ML20079J298
| ML20079J298 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 01/17/1984 |
| From: | Tucker H DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8401240283 | |
| Download: ML20079J298 (2) | |
Text
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s Duxn POWER GOMPANY P.O. IBOX 33180 CHARLOTTE, N.C. 28242 TELEPHONE IIAL H. TUCKER (ro4)a n4 san
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January 17, 1984 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention:
Ms. E. G. Adensam, Chief Licensing Branch No. 4 Re: Catawba Nuclear Station Docket Nos. 50-413 and 50-414
Dear Mr. Denton:
Section 8.4.10 of the Catawba Safety Evaluation Report. discusses Confirmatory Item 38, 100% Load Reduction Capability.
In response to this item, please find attached a revised response to Question 430.110.
Very truly yours, WMWM Hal B. Tucker ROS/php Attachment cc:
Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303 NRC Resident Inspector Catawba Nuclear Station Mr. Robert Guild, Esq.
Attorney-at-Law P. O. Box 29412 Palmetto Alliance 213515 Devine Street Columbia, South Carolina 29205 Mr. Jesse L. Riley ik)
Carolina Environmental Study Group
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1 854 Henley Place Charlotte, North Carolina 28207 l
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8401240283 840117 PDR ADOCK 05000413 E
CN3 430.110 Section 10.4.4.1 of the FSAR indicates Catawba can accept up to 100%
turbogenerator load reduction without tripping the reactor or main steam relief valve actuation.
Since this allows the turbine gene-rator to t-emain on line powering station loads following a loss of the offsite power system, describe the magnitude and effect of the transient and steady state voltage and frequency output of the main generator on the station loads (especially on Class 1E loads) starting with and following load reduction.
Response
If the turbine generator is subjected to a 100% load reduction, the maximum voltage on the output of the generator is estimated to be approximately 129% of rated with the period of the excursion where voltage is above 110% of rated being approximately 3.2 seconds.
The maximum frequency is estimated to be approximately 107.5% of rated.
The minimum values of voltage and frequency do not exceed normal equipment ratings.
Per industry standards, power equipment such as 4 KV switchgear, 4160/600 V transformers, and 600 V switchgear is designed to withstand voltages in excess of 1.4 per unit for a duration of 60 seconds.
Motors are typically subjected to hi pot tests at 2150 volts for volt motors, and 9000 volts for 4 KV motors for a duration of 60 seconds.
Although industry standards which define voltage ratings / limits are not available on every type of equipment, industry experience has not indi-cated a problem with voltage excursions follvwing load rejec-tions.
the frequency excursion would result in a motor speed increase of 7 %; however, NEMA standards require that motors be designed to withstand overspeeds of 20% for short durations without damage.
Although the turbine generator is designed to accept a 100% load rejection, it is extremely unlikely that the unit will be sub-jected to a 100% load reduction while remaining on line powering station loads.
This is especially the case since the unit is tied to the switchyard through two separate circuits which terminate in separate bays of a breaker-and-a-half arrangement.
430-53 Rev. 9
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