ML19256F333

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Monthly Operations Rept 68 for Aug 1979
ML19256F333
Person / Time
Site: Fort Saint Vrain Xcel Energy icon.png
Issue date: 09/18/1979
From:
PUBLIC SERVICE CO. OF COLORADO
To:
Shared Package
ML19256F332 List:
References
NUDOCS 7912180513
Download: ML19256F333 (5)
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PUBLIC SERVICE COMPANY OF COLORADO EDKT ST. VRAIN NUCLEAR GENERATING STATION f

MONTriLY OPERATIONS REPORT NO. 68 AUGUST, 1979 l

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This report contains the highlights of the Fort St. Vrain, Unit No.1 activi-ties, operated under the provisions of the Nuclear Regulatory Com=ission Oper-ating License, DPR-34. This report is for the month of August, 1979.

1.0 NARRATIVE

SUMMARY

OF OPERATING EXPERIENCE AND MAJOR SAFETY RFLATED MAINTENANCE 1.1 S u= mary Turbine generator was placed on line at 1504 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.72272e-4 months <br /> August 3,1979.

Turbine remained on line until 1937 hours0.0224 days <br />0.538 hours <br />0.0032 weeks <br />7.370285e-4 months <br /> August 11, 1979; at this time a reactor scram, turbine trip, and Loop 2 shutdown was precip-itated by a loss of speed signal to "D" helium circulator.

Turbine generator was placed on line at 1830 hours0.0212 days <br />0.508 hours <br />0.00303 weeks <br />6.96315e-4 months <br /> August 12, 1979.

The plant was operated at reduced power levels (150 K4e) due to con-tinuing problems with helium circulator speed circuit ry.

On August 17, 1979, a Loop I shutdown, two loop trouble scram, tur-bine trip, and an approximate three minute Icss of forced cooling occurred at 1523 hours0.0176 days <br />0.423 hours <br />0.00252 weeks <br />5.795015e-4 months <br />. The plant shutdown was caused by an inad-vertant grounding of the 120 volt AC power feed to cabinet I-36B.

Turbine generator was placed on line at 1150 hours0.0133 days <br />0.319 hours <br />0.0019 weeks <br />4.37575e-4 months <br /> on August 20, g 1979, and remained on line until 1518 houru August 24, 1979. Power was reduced and the turbine was taxen off line due to high primary coolant oxidant levels.

Turbine was placed on lint at 1253 hours0.0145 days <br />0.348 hours <br />0.00207 weeks <br />4.767665e-4 months <br /> August 26,19 79, and re-mained on line until the plant was shutdown on September 1,1979, to evaluate seismic qualification of Class I 2-1/2 inch and latsar piping and hangers.

Testing consisted of core region thermocouple traverses - RT 524, base data an FM fluctuation data system at 46% power - RT 486, re-heat steam attemperation tuning - RT 501, and fluctuation testing -

RT 500F. PCRV deflection measurement was completed at 625 psia PCRV pressure on August 9,1979. . Fuel element surveillance pro-gram has been completed, equipment decontaminated, and shipped to General Atomic Company in San Diego.

Maintenance was performed on the following valves: V-2126 8-2, back-up bearing water header relief valve, V-2256, condensate check valve, and HV-2224, main steam stop check valve.

The overhaul of "C" boiler feed pump was completed. The boiler feed pump was test run and returned to service.

1.2 Discussion I

e [ Turbine generator was synchronized with the grid at 1504 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.72272e-4 months <br /> Au-s_

us t 3, 19 79. Power operation continued until 1937 hours0.0224 days <br />0.538 hours <br />0.0032 weeks <br />7.370285e-4 months <br /> August 11, i 19 79. At this time, a reactor scram, turbine trip, and Loop 2 I

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1.0 NARRATIVE

SUMMARY

OF OPERATING EXPERIENCE AND MAJOR SAFETY RELATED MAINTENANCE (continu2d)_

l.2 Discussion (continued) shutdown was initiated by a loss of "D" circulator speed feedback control signal. The loss of speed signal causes the circulator to overspeed and trip when the circulator speed exceeds the limits of the Plant Protective System circulator speed /feedwater flow pro-gram. The loss of speed signal is believed to be due to a resis-tance change at the field connector which mates with the circulator bulkhead connector. The resistance change causes an imbalance at the speed modifier and a loss of output signal. Reactor scram oc-curred when the hot reheat steam temperatures exceeded 1,059'F.

Loop 2 feedwater was isolated due to low feedwater flow. Low feed-water flow occurred as the operator was removing "C" boiler feed pump f rom service. The turbine automatically tripped 120 seconds af ter the reactor scram.

Field connectors which mate with the circulator bulkhead connectors have been ordered from ITT Cannon. The delivery schedule has been expedited and a test connector was received on August 31, 1979.

The test connector will be shipped to Wyle Laboratories for environ-mental testing. The remaining connectors are to be shipped prior to Septecher 24, 1979.

f-Turbine generator was placed on line at 1830 hours0.0212 days <br />0.508 hours <br />0.00303 weeks <br />6.96315e-4 months <br /> August 12, 1979.

Loss of helium circelator speed signals continued to cause plant upsets. "D" helium circulator tripped at 0040 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> August 16, 1979, due to loss of circulator speed feedback control signal. Reacto r power and turbine runback to approximately 50% of rated load, due to the tripping of "D" helium circulator.

On August 17,1979, at 1523 hours0.0176 days <br />0.423 hours <br />0.00252 weeks <br />5.795015e-4 months <br />, a Loop 1 shutdown, two loop trouble scram and turbine trip were the consequences of an inadver-tent grounding of the 120 volt AC power feed to cabinet I-36B. This upset also resulted in a temporary loss of forced cooling for ap-proximately three minutes. The grounding of the power feed occurred as plant personnel were installing a high selector on the output of "D" circulator steam and water tur'. ,

pulse to current trans-mitters. This circuit modification prc ; des a speed signal to the control system from either of the identical speed elements. There-fore, a loss of a single speed modifier will not result in a circu-lator trip. A reportable occurrence report was submitted to the Nuclear Regulatory Commission on August 31, 1979. This is a pre-liminary report which provides the details of the August 17, 1979, plant upset.

Turbine generator was placed on line at 1150 hours0.0133 days <br />0.319 hours <br />0.0019 weeks <br />4.37575e-4 months <br /> August 20, 1979.

Due to high primary coolant oxidants (greater than 10 ppm total oxidants) power was reduced and the turbine was taken off line at

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1518 hours0.0176 days <br />0.422 hours <br />0.00251 weeks <br />5.77599e-4 months <br /> August 24, 1979. The high primary coolant oxidant level I

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.' l.0 NARRATIVE

SUMMARY

OF OPERATING EXPERIENCE AND MAJOR SAFETY RELATED MAINTENANCE (continued) 1.2 Discussion (continued) was caused by low buffer helium dryer tower regeneration tempera-tures. Improper regeneration of the desiccant beds allowed moisture laden helium to enter the primary coolant via the helium circulator buffer helium system.

Turbine was placed on line at 1253 hours0.0145 days <br />0.348 hours <br />0.00207 weeks <br />4.767665e-4 months <br /> August 26, 1979. Power operation continued until the plant was shutdown on September 1, 1979, to evaluate seismic qualification of the Class I, 2-1/2 inch and larger piping and hangers.

1.3 Testing The following tests were completed:

RT-524, Part 1 - mini traverse for all 26 core region outlet thermocouples RT-524, Part 2 - traverse core region outlet thermocouples in penetrations E2 and E5 e

RT-486, Part 1 - base data on FM fluctuation data system at 46% power RT-501 - reheat steam attemperation system tuning RT-500F - fluctuation testing at 40% and 50% power levels A totcl of 63 Technical Specification tests were completed; 30 were surveillance tests, 30 were preventive maintenance tests, and three were non-radiological tests.

1.4 Equipment During the installation of a backup bearing water header relief valve (V-21268-2) , two mechanics received minor burns. The accident occurred when hot water was released during the removal of the blind flange from the relief valve tail pipe. V-21268-2 had previously been removed for repair.

Condensate check valve V-2256 developed a leak at the pivot pin pres-sure seal. The leak was repaired on line by furmaniting.

HV-2224 main steam stop check valve developed an oil leak at the j lower cylinder head seal. The leak was repaired on line by using a special jacking device to assist in the reassembly.

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2.0 SINGLE RELEASES OF RADIOACTIVITY OR RADIATION EXPOSURE IN EXCESS OF 10% OF THE ALLOWABLE ANNUAL VALUE None 3.0 INDICATION OF FAILED FUEL RESULTING FROM IRRADIATED FUEL EXAMINATIONS None 4.0 MONTHLY OFERATING DATA REPORT Attached

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I DOCKIT NO. 50-267 o?tRAUNG DATA REPORT DATE 790901 COMP.rTED BY J. W. Gahm Trt. Pa0Nr (303) 785-2253 OPERATING STATUS NOTLS

1. Unit Name: Fort St. Vrain. Unit No. 1
2. Reporting Period: 790801 thru 790831
3. Licensed Thermal Power OEt): 842
4. Nameplate Rating (Gross We): 342
5. Design Electrical Rating Oiet We): 330
6. Maximum Dependatie Capacity (Gross We): 342
7. Maximu= Dependable Capacity (Net We): 330
8. If Changes occur in Capacity Ratings (Items Nunber 3 Through 7) Since Last Report. Give Reasons:

None

9. Power Level To Which Restricted If Any (Net We): 231
10. Reasons fcr Restrictions, If Any: Nuclear Regulatorv Cor=1ssion restriction (70~:) pending resolution of te=perature fluctuations.

This Msnth Year to Date Cu::ralative

11. Hours in Reporting Period 744 5,831 1,488 712.7 2,556.0 16,029.7
12. Ncaber of Ecurs Rzactor Was Critical
13. Reactor Reserve Shutdown Bours 0.0 0. 0 0.0 542.5 1,293.4 9,136.0
14. nours cenerator on-Line
15. Unit Reserve Shutdown Bours 0.0 0.0 0.0
16. cross Thermal Inergy cenerated (Wa) 253,407 628,291 3,831,289 Cross Electrical Energy Generated (5'd) 88,079 202,453 1,150,723 17.

Net Electrical Energy cenerated (Ws> 81,868 183,045 1,034,496 18.

72.9% 42.2% 42.2%

19. Unit Service Factor
20. Unit Availability Factor 72.9% 42.2% 42.2%

Unit Capacity racter (using MDC Net) 33.3% 16.7% 16.7%

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22. Unit Capacity Factor (Using DER Net) 33.3% 16.7% 16.7%
23. Unic Forced Outage Race 27.1% 57.7% 57.7%
24. Shutdowns Scheduled over Next 6 Months (Type. Date October 20. 1979 30 Days
25. If Shut Down at End of Report Period. Estimated Da DUPLICATE DOCUMENT
26. Units In Test Status (Prior to Cor::nercial Operatio .

Entire document previously InnAL CnTICALIn entered into system under:

INITIAL ELICTRICIU ANO COMMERCIA:. OPERA!!ON ( '

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