ML20049A641
| ML20049A641 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 09/16/1981 |
| From: | Maskell S Office of Nuclear Reactor Regulation |
| To: | Siegel B Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20049A645 | List: |
| References | |
| TAC-13148, NUDOCS 8110010073 | |
| Download: ML20049A641 (2) | |
Text
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UNITED STATES t,
NUCLEAR REGULATORY COMMISSION g
WAsHmGTON, 0. C. 20555
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SEP 161981 MEMORANDUM FOR: t%E6n ~Siegel. Operating R2 actors Branch No. 2, DL FROM:
Steve Maskell, Power Systems Branch, DSI
SUBJECT:
TELEPHCNE CONFERENCE CALL ON ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES FOR THE COOPER NUCLEAR STATION This memo confinns the September 9,1981 telephone conversation between B. Siegel NRC), S. Maskell (NRC), J. Grabel (B&R), P. Shenoy (B&R), and J. Weaver NPPD) concerning verification of the ability of instrument and control equipment to operate satisfactorily during voltage degradation of 84.8% on the 120 VAC bus.
Mr. Shenoy explained that all equipment powered from the 120 VAC 1E busses which were necessary for safa shutdown, were connected either via the reactor protection system motor-generator set or via the uninterruptable power supply. These voltage regulating devices will maintain a <.11 %' Vol tag e bandwidth over a 120% voltage input.
Those loads powered from the 120 VAC 1E busses which are not necessary for
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safe shutdown, are energized at 24 VDC via power supplies which maintain a flat output for 110% voltage input changes.
For voltages beyond 110%,
the regulator output voltage changes 0.004% for each one volt change of input.
Burns & Rowe estimate that at 84.8% of normal voltage on the 1E bus, the 24 VDC output will degrade by 0.025%.
Please send a copy of this memorandum to the licensee.
hrA M'
Steve Maskell Power Systems Branch Division of systems Integration ec:
J. Selan, EG&G A. Ungaro M. Srinivasan S. Mukell
Attachment:
Original Requert for Additional Information.
8110010073 810923 pA Apocx oso g e
n O
o' REQUEST FOR ADDITIONAL INFORMATION COOPER
,o ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES REF.1: NPPD letter (Jay M. Pilant) to NRC (T. A. Ipp'olito),
dated May 4, 1981 (1) The bus voltage percentages presented for cases 6 and 7 in Table 1. Ref.1, show that the bus voltage (lowest steady state value of 84.8%) is below the continuous operating voltage rating of -10% of 120 volts for the Class 1E instruments and controls.
In response, a statement is made that "...all equipment connected to these buses are capable of susta~1ning the analyzed voltages without blowing fuses, overheating, etc., and without affecting the equipment's ability to perfom the required safety function."
Submit the basis under which the instrument and control equipment were found satisfactory for operation below their continuous operating ratings.
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