05000267/LER-1982-044, Forwards LER 82-044/03L-0.Detailed Event Analysis Encl

Forwards LER 82-044/03L-0.Detailed Event Analysis Encl

ML20071Q300
Person / Time
Site:	Fort Saint Vrain
Issue date:	12/08/1982
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20071Q303	List: 05000267/LER-1982-044, Forwards LER 82-044/03L-0.Detailed Event Analysis Encl
References
P-82545, NUDOCS 8212290297
Download: ML20071Q300 (5)

LER-2082-044, Forwards LER 82-044/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2672082044R00 - NRC Website

text

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public service company e Odonde

• 16805 Road 19 1/2, Platteville, Colorado 80651-9298 December 8, 1982 Fort St. Vrain Unit No. 1 P-82545 Mr. John T. Collins, Regional Administrator Region IV Nuclear Regulatory Commission 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011 .

Reference:

Facility Operating License No. DPR-34 Docket No  ;

Dear Mr. Collins:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/82-044, Final, submitted per the requirements of Technical Specification AC 7.5.2(b)2.

Also, please find enclosad one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/82-044.

Very truly yours, Ocn wes..,, dy ov]dlvknA Don Warembourg Manager, Nuclear Production DW/cls  !

Enclosure cc: Director, MIPC di VW l

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t 's 8212290297 821208 DR ADOCK 05000267 PDR

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REPORT DATE: December 9, 1982 REPORTABLE OCCURRENCE 82-044 ISSUE O OCCURRENCE DATE: November 10, 1982 Page 1 of 4 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 19 1/2 i PLATTEVILLE, COLORADO 80651-9298 l

REPORT NO. 50-267/82-044/03-L-0 l

Final IDENTIFICATION OF OCCURRENCE:

During the period beginning November 10, 1982, and ending November 11, 1982, with the reactor operating and the average core outlet temperature less than 725 degrees fahrenheit, the primary coolant dewpoint temperature exceeded 67 degrees fahrenheit for 22.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. This event constitutes a degraded mode of LCO 4.2.11 and is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2.

EVENT DESCRIPTION:

On November 10, 1982, at approximately 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br />, the calculated primary coolant dewpoint temperature exceeded the limits set forth by Figure 4.2.11-1 of the Fort St. Vrain Technical Specifications due to unusually high moisture levels in the reactor vessel. The reactor

.was being maintained less than 5% power with the average core outlet temperature less than 450 degrees fahrenheit.

At 0715 hours0.00828 days <br />0.199 hours <br />0.00118 weeks <br />2.720575e-4 months <br /> on November 11, 1982, the control rods were inserted to the point of just maintaining criticality. The corresponding reduction in primary coolant teinperature and pressure caused the calculated primary coolant dewpoint temperature to return within the limits of Figure 4.2.11-1 at approximately 0745 hours0.00862 days <br />0.207 hours <br />0.00123 weeks <br />2.834725e-4 months <br /> on November 11, 1982.

The highest dewpoint attained was 81 degrees fahrenheit at 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> on November 10, 1982 (see Table 1).

CAUSE DESCRIPTION:

The primary ccolant temperature at the onset of the event was suf11cient to increase the vaporization rate of water that was present in the reactor vessel to the point where moisture was being entrained in the primary coolant faster than the helium purification system could remove it. '~

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REPORTABLE OCCURRENCE 82-044 ISSUE O Page 2 of 4 CORRECTIVE ACTION:

Upon indications that the calculated primary coolant dewpoint temperature was not returning within the limits of Figure 4.2.11-1, ,

the control rods were inserted to a point of just remaining critical.

The corresponding decrease in primary pressure and temperature brought the dewpoint within limits.

No further corrective action is anticipated nor required.

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. REPORTABLE OCCURRENCE 82-044 ISSUE O Page 3 of 4  ;

TABLE 1 l l IAverage CorelCalculated Primary l l l l 10utlet Temp-l Coolant Dewpoint Figure 4.2.11-11 l Date ITimelerature ( F)l Temperature (*F) Region l I I I I i i 111-10-8210800l 416 I 64 iAcceptable l l l 1 I I I l--------l----l-----Event Starts at 0900------l---------------l l l l l l 1 l l1000] 416 1 70 [Not Acceptable i I I l l 1 l l 11200l 417 I 71 lNot Acceptable i I l l l l l l l14001 419 I 77 lNot Acceptable l l l l l l l l l16001 419 I 69 lNot Acceptable l l l l l l l l l18001 411 1 70 lNot Acceptable l l l l l 1 1 I l2000l 412 l 76 lNot Acceptable l l l l l l l l 122001 400 1 81 lNot Acceptable l l 1 I I I I 111-11-82l0000l 399 I 78 INot Acceptable l l I I I I I I 102001 398 I 74 INot Acceptable I i i l I I I l 104001 399 [ 72 lNot Acceptable l I I I I I I l 106001 401 l 71 lNot Acceptable I I l l l l l l 10715] 400 l 74 (Note 1) INot Acceptable i I I I I I I l--------l----l------Event Ends at 0745-------l---------- ----l l l 1 1 I I l l08001 295 l 64  ! Acceptable l NOTE 1: The 0715 hour0.00828 days <br />0.199 hours <br />0.00118 weeks <br />2.720575e-4 months <br /> reading of 74 degrees fahrenheit was taken from the Shift Supervisor's Station Log. All other dewpoints were calculated directly from primary coolant parameters. ,

REPORTABLE OCCURRENCE 82-044 ISSUE O Page 4 of 4 l

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Prepared By:

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d j Owen J. ayton /f Senior hnical Mrvices Technician 1

Reviewed By: ~ 4/I4 ///~

Charles Fuller Technical Services Engineering Supervisor Reviewed By: Y 42 [

Edwin O. Hill Station Manager Approved By: Do, Wa<< ,6 m , e 7N(z m,o,;A Don Warembourg Manager, Nuclear Production

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