ML19344E102

Forwards LER 80-036/03L-0

ML19344E102
Person / Time
Site:	Fort Saint Vrain
Issue date:	08/05/1980
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19344E103	List: ML19344E102 ML19344E105
References
P-80246, NUDOCS 8008260631
Download: ML19344E102 (5)

Text

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I,5 Public service company e conende 16805 ROAD 19%

'/' l PLATTEVILLE, COLOR ADO 80651 August 5, 1980 Fort St. Vrain Unit No. 1 P-80246 Mr. Karl V. Seyfrit, Director gNpciear Regulatory Comission Region IV Office of Inspection and Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012

Reference:

Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/

80-36, Final, submitted per the requirements of Technical Specification AC 7.5.2(b)2.

Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/80-36.

Very truly yours, L 4)d Don Warembourg

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( Manager, Nuclear Production l

DW/cis

! Enclosure cc: Director, MIPC fo03 b lll 8008260 h/ - . . -

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OCCURRENCI REPORT DISTRIBLTION Number of Copies Department of Energy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter)

San Francisco Operatione Of fice Aten: California Patent Group 1333 Broadway Oakland, California 94612 Depa r tmen t o f Ene rgy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter)

Office of Nuclear Engineering Progrzas Washington, D.C. 20545 Dep artmen t o f Ene rgy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter)

tr. Glen A. Newby, Chief HTR 3 ranch Division of Nuclear Power Development Mail Station 5-107 Washington, D.C. 20545 Dep artmen t o f Ener gy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter)

Atts: Senior Program Coordinator P. O. Box 31325 San Diego, California 92133 Mr. Karl V. Seyfrit, Director ------------------------- (Original of P Letter Region IV and Copy of LER)

Of fice of Inspection a; . dnforcement Nuclear Regulatory Commission 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 .

Di r e c to r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter, LER)

Of fice of Management Information and Program Control U. S. Nuclear Regulatory Commission Washington, D.C. 20555 W. Bushnell, Site Manager - -------------------------- 10 (Original of FPLF. Letter General Atomic Company plcs Two Copics, One P. O. Box 426 Copy of P Lettir, One Platteville, Colorado 80651 Copy of LER)

NRC Rasident Site Inspector -------------------------- 1 (P Letter. LIR)

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REPORT DATE: August 5. 1980 REPORTABLE OCCURRENCE 80-36 ISSUE O OCCURRENCE DATE: July 6, 1980 Page 1 of 3 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 19 1/2 PLATIEVILLE, COLORADO 80651 REPORT NO. 50-267/80-36/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

Between July 6,1980, and July 8,1980, with the reactor operating at power, the total primary coolant oxidants exceeded the limits of LCO 4.2.10, and the reactor dewpoint exceeded the limits of LCO 4.2.11.

This constitutes operation in a degraded mode of LCO 4.2.10 and LCO 4.2.11, and is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2.

EVEY.r DESCRIPTION:

Following the June 17 loop shutdown and turbine trip, preparations were made for the return to power, and the turbine generator was placed on line at 0626 hours0.00725 days <br />0.174 hours <br />0.00104 weeks <br />2.38193e-4 months <br />, June 30, 1980. Reactor power was increased to about 45: until excess moisture required a reduction af power to be in compliance with LCO 4.2.11 (See R0 50-267/80-33/03-L-0).

( Following this power reduction, power was increased while keeping the average l core outlet temperature low enough to avoid exceeding the allowable reactor dewpoint of LCO 4.2.11.

This continued until July 6, 1980, at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> where primary coolant moisture again began increasing and the reactor dewpoint went into the limited acceptable area of Figure 4.2.11-1. Reactor power was reduced to prevent exceeding the allowable reactor dewpoint. By 2400 hcurs on June 6, 1980, the reactor dewpoint was again in the acceptable area of Figure 4.2.11-1.

On June 7,1980, reactor power was again increased while maintaining reactor dewpoint within the limits of Figure 4.2.11-1. This continued till approxi-mately 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br /> when the System Control Center asked for more power to com-pensate for the losses of a unit and some purchased power. Reactor power was increased to 55% and the average core outlet temperature exceeded 1200*F.

With total primary oxidants greater ch'an 10 ppm, this resulted in operation in a degraded mode of LCO 4.2.10. This continued until approximately 1830 hours0.0212 days <br />0.508 hours <br />0.00303 weeks <br />6.96315e-4 months <br /> when the System Control Center notified the plant that the day's pcak l demand was over and power reduction could begin. At approximately 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />,

! average core outlet temperature dropped below 1200*F, ending the period of operation in a degraded mode of LCO 4.2.10.

REPORTABLE OCCURRENCE 80-36 ISSUE O Page 2 of 3 EVENT DESCRIPTION: (Cot.t ' d)

The reactor dewpoint at this time was higher than allowed by Figure 4.2.11-1 and a degraded mode of LCO 4.2.11 was entered. This continued as reactor power was decreased until 0837 hours0.00969 days <br />0.233 hours <br />0.00138 weeks <br />3.184785e-4 months <br /> on July 8,1980, when a reactor scram occurred.

CAUSE DESCRIPTION:

The increase in prie:ry coolant moisture and reactor dewpoint during this period is being attributed to residual moisture from the June 17 circulator trips and a cross-cover leakage problem on the buffer helium dryer due to EV-21352 leakage. This leakage was identified on July 7,1980, and EV-21352 was disassembled and repaired on July 8, 1980.

CORRECTIVE ACTION:

Reactor power was reduced, resulting in lower average core outlet temperatures and operation in accordance with LCO 4.2.10 and LCO 4.2.11.

The buffer helium dryer valve EV-21352 was repaired to reduce the cross-tower leakage and resulting moisture ingress.

No further corrective action is anticipated or required.

REPORTABLE OCCURRENCE 80-36 ISSUE O Page .', of 3 Prepared By: Ja 8, Asa B. Reed Technical Services Technician Reviewed By: #,4+ / Vb J. ii. Gahm Technical Services Supervisor Reviewed By: )i' A Frank M. Mathie Operations Manager Approved By: MA 0'Y N Don tiarembourg d/

Manager, Nuclear Production

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