05000267/LER-1982-026, Forwards LER 82-026/03L-0.Detailed Event Analysis Encl

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Forwards LER 82-026/03L-0.Detailed Event Analysis Encl
ML20055B741
Person / Time
Site: Fort Saint Vrain Xcel Energy icon.png
Issue date: 07/14/1982
From: Warembourg D
PUBLIC SERVICE CO. OF COLORADO
To: Jay Collins
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20055B742 List:
References
P-82253, NUDOCS 8207230229
Download: ML20055B741 (5)
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LER-1982-026, Forwards LER 82-026/03L-0.Detailed Event Analysis Encl
Event date:
Report date:
2671982026R00 - NRC Website
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public servlee company ce Odondo s

16805 Road 19 1/2, Platteville, Colorado 80651-9298 July 14, 1982 Fort St. Vrain Unit No. 1 P-82253

'3@MD\\V/MM 3,

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. 50-267/82-026, 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. 50-267/82-026.

Very truly yours,

/&

    1. W Don Warembourg Manager, Nuclear Production DW/cls Enclosure cc:

Director, MIPC

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1 (P Letter)

San Francisco Operations Of fice Atta: California Patent Group 1333 3 roadway Cakland, Calif o rnia 94612 De p a r t m n t o f En e r gy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

1 (P Letter)

Mr. Glen A. Newby, Chief HTR Branch Division of Nuclear Powe r Developemat Mail S tation 3-107 Washin gton, D.C.

20543 De p a rt men t o f E n e r gy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

1 (P Letter)

Atta : P roj e ct Man a se r 110 West A S t ree t.

Suite 460 San Die go, California 92101

!!r. Jona I. Collins, Re gional Ad-dnis trator - - - - - - - - - - - - - - - - --

(Original of P Letter)

Region IV Nuclear Regulatory Ccenission 611 Ryan Plaza Drive S ui te 1000 Arlin gt on, Te xas 76011 Mr. Ge o r ge Ku:: / c z - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

1 (P Letter)

Nuclear Regulatory Co-21ssion 7920 Norfolk Avenue Be thesda, Marvland 20034 Director------------------------------------

1 (P Le t te r)

Of fice of "anagerwat Information and Pr: gram Con trol Naclear Re gulatory Co=nission Wasningten. D.C.

20535 Re c o r ds Ce n t e r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

1 (P Letter)

Ins titute of Nuclear Pewer Operations 1920 Water Place Atlanta, Georgia 3033)

Mr. Richard Phelps, FSV, GA, S i te Re p re sen t a ti ve - - - - - - - - - - - - - - - -

1 (P Letter)

Ceneral Atomic Campany 16 864 We ld Co unty Rc ad 19 1/ 2 P latteville. Colorado 80651 NRC Resident Site In s pe c to r --------------- - - - - - - - - - --

1 (P Letter) 1

REPORT DATE:

July 14, 1982 REPORTABLE OCCURRENCE S2-026 ISSUE O OCCURRENCE DATE:

June 15, 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. 50-267/82-026/03-L-0 Final B

IDENTIFICATION OF OCCURRENCE:

During-the period June 15, 1982, to June 25, 1982, the plant was,

operated in a degraded node of LC0 4.2.10 on two occasions.

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

EVENT

DESCRIPTION

Event #1 At approximately 0745 hours0.00862 days <br />0.207 hours <br />0.00123 weeks <br />2.834725e-4 months <br /> on June 15, 1982, during a normal plant startup, the reactor was increased in power and the average core outlet temperature increased above 1200 degree: fahrenheit. At this time, the total primary coolant oxidants (the sum of carbon monoxide, carbon dioxide, and water) was greater than 10 parts per million l

(ppm).

Operation continued under these conditions until 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> l

on June 23, 1982, w'ren the oxidant concentration had reduced to l

10 ppm.

Tha highest concentration reached was 44.7 ppm at 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br /> ode of LCO'4 b.

l l

Event #2 At approximately 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> on June 24, 1982, with the reactor at power (approximately 70%) and average core outlet temperature greater than 1200 degrees fahrenheit, total primary coolant oxidant.

l concentration again exceeded 10 ppm.

This degraded mode of LC0 4.2.10 persisted until 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br /> on June 25, 1982, when the concentration was reduced to 9.2 ppm. Within the 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> of this

event, the maximum concentration reached was 21.4 ppm at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on June 25, 1982.

REPORTABLE OCCURRENCE 82-026 ISSUE O Page 2 of 3

CAUSE

DESCRIPTION:

Events #1 and #2 The probable cause for the high oxidant levels is a transient which occurred on June 5, 1982, when the plant experienced a loss of three 480 volt essential busses (reference:

Reportable Occurrence 82-024-03-L-0).

Upon this loss of the essential busses; the normal bearing water supply to the helium circulators was lost, resulting in the introduction of emergency backup bearing water via the gas pressurized bearing water accumulators.

Upon actuation of the accumulators, the sudden pressure surge may have caused a small amount of water to ingress into the prestressed concrete reactor vessel via the helium circulator shafts.

The reactor was manually scrammed upon loss of the essential busses and was being brought back to power and higher temperatures when the total oxidant concentration increased beyond the 10 ppm limit of LCO 4.2.10.

As the average core outlet temperature increased above 1200 degrees fahrenheit, off-gassing of this moisture caused an increase in the carbon monoxide and carbon dioxide concentrations.

As power and temperatures settled

out, off gassing continued while the primary coolant purification trains were being utilized to remove oxidants.

CORRECTIVE ACTION:

Events #1 and #2 In both events, the total oxidant concentration was reduced below the LC0 4.2.10 limit by utilization of the primary coolant purification trains.

No further corrective action is required or anticipated.

I r

. ~

n REPORTABLE OCCURRENCE 82-026 ISSUE 0 Page 3 of 3 Prepared By:

Owen J. C' ton Q

Technical ervices Technician Reviewed By:

M [N Charles Fuller Technical Services Egin ering Supervisor

/

Reviewed By:

/

Edwi n D. /di ll" '

Station Manager

[!g1/m Approved By:

////

j

/

Con Wareinbourg'

' ' ' ~ '

Manager, Nuclearf oduction

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