05000267/LER-1981-069, Forwards LER 81-069/03L-0.Detailed Event Analysis Encl

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Forwards LER 81-069/03L-0.Detailed Event Analysis Encl
ML20033C876
Person / Time
Site: Fort Saint Vrain Xcel Energy icon.png
Issue date: 11/23/1981
From: Warembourg D
PUBLIC SERVICE CO. OF COLORADO
To: Jay Collins
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20033C877 List:
References
P-81297, NUDOCS 8112040449
Download: ML20033C876 (6)
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LER-1981-069, Forwards LER 81-069/03L-0.Detailed Event Analysis Encl
Event date:
Report date:
2671981069R00 - NRC Website
v • d • e

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Nuclear Regulatory Commission b.

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Reference:

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

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/81-069, 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. 50-267/81-069.

,ery truly yours,

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Ww Don Warembou Manager, Nuclear Production DW/cls Enclosure cc: Director, MIPC i

8112040449 811123

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PDR ADOCK 05000267 fr 5

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r REPORT DATE: _

November 23, 1981 REPORTABLE OCCURRENCE 81-069 ISSUE 0 OCCURRENCE DATE:

November 4, 1981 Page 1 of 5 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651-9298 REPORT NO. 50-267/81-069/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

During the period from November 4, 1981, to November 9, 1981, the plant was operated in a degraded mode of LCO 4.2.10 on three occasions.

These events are reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2.

EVENT

DESCRIPTION

Event 1

.1e Figure 1.

At 0000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> on November 4, 1981, with the average core outlet temperature reaching and exceeding 1200 degrees fah-enheit, the total primary coolant oxidants (the sum of carbon montatete, carbon dioxide, and water) was above 10 parts per mill.on

( ca.-).

Operation continued under these conditions until 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> on November 5, 1981. This event constitutes operation in a degraded mode of LCO 4.2.10.

Event 2 See Figure 1.

At 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> on November 5, 1981, with average core outlet temperature greater than 1200 degrees fahrenheit, the total primary coolant oxidants increased above 10 ppm. Operation continued unaer these conditions until 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on November 6, 1981.

This event constitutes operation in a degraded mode of LCO 4.2.10.

Event 3 See Figure 1.

At 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on November 6, 1981, with average core outlet temperature greater than 1200 degrees fahrenheit, the total primary coolant oxidants increased above 10 ppm. Operation continued under these conditions until 0406 hours0.0047 days <br />0.113 hours <br />6.712963e-4 weeks <br />1.54483e-4 months <br /> on Novemuer 9, 1981.

This event constitutes operation in a degraded mode of LCO 4.2.10.

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REPORTABLE OCCURRENCE 81-069 ISSUE O j

Page 2 of 5 i

CAUSE

l

DESCRIPTION

Event 1 i

See Figure 1.

On November 2, 1981, moisture was inadvertently introduced into the primary coolant system while the reactor was being maintained below 2% power. The primary coolant purification system was utilized tn remove the primary coolant oxidants.

Reactor power was slowly increased as the oxidant concentration trended downward. At 0000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> on November 4, 1981, the average core outlet tamperature reached and exceeded 1200 degrees fahrenheit Jith a total primary coolant oxidant concentration of about 10.7 ppm.

As the average core outlet temperature increased, the total primary coolant oxidants contih.ed to out gas from the core graphite and reached a maximum of 18.3 ppm at 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> on November 4, 1981. At 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> on November 5, 1981, the primary coolant purification syrtem had reduced the total primary coolanc oxidants below the 10 ppm limit of LCO 4.?,.10.

L Event 2 See Figure 1.

At 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> on November 5, 1981, the total primary 1

coolant oxidants exceeded the 10 ppm limit of LCO 4.2.10.

As reactor i

power was increased from 67.6% at 0000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> to 86.1% at 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br /> on November 5, 1981, the average core outlet temperature increased to j

1391 degrees fahrenheit.

Due to residual moisture in the core, several spikes in the total oxidants' level occurr9d as the core continued to out gas.

The peak levels of 12.1 ppm were reached on f

2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br />, November 5, 1981, and 0600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br />, November 6, 1981.

At 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on November 6, 1981, the total primary coolant oxidants fell beluw the 10 ppm limit of LCO 4.2.10.

Event 3 See Figure 1.

As core temperature fluctuation testing (RT-500K) continued with reactor power reaching 100%, the average core outlet

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temperature increased to a maximum of 1428 degrees fahrenheit.

Increases in carbon dioxide and carbon monoxide levels due to out gassing caused total primary coolant exidants to exceed the 1

10 ppm limit of LCO 4.2.10 at 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on November 6', 1981.

This degraded mode of operation continued until 0600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br /> on November 9, 1981, when the average core outlet temperature fell below the 1200 degree fahrenheit specification of LCO 4.2.10.

During this i

period of operation in a degraded mode, the tetal oxidant concentration reached a maximum of 24.8 ppm at 0600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br /> on November 7, 1981.

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REPORTABLE OCCURRENCE 81-069 ISSUE 0 Page 3 of 5 CORRECTI'IE ACTION: _

Corrective actions to the degraded mode operations outlined in this occurrence are as follows:

Events 1 and 2 t

The primary coolant purification system was utilized to remove the-primary coolant oxidants; thereby, bringing them below the LCO limit of 10 ppm.

Event 3 The average core outlet temperature dropped below 1200 degrees fahrenheit; thus LCO 4.2.10 no longer applied.

No further corrective action is anticipated or required.

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REPORTABLE OCCURRENCE 81-069 ISSUE O Page 5 of_5 Prepared By:

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Technical Services chnician Reviewed By:

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Station Manager Approved By:

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Manager, Nuclear Production w-WM-ep-.-ww

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