05000267/LER-1983-005, Forwards LER 83-005/03L-0.Detailed Event Analysis Encl

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Forwards LER 83-005/03L-0.Detailed Event Analysis Encl
ML20072E014
Person / Time
Site: Fort Saint Vrain Xcel Energy icon.png
Issue date: 03/09/1983
From: Clayton O, Fuller C, Warembourg D
PUBLIC SERVICE CO. OF COLORADO
To: Jay Collins
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20072E017 List:
References
P-83093, NUDOCS 8303210546
Download: ML20072E014 (6)
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LER-1983-005, Forwards LER 83-005/03L-0.Detailed Event Analysis Encl
Event date:
Report date:
2671983005R00 - NRC Website
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Public Service Company P Collomde 16805 Road 19 1/2, Platteville, Colorado 80651-9298 fo-A67

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March 9, 1983 J

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h P-83093 Mr. John T. Collins, Regional Administrator 4

Region IV Nuclear Regulato v Commission 611 Ryan Plaza Drive SL.ce 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. 50-267/83-005, 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. 50-267/83-005.

Very truly yours, M 7VWM Don Warembourg U

Manager, Nuclear Production DW/cis Enclosure i

cc: Director, MIPC 0

S 8303210546 830309 PDR ADOCK 05000267 S

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a e-REPORTAB12 OCCURRENCE DISTRIBtTTION Number of Copies

~ DePa rtment o f Energy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P 14tter)

. San Francisco Operations Office

. ATTN: California Patent Group

1333 Broadway Oakland. California 94612 Denartaant of Energy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter)

. Mr. Glen A. Newby. Chief HTR Branch

- Division of Nuct. ear Power Development Mail Station B-107 Washington D.C.

20545 Depar tmen t o f Energy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter)

Project Manager ATTN:

Dr. Beighley P. O. Box 81608' San Diego CA 92138 e

f1(OriginalofPLetter)

Mr. John T. Collins. Regior.a1 Administrator Region IV Nuclear Regulatory Connission 611 Ryan Plaza Drive Suite 1000

. Arlington. Texas 76011 Mr. Philip C. Wagner, Project Manager 1 (P Letter)

Region IV Nuclear Regulatory Couumission 611 Ryan Plaza Drive Suite 1000 Arlington. Texas 76011 Director - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter)

Office of Management Information and Program Control Nuclear Regulatory Commission Washington D.C.

20555 INPO Records Center -------------------------------

1 (P Letter)

Suite 1500 1100 circle 75 Parkway Atlanta. Georgia 30339 Mr. Richard Phelps. PSV GA Technologies. Inc. Site Representative 1 (P Letter)

Ceneral Atomic Technologies. Inc.

16864 Wald County Road 191/2 Platteville. Colorado 80651 l

NRC Resident Site Inspector 1 (P Letter) l l

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REPORT DATE:

March 9, 1983 REPORTABLE OCCURRENCE 83-005 ISSUE O OCCURRENCE DATE:

February 7, 1983 Page 1 of 4 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651-9298 REPORT NO. 50-267/83-005/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

During the period February 7,1983, through February 15, 1983, with the reactor operating, and the average core outlet temperature between 725 and 1200 degrees fahrenheit, the reactor dewpoint exceeded limits set forth by Figure 4.2.11-1 of LCO 4.2.11 on five separate occasions. These events constitute operation in a degraded mode of LCO 4.2.11 and are reportable per Section AC 7.5.2(b)2 of the Fort St. Vrain Technical Specifications.

1 EVENT

DESCRIPTION

On January 28, 1983, the trip of a buffer helium recirculator caused an upset in the buffer helium system which allowed an ingress of moisture to the reactor vessel.

The reactor was shut down, and efforts to remove the moisture via the helium purification system commenced.

By February 5,1983, moisture levels had been reduced sufficiently to allow startup, and the reactor was taken critical.

The events described below occurred during the subsequent startup operations.

Event #1:

At approximate'ly 1420 hours0.0164 days <br />0.394 hours <br />0.00235 weeks <br />5.4031e-4 months <br /> on February 7, 1983, with the reactor at power and an average core outlet temperature near 950 degrees

- fahrenheit, the calculated reactor dewpoint entered the non-acceptable" region of Figure 4.2.11-1 of LCO 4.2.11.

This condition existed until approximately 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> the same day when the dewpoint i

returned to the " limited acceptable" region.

The highest dewpoint reached was 53 degrees fahrenheit at an average core outlet temperature of 952 degrees fahrenheit.

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w REPORTABLE OCCURRENCE 83-005 ISSUE O Page 2 of 4 Event #2:

At approximately 2140 hours0.0248 days <br />0.594 hours <br />0.00354 weeks <br />8.1427e-4 months <br /> on February 7,1983, the calculated reactor dewpoint again exceeded the limits of Figure 4.2.11-1 for the corresponding average core outlet temperature.

This condition existed until approximately 2025 hours0.0234 days <br />0.563 hours <br />0.00335 weeks <br />7.705125e-4 months <br /> on February 8, 1983.

The highest calculated reactor dewpoint was 43 degrees fahrenheit at an average core outlet temperature of 1004 degrees fahrenheit.

Event #3:

At approximately 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on February 10,.1983, the calculated-reactor dewpoint exceeded the limits of Figure 4.2.11-1 with the average core outlet temperature ranging between 725 and 1200 degrees fahrenheit.

This condition continued until approximately 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> on February 11, 1983, when the dewpoint returned to the limited acceptable region again.

The highest dewpoint attained was 17 degrees fahrenheit at an average core outlet temperature of 1041 degrees fahrenheit.

Event #4:

From approximately 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br /> on February 14, 1983, to approximately 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br /> the same day, the calculated reactor dewpoint exceeded the limits of Figure 4.2.11-1.

The highest dewpoint reached was 5 degrees fahrenheit at an average core outlet temperature of 1175 degrees fahrenheit.

Event #5:

From approximately 0200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> on February 15, 1983, to 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br /> the same day, the calculated reactor dewpoint once again exceeded the limits of Figure 4.2.11-1 for the corresponding average core outlet temperatures. The highest dewpoint reached was 5 degrees fahrenheit at an average core outlet temperature of 1190 degrees fahrenheit.

CAUSE

DESCRIPTION:

Moisture was introduced into the prestressed concrete reactor vessel as the result of a buffer helium system upset which occurred on January 28, 1983.

When subsequent startup operations commenced and primary coolant temperatures increased, the vaporization rate of the water which was present in the reactor vessel increased to a point where moisture was being entrained in the primary coolant faster than the helium purification system could remove it.

1

I REPORTABLE OCCURRENCE 83-005 ISSUE O Page 3 of 4 CORRECTIVE ACTION:

In the first four events, the helium purification system was used to reduce the reactor dewpoint to within the " limited acceptable" region of Figure 4.2.11-1 for the appropriate average core outlet temperature.

In the fifth event, the reactor was manually shutdown following an unrelated electrical system upset.

No further corrective actions are required or anticipated.

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REPORTABLE OCCURRENCE 83-005 ISSUE O Page 4 of 4 Prepared By:

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.b Owen s. (layton Q

Senior Ten nical Services Technician Reviewed By:

CPrdles Fuller Technical Services Engineering Supervisor

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Reviewed By:

Edwin D. Hill Station Manager Approved By:

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Don'Warembourg 4:f Manager, Nuclear Production

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