05000267/LER-1982-023, Forwards LER 82-023/03L-0.Detailed Event Analysis Encl

Forwards LER 82-023/03L-0.Detailed Event Analysis Encl

ML20063D402
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/24/1982
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20063D406	List: 05000267/LER-1982-023, Forwards LER 82-023/03L-0.Detailed Event Analysis Encl
References
P-82219, NUDOCS 8207020176
Download: ML20063D402 (4)

LER-2082-023, Forwards LER 82-023/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2672082023R00 - NRC Website

text

{{#Wiki_filter:. . public servlee company ce ceBonda 8 16805 Road 19 1/2, Platteville, Colorado 80651-9298 June 24, 1982 Fort St. Vrain Unit No. 1 P-82219 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. 50-267

Dear Mr. Collins:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/82-023, 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. 50-267/82-023.

Very truly yours, lYb Q// Don Warembourg Manager, Nuclear Production h[

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r REFORT DATE: June 24, 1982 REPORTABL2 OCCURRENCE 82-023 ISSUE 0 OCCURRENCE DATE: May 27, 1982 Page 1 of 3 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651-9298 REPORT NO. 50-267/82-023/03-L-0 Final IDENTIFICATION OF OCCURRENCE: During the period May 27, 1982, to June 4, 1982, 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 DESCRIPITON: Event #1 At approximately 1300 hours on May 27, 1982, the reactor was operating at power with average core outlet temperature greater than 1200 degrees fahrenheit. At this time, th2 total primary coolant oxidants (the sum of carbon monoxide, carbon dioxide, and water) increased above 10 parts per million (ppm). Operation continued i under these' conditions until 0100 hours on May 28, 1982, when the total oxidant concentration had decreased to 9.0 ppm. This event i constitutes operation in a degraded mode of LC0 4.2.10. Event #2 At approximately 2100 hours on May 28, 1982, with the reactor operating at power, and average core outlet temperature greater than 1200 degress fahrenheit, the total primary- coolant oxidant concentration again exceeded the limits of LCO 4.2.10. This condition persisted until 0230 hours on May 30, 1982, when the average core outlet temperature decreased below 1200 degrees fahrenheit, making LCO 4.2.10 no longer applicable. The maximum concentration reached was 46.9 ppm at 2035 hours on May 29, 1982. 4 i

REPORTABLE JCCURRENCE 82-023 ISSUE O Page 2 of 3 Event #3 At 1345 hours on May .31, 1982, while at power operation, the average core outlet temperature increased to greater than 1200 degrees fahrenheit with total primary coolant oxidants greater than 10 ppm. This degraded mode of LCO 4.2.10 continued until 2200 hours on-June 4, 1982, when the average core outlet temperature decreased below 1200 degrees fahrenheit after a single loop shutdown. Maximum concentration reached was 49.2 ppm total oxidants at 1200 hours on ' June 2, 1982. CAUSE DESCRIPTION: The reactor plant had been in a shutdown or low power operating condition over a five month period for a major system modification outage. During this period, the prestressed concrete reactor vessel had been at subatmospheric _ pressure several times for various activities. These conditions allowed for a gradual buildup of oxidants within the primary coolant and adsorption into the core graphite. Subsequent rise-to power and continued operation at high power levels / temperatures caused off gassing of the moisture and other oxidants from the core graphite and insulating boundaries. The concentration of the oxidants from off gassing resulted in these three events. CORRECTIVE ACTION: Event #1

A reduction of total primary cociant exidants below 10 parts per i million (ppm) ended the operation in a degraded mode of LCO 4.2.10.

The reduction was due to maintaining a constant power level while the IB purification train removed tha oxidants from the primary coolant system. Event #2 Event #2 ended at 0230 hours on May 30, 1982, when reactor power was reduced to decrease the core average outlet temperature to below 1200 degrees fahrenheit. Event #3 Event #3 ended at 2200 hours on June 4, 1982, when reactor power was reduced following a single loop shutdown. This power reduction resulted in the average core outlet temperature being lowered below 1200 degrees fahrenheit.

n REPORTABLE OCCllRRENCE 82-023 ISSUE O Page 3 of 3 i Prepared By: en -s Owen J.

                                  .bed b ton Technical ervices Yechnician Reviewed By:         b ,/b'      '

Charles Fuller Technical Services Engineering Supervisor l J $

                                             /

Reviewed By: z. Edwin/Ek]Ffi1 P ' ~ Station Manager Approved By: Wtutedw Don Waremcourg / Manager, Nuclear Pro (uction l l 1 i }}