ML20115E847
| ML20115E847 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 04/11/1985 |
| From: | Tucker H DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8504190299 | |
| Download: ML20115E847 (4) | |
Text
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DUKE POWER GOMPANY P.O. HOX 33180 CHARLOTTE, N.C. 28242 HAL B. TUCKER gg,yp,ioys
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April 11,1985 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:
Ms. E. G. Adensam's letter of November 4, 1981 transmitted Question 430.9 which requested that tests and analysis of transformer tap settings be performed prior to initial full power reactor operation. This test was performed on the Catawba Unit 1 auxiliary power system during preoperational testing. The attached report describes the test and the analysis of the results. Since Catawba Units 1 and 2 are connected to the same switchyard and have identical auxiliary power systems, the transformer tap settings test will not be repeated on Unit 2.
Very truly yours, ed M Hal B. Tucker ROS:slb Attachment cc: Dr. J. Nelson Grace, Regional Administrator Palmetto Alliance U. S. Nuclear Regulatory Commission 21351 Devine Street Region II Columbia, South Carolina 29205 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Robert Guild, Esq.
NRC Resident Inspector P. O. Box 12097 Catawba Nuclear Station Charleston, South Carolina 29412 Mr. Jesse L. Riley Carolina Environmental Study Group 854 Henley Place Charlotte, North Carolina 28207 85 4190 ] ggj4N13 hO j
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Catawba Nuclear Station Verification of Voltage Analyses Response to Question 430.9 a.
As part of the preoperational test program at Catawba Nuclear Station, a transfomer tap setting test was performed on the Unit 1 auxiliary power system in accordance with the requirements of the Final Safety Analysis Report.
The purpose of the test was to verify that the Auxiliary System Design'0ptimization Program (AS00P) accurately models the auxiliary power system at Catawba and that AS00P can be used to analyza the perfomance of the auxiliary power system.
calculated voltages at various predetermined busses were obtaine compared to the voltage measured at these busses in the field.
The results were analyzed and the ASDOP calculated voltages showed good correlation with the field measured voltages, thus satisfying the requirements of Question 430.9 The test was performed in two parts.
WaterPump(RN) Motor). power system during the starting o The second test monitored steady-state conditions Some variations were made to the test method outline and are detailed below:
1)
Part 4 of Question 430.9 specifies that the test should be performed for "all sources of offsite power". At Catawba, Unit I and are connected to the same switchyard (offsite power source). Unit 2 the impedance of the auxiliary ' system through either the normalAlso, analysis was p(SATA, SATB) is approx)imately t transformers Therefore, the system lineups.erformed on Train A and is applicable to all auxiliary 2)
Part 4A of Question 430.9 specifies that all Class IE station distribution levels down to the k
208/120V level be loaded to at least 30%.
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A Paga Two Because of difficulties in obtaining any appreciable loading below the 600V level, only busses down to and including the 600V motor control centers were monitored.
in some busses being loaded to less than 30%. Loading difficulties also result the loading in the distribution system for the two tests:The table below gives Approximate Load During Percent of Transformer Full Load Amps Test Full Load Test #1:
1A 16,574 1,507 9.1%
IT2A 1,172 780 66.5%
1ATC 833 207 24.8%
1ETXA 1,154 470 40.7%
Test #2:
1A 16,574 2,175 13.1%
IT2A 1,172 807 68.8%
1ATC 833 327 39.3%
1ETXA 1,154 390 33.8%
.The load on Main Step-Up Transformer 1A was low; however, this transformer is sized to carry half of the generator output. With the dual generator circuit breaker design used at Catawba, the step-up transformer will be operating at a low load any time it is supplying plant auxiliary power.
The field measurements taken during the tests give good correlation with the results calculated by ASD0P. This favorable comparison satisfies the requirements of Question 430.9 by verifying that ASD0P accurately models the Catawba auxiliary power system and that ASD0P can be used to analyze the performance of the auxiliary power system.
The results of the tests and the voltage comparison are shown below:
Steady-State Test Field Measured ASD0P
^~
Bus' Vol tage Voltage
%zi ITA 6.867 KV = 0.9952 pu 0.9812 pu
-1.41%
1 ETA 4.187 KV = 1.0065 pu 0.9938 pu
-1.26%
IELXA 606.33 V = 1.0106 pu 1.0057 pu
-0.485%
IEMXG 604.25 V = 1.0071 pu 1.0000 pu
-0.705%
Page Three NC Pump Motor Start Test Field Measured ASD0P Bus Vol tage Vol tage
%o ITA 6.219 KV = 0.9013 pu 0.8795 pu
-2.42%
1 ETA 3.652 KV = 0.8779 pu 0.8874 pu 1.08%
1ELXA 553 V = 0.9217 pu 0.8941 pu
-2.99%
1EMXG 550.84 V = 0.9181 pu 0.8874 pu
-3.34%
RN Pump Motor Start Test Field Measured ASD0P Bus Voltage Voltage
%A ITA 6.906 KV = 1.0009 pu 0.9711 pu
-2.98%
1 ETA 3.965 KV = 0.9531 pu 0.9443 pu
-0.923%
1ELXA 571 V = 0.9517 pu 0.9526 pu 0.095%
1EMXG 568.1 V = 0.9468 pu 0.9445 pu
-0.243%
Table of Results As shown above, the voltage comparison for the IEMXG voltage during the NC Pump Motor Start shows a 3.34% difference between the measured and calculated vol tages.
Since the ASDOP calculated voltage is more conservative than the field data, this difference is acceptable.
For all but two of the cases shown in the table above, the ASD0P calculated voltages were lower (more conservative) than the field measured voltages.
The comparison of the IETA bus voltages for the NC pump motor start shows the calculated voltage to be 1.08%(44.93 volts on a 4160 V base) higher than the measured voltage, and for the RN pump motor start test the IELXA calculated voltage is 0.095%(0.57 volts on a 600 V base) higher than the field measured voltage. For these two cases an additional comparison must be made to satisfy the requirements of Question 430.9, which states: "In general the test results should not be more than 3% lower than the analytical results; however, the difference between the two when subtracted from the voltage levels determined in the original analyses should never be less than Class 1E equipment ratings". Therefore, the voltage difference on these two busses must be subtracted from the worst case bus voltage calculated t>y ASDOP in the original Auxiliary System Voltage Study.
This additional analysis was performed for these two cases, and the IETA and IELXA voltages were well above their corresponding Class IE equipment ratings.
The favorable results obtained in the comparison of actual versus calculated voltages satisfy the requirements of Question 430.9 of the Final Safety Analysis Report.