05000267/LER-1982-020, Forwards LER 82-020/03L-0.Detailed Event Analysis Encl

Forwards LER 82-020/03L-0.Detailed Event Analysis Encl

ML20054G779
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/15/1982
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20054G780	List: 05000267/LER-1982-020, Forwards LER 82-020/03L-0.Detailed Event Analysis Encl
References
P-82190, NUDOCS 8206220294
Download: ML20054G779 (4)

LER-2082-020, Forwards LER 82-020/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2672082020R00 - NRC Website

text

, i public Service Company F Cderado

• 16805 Road 19 1/2, Platteville, Colorado 80651-9298 June 15, 1982 Fort St. Vrain Unit No. 1 P-82190 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. 50-267/82-020, 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. 50-267/82-020.

Very truly yours, ihlp ('c;; j L . 4. - -

1 73 t

l ll '

> ,1 E ' 0 5 h WwJ, 1 Don Warembourg Manager, Nuclear Production DW/cls Enclosure cc: Director, MIPC 'g h

4 8206220294 820615 PDR ADOCK 05000267 S PDR

7

. i REPORT DATE: June 15. 1982 REPORTABLE OCCURRENCE 82-020 ISSUE O OCCURRENCE DATE: May 17. 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. 50-267/82-020/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

With the reactor operating at approximateiy 40% power, and the prestressed concrete reactor vessel (PCRV) pressurized greater than 100 psia, conditions were present which could have allowed certain interspaces between the primary and secondary penetration closures to be at a pressure less than or equal to primary system pressure. This condition constitutes a degraded mode of LCO 4.2.7(c) and is reportable per AC 7.5.2(b)2 of the Tecnnical Specifications.

EVENT DESCRIPTION:

On May 17, 1982, at 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br />, a trace of airborne contaminants was detected in the Reactur Building. Upon investigation, the source was found to be a leaking fitting on a pressure differentiai indicator (PDI-11258) between the purified helium heacer which supplies helium to the high temperature filter absorber penetrations and the helium storage system. The airborne contaminants were analyzed to be noble gases which indicated a small amount of primary coolant was leaking backwards from the penetrations. It was determined that the normal helium supply path through the purification system had a reduced flow due to " icing" in the on-line purification train (train A). "1cing" j is caused by a buildup of impurities within the low temperature I absorber in the purification train which restricts the flow. The

other purification train was available but was completing a l

regeneration cycle. As soon as the trouble was identified, bypass valves were opea.J to provide acditional helium makeup from the high pressure storage bottles to help pressurize that portion of the purified helium header which had experienced in-flux of primary coolant. At 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />, the airborne contaminants (no maximum permissible concentrations were exceeded) were dissipating. Since the airocrne contaminants indicated a presence of primary coolant, it is assumed that the primary and secondary penetration interspaces were allowed to reach a pressure less than or equal to primary coolant pressure. This condition is a degraded mode of LCO 4.2.7, Section (c), and is reportable per AC 7.5.2(b)2 of the Technical Specifications.

,1 l REPORTABLE OCCURRENCE 82-020 ISSUE O Page 2 of 3 CAUSE DESCRIPTION:

A reduction in flow in the purified helium supply to the primary and secondary penetration interspaces allowed the penetration interspace pressure to decrease to a point which was less than or equal to primary coolant pressure. This reduction in flow was caused by a buildup of impurities within the low temperature adsorber in the "A" primary coolant purification train. .

CORRECTIVE ACTION:

Upon indication that the flow through the on-line purification train was restricted, additional helium was supplied downstream of the train from the high pressure helium storage system. At 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> on May 17, 1982, this temporary system alignment was complete, and interspace pressure was being maintained from the high pressure helium storage system. This configuration allowed maintaining the interspaces at required pressures while preparations were underway to place the second purification train on line.

On 0645 hours0.00747 days <br />0.179 hours <br />0.00107 weeks <br />2.454225e-4 months <br /> on May 18, 1982, the "B" primary coolant purification train was placed in service, and "A" train placed in regeneration.

Upon placing "B" train in service, the normal system flow path was regained, and the system lineup returned to normal.

No further corrective action is anticipated or required.

e os l

REPORTABLE OCCURRENCE 82-020 ISSUE O Page 3 of 3 Prepared By: >' u w t. >L.a Owen Technica J. G ytonServices(4 ecnnician l

O Reviewed By- ' b- L -- > r ' e ChaYlesfuller

-. Techttical Services rg eering Supervisor

<v Reviewed By: _ /

Edwfn'i D'. Hil1 Station Manager Approved By: ~ Ya4erM Don Warembourg [/

Manager, Nuclear Production

- - . . .