ML20008F327
| ML20008F327 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 03/06/1981 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8103120832 | |
| Download: ML20008F327 (4) | |
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UNITED STATES y
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March 6, 1981 O
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Docket No. 50-298
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U 9k MAR 11198W I2
WmYf Mr. J. M. Pilant Licensing and Quality Assurance 4
sio Nebraska Public Power District
'd P. O. Box 499 Columbus, Nebraska 68501
Dear Mr. Pilant:
Your letter of December 27, 1979 submitted a voltage drop analyses for Cooper Nuclear Station as requested in our letter of August 8,1979.
The staff has reviewed your submittal and determined that additional information is required before our review of the adequacy of your system can be completed. contains seven additional questions which you are requested to respond to within 45 days of reseipt of this letter.
Sincerely,
'u l. ' 1 A Thomas ppolito, Chief Operating Reactors Branch #2 Division of Licensing
Enclosure:
Request for Additional Information
- N 031201737
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Mr. J. M. Pflant Nebraska Public Power Distric 2-March 6,1981 cc:
Mr. G. D. Watson, General Counsel Nebraska Public Power District P. O. Box 499 Columbus, Nebraska 68601 Mr. Av nur C. Gehr, Attorney Snell & Wilmer 3100 Valley Center Pncenix, Arizona 85073 Coccer Nuclear Station ATT!i: Mr. L. Lessor Station Superintendent P. O. Box 98 Brownville, Nebraska 68321 Auburn Public Library 115 - 15th Street Auburn, Nebraska 68305
'tr. Dennis Dubois d5NRC Resicent Insce: tor F. O. Box 446 fie:raska City, NA 53a10
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ENCLOSURE 1
REQUEST FOR ADDITIONAL INFOR!!ATION COOPER ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYST;tt VOLTAG5S Reference 1; NRC letter (W. Ca= mill) to all Power Reactor Licensees, dated August 8, 1979.
Reference 2:
Nebraska Public Power District letter (J. Pilant) :n the NRC (D. Davis), da: td July 18, 1977.
Rei2rence 3:
Nebraska Public Power District letter (J. Pilant) to the NRC (W. Cannill), dated December 27, 1979.
Reference 4:
Nebraska Public Power District letter (J. Pilant) to the NRC (W. Camnill), dated August 11, 1980.
1.
Submit the following voltage ratings for the Class lE motor starter contactors.
a) Continuous operating voltage range b) Minimum pickup voltage c) Maximum dropout voltage 2.
Submit the calculated voltages for all low-voltage AC (?.ess than 480 volts)
Class lE buses or documentation which will verify that all low-voltage AC Class lE equipnent will be operating within their required voltage ratings for each case analyzed.
Do these buses supply any instruments or control circuits required by GDC-137 If so, is all equipment capable of sustaining the analyzed voltages without blowing fuses, overheating, etc., and without affecting the equipment's ability to perform the required safety function?
3.
' Ref. 4 details the voltage test perfor=ed on the electrical distribution
- 's t e c.
Input the c:acured bus voltages and bus landing values (fron the test) into the coeputer program, recalculate equipment voltages and compare actual measured equipment values to the calculated values.
This co=parison will produce a percent error difference in the voltages.
The purpose of the percent error is to verify the validity of the computer load flow program.
Submit the measured values, calculated values, percent error difference and identify the bus load percentage.
4.
Ref. 2, attachment 1, page 198 states that removing the isolated phase bus quick disconnect links will enable backfeeding through the main transformer and unit auxiliary transformer to the onsite distribution system.
If credit is not taken for backfeeding as a possible source connection from the grid in an existing limiting condition of operation, then an analysis is not required.
t 5.
Does Case 5, Ref. 3 represent the worst case maximum Class 1E load terminal voltages for maximum offsite grid voltage anc minimum plant load conditions (Guideline 11, Ref. 1)? If not, submit the worst case maximum Class lE load i
terminal voltages of all possible source connections.
6.
Per Guideline 3, Ref.1, provide an analysis of the effect on all Class lE equipment when starting and running the largest non-Class lE load aft,er load-ing the Class lE buses heavily during a LOCA for all possible source connec-tions.
The submitted analysis for the worst case voltage condition should in-clude Class 1E load terminal voltages before, during and af ter starting the large nonClass lE motor.
The analysis should also confirm that the second-Icvel of undervoltage voltage protection relays will not dropout during these loading conditions.
7.
Clarify the following items in the computer program printouts:
a) Does the steady state voltage drop results represent the worst case minimum steady state bus voltages teached for the conditions analyzed?
l b) In the voltage drop results due to motor starting, is each subcase motor started and loaded onto tLa bus and running before the next subcase motor is started and loaded onto the bus (loading sequencic3)?
The analysis should show that the last Class lE motor to be loaded onto the bus can start and operate within its, ratings while all other Class lE loads are running.
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