used in the construction of Figure '2.3-1 of the proposed Technical Specification.
There is some degree of conservatism in the Westinghouse calculations.
Furthermore, the consequences of operating above this curve are by no means severe.
Should a motor experience a
hot spot temperature above 130'C, the motor insulation design life would be reduced.
This is a long term effect and since all motors at RG&E have a yearly inspection and a five year rewind or "dip and bake" schedule, no operational failure is likely, even if the 130'C tempreature were reached.
Very truly yours, L. D. White, Jr.
LDW:np