ML19242A286
| ML19242A286 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 06/15/1979 |
| From: | Lainas G Office of Nuclear Reactor Regulation |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7908010303 | |
| Download: ML19242A286 (4) | |
Text
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ggR RECg UNITED STATES
[%'g NUCLEAR REGULATORY COMMISSION S
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.C WASHINGTON, D. C. 20555 o '?ii y
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JUN 151979 MEMORANDUM FOR:
R. Reid, Chief, Operating Reactors B, anch d4, Division of Operating Reactors FROM:
G. Lainas, Chief, Plant Systems Branch, Division of Operating Reactors
SUBJECT:
ARKANSAS NUCLEAR ONE UNIT 1 ( ANO-1) ELECTRIC POWER DISTRIBUTION SYSTEM ITAC 08457)
We have prepaced the enclosed set of q_estions to be transnitted to the licensee.
Also, during a telecon between G. Vissing et al. (NRC) and T. Ennis et al.(AP&L) on April 26, 1979, the licensee agreed to provide certain additional information.
This information has not been received.
Therefore, questions #7 through #11 are included to cover those items previously agreed to.
We believe that satisfactory answers to these questions will allow us to complete our technical review of the proposed mocification for pro-tection of the ESF equipment from degraded electric power conditions.
We request that these questions be provided to the licensee as soon as possible.
The licensee stated in his August 23, 1978 ietter that he would propose the technical specifications associated with this modification at a later date.
We recommend that these specifications be submitted with the responses to our questions.
/. N G. Lainas, Chief Plant Systems Branch Divisior of Operating Reactors
Contact:
J. T. Beard, X28077 cc w/ enclosure:
See next page f
m;b s,s 7008010369 cc w/ enclosure:
D. Eisenhut R. Vollmer B. Grimes G. Lainas F. Rosa G. Vissing D. Tondi J. T. Beard M. Lhiram 1
- 1. Ahmed S. Rhow
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REQUEST FOR ADDITIONAL INFORMATION ARKANSAS NULCEAR ONE UNIT 1 ( ANO-1)
ELECTRIC POWER DISTRIBUTION SYSTEM (tar 08457) 1.
The proposed second lev.1 protection includes two-out-of-two coincidence to cause protective action.
Describe the feature (s) of the design which wiil permit automatic protective action when one of the two channels is out of service (for calibration, repair, etc.)
2.
Describe the design pr ovision to automatically reinstate the degraded voltage protection system (both levels of protection) when the supply breaker from onsite source is opened and, conversely, blocking the under-voltage protection when the onsite source is supplying power to ESF busses.
3.
Describe the features of the under-voltage protection system that facilitate periodic testing.
4.
- a. Describe. the testing to be performed on the undei-voltage protection system.
- b. Describe how the testing program will demonstrate that, when the grid is at the defined "minimun-normal" condition, no unacceptable voltage is applied to ESF equipment.
(If actual test cannot fully simulate such a id condition, sufficient tests should be conducted to facilitate extrapolation of the measured data with a high confidence level).
- c. Describe how tne testing program will demonstrate that, under the defined " minimum-normal" supply condition, no unacceptable electric power will be applied to ESF equipment during the starting of large non-Class lE motors.
5.
The proposed under voltage protection includes transformers tap changes.
Provide the analysis that shows that, under high-normal conditions of grid voltage and no-load conditions, the voltages applied to ESF equipment will not exceed acceptable values.
6.
The proposed under-voltage protection modification includes a bypass of the second level protection during the starting of large, non-Class lE motors.
Provide the schematic diagrams involved in this aspect of the proposed modification Discuss how this bypass satisfies IEEE-279, with particular cons.deration to the fact that the bypass originates in non-lE equipment and operates in both civisions of the Class lE electric power system.
7.
For each secticn of IEEE 279, describe how the proposed under-voltage protection modification complies with the criteria.
8.
The proposed under-voltage protection includes shedding of non-essential loads.
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. a. What is the maximum load (MVA) that may be transferred to ST-1/ST-2 (worse case)?
- b. Identify specifically which loads must be shed.
- c. Provide appropri % electrical diagrams which portray this 3
shedding.
9.
The ANO-1 analysis assumed that protective action would be executed at (or above) the calculated value of 92% (motor-base) voltage.
Indicate:
(a) nominal value of this setpoint, (b) the allowance (above 92%) used to accommodate all inaccuracies, and (c) allowance (above 92%) used to accommodate drifts.
Jescribe the basis for determining these allowances.
Describe t le bases for determining the nominal setpoint which provides maximum I rotection censistent with minimum spuriou; shedding from tha pt eferred powtr source (i.e., electric grid).
10.
The AP&L submittal dated August 23, 1978 indicated that the setpoint for the under-frequency trip would be 59.9Hz.
We understand this value is erroneous.
Please indicate the correct value for this setpoint.
11.
We understand that AP&L proposes to use interposing relays to improve control circuitry voltage situction.
Provide typical diagran.s showing these circuit changes and state the criteria and design voltage limits that will be imposed, b}C bb