05000267/LER-1980-025, Forwards LER 80-025/03L-0

Forwards LER 80-025/03L-0

ML19318D257
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/19/1980
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19318D259	List: 05000267/LER-1980-025, Forwards LER 80-025/03L-0 05000267/LER-1980-025-03, /03L-0:on 800523,during 800523-30,total Primary Coolant Oxidants Were Greater than 10 Ppm W/Average Core Outlet Temp Above 1,200 F on Six Occasions.Caused by Moisture Increase & Carbon Monoxide & Dioxide Combination
References
P-80164, NUDOCS 8007080268
Download: ML19318D257 (8)

LER-1980-025, Forwards LER 80-025/03L-0

Event date:
Report date:
2671980025R00 - NRC Website

text

{{#Wiki_filter:. '~ " puNic Service Company *f Odlendo () 16805 ROAD 19% ,,_. w PLATTEV1LLE, COLORADO 80651 i June 19, 1980 Fort St. Vrain Unit No. 1 P-80164 Mr. Karl V. Seyfrit, Director Nuclear Regulatory Commission Region IV Office of Inspection and Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 Reference: Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/ 80-25, Final, submitted per the requirements of Technical Specification AC 7.5. 2(b) 2. Also, please find eclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/80-25. Very truly yours, Waren Don Warembourg / Manager, Nuclear Production DW/cls Enclosure i cc: Director, MIPC l 4 O O I 5 800708o 2 4 7 3

. W.. OCCtJRRENCE REPORT DISTRIBUTION Number of Copies De pa r tment o f Ener gy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter) San Francisco Operations Of fice Atta California Patent Croup 1333 Broadway Oakland, California 94612 Department o f Energy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter) Office of Nuclear Engineering Programs Washington, D.C. 20545 Departamat of Energy - - - - - 1 (P Letter) Mr. Glen A. Newby, Chief HTR Branch . Division of Nuclear Power Development Mail Station 5-107 Washington, D.C. 20545 De p ar tmen t o f E ne r gy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter) Attn Senior Program Coordinator P. O. Box 81325 San Diego ' California 92138 Mr. Karl V. Seyfrit. Director 1 (original of P Letter Region IV and Copy of LER) Of fice of Inspection and Enforcement Nuclear Regulatory Commission 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 7601: Di r e c to r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter, LER) Office of Meengement Information and Program Control U. S. Nuclear Regulatory Commission Washington, D.C. 20555 W. Bushnell, Site 2tanageF -

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--- 10 (original of FPLC Letter Canaral Atomic Company plus Two Copies. One P. O. %x 426 Copy of P Letter, One Plattaville, Colorado 80651 Copy of LER)

NRC Basioent Site Inspector 1 (P Letter, LER)

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REPORT DATE: June 19. 1980 REPORTABLE OCCURRENCE 80-25 ISSUE O OCCURRENCE DATE: May 23.1980 Page 1 of 6 q l FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 191/2 PLATTEVILLE, COLORADO 80651 REPORT No. 50-267/80-25/03-L-0 Final ) IDENTIFICATION OF OCCURRENCE: During the period from May 23, 1980, through May 30, 1980, total primary coolant oxidants (the sum of water, carbon monoxide, and carbon dioxide) were greater than ten parts per million with average core outlet temperature above 1200*F on six separate occasions. These events constitute operation in a degraded mode of LCO 4.2.10 and are reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2. 1 EVENT

DESCRIPTION

4 On six occasions between May 23, 1980, and May 30, 1980, the plant was oper-ated in a degraded mode of LCO 4.2.10. These occurrences correspond to the numbered shaded areas on Figure 1 (see attached) and constitute three sepa-rate events, as described below. Event #1 (Occurrence #1) On May 23, 1980, with the plant operating at approximately 52% thermal power and 145 MEe, total primary coolant oxidants were following a generally decreasing trend. At the 1000 hour readings, total oxidants had dropped to less than 10 ppm, and reactor power was increased to facilitate increased electrical generation. By 1400 hours, average core outlet temperature was greater 6han 1200*F, and total oxidants were still less than 10 ppm. However, the next four oxidant readings were greater than 10 ppm due to a slight increase in primary coolant moisture concentration. By 0000 hours on May 24, 1980, moisture con-i centration was zero ppm and total oxidants had dropped to 8.8 ppm, ending this period of LCO 4.2.10 degraded mode operation. Event #2 (Occurrence #2 and #3) I On May 27, 1980, with the plant operating at approximately 66% thermal power and 190 MWe, two instances of LCO 4.2.10 degraded operation ( c-curred. Total primary coolant oxidants had been less than 10 ppm sluce 0000 hours on May 24, and reactor power had been gradually increased to approximately 66%.

REFORTABLE OCCURRENCE 80-25 ISSUE O Page 2 o f 6 EVENT

DESCRIPTION

(Cont' d) Event #2 (occurrence #2 and #3) (Cont'd) Beginning at approximately 0200 hours on May 27, a slight increase in carbon monoxide values was observed. Although the maximum increase was less than 2 ppm, it was sufficient that total primary coolant oxidant levels at the 0600 and 1200 hour readings were slightly greater than 10 ppm. (Refer to Figure 1, shaded area 2 and 3 for Event #2 of LCO 4.2.10 degraded mode operation). By 1400 hours, total oxidants were once again less than 10 ppm, and remained at less than 10 ppm for the remainder of the day. Event #3 (Occurrence #4 #5 and #6) With the exception of the 0800 and 1400 hour readings on May 29, 1980, the plant was operated in a degraded mode of LCO 4.2.10 from approxi-mately 1300 hours on May 28 to 1000 hours on May 30, 1980. Following Event #2 degraded mode operation, total primary coolant evidant values had maintained a level trend at slightly less than 10 ppm. At the 1400 hour reading on May 28, with the plant operating at approximately 67% thermal power and 194 MRe, total primary coolant oxidant value had exceeded 10 ppm. Moisture concentration had been zero ppm since May 24, 1980, but increasing trends of carbon monoxide and carbon dioxide were sufficient to result in a total oxidant value of 10.8 ppm at 1400 hours. Except for isolated readings of less than 10 ppm at 0800 and 1400 hours on May 29 (due to a slight dip in observed carbon monoxide corcentration at these times), total primary coolant oxidants remained greater than 10 ppm. Total oxidants reached a peak value of 18.7 ppm at 0400 hours on May 30, 1980, and began a decreasing trend; however, at 0745 hours a decision was made to reduce core outlet temperature to less than 1200*F to restore compliance with LCO 4.2.10. At the 1000 hour reading, total oxidants were approximately 12.1 ppm and core outlet temperature was less than 1200*F. No further operation in LCO 4.2.10 degraded mode 4 was observed.

CAUSE

DESCRIPTION: Event #1 Four consecutive two-hourly readings of 2.3 to 2.9 ppm moisture resulted in total primary coolant ox1 dant readings of greater than 10 ppm. There is no indication that an actual moisture ingress occurred.

REPORTABLE OCCURRENCE 80-25 ISSUE O Page 3 of 6

CAUSE

DESCRIPTION: (Cont'd) Event #2 An increasing trend it 0 values on May 27, 1980, although slight, resulted in two brief peaks of operation with primary coolant oxidants greater than 10 ppm. Event #3 Both carbon monoxide and carbon dioxide began an increcsing trend on May 28, 1980, which resulted in three separate time periods of LCO 4.2.10 degraded mode operation. This increasing trend is attributable to oxidant off-gassing as a result of residual moisture reacting with the core graphite at higher reactor power levels and core outlet temperatures. CORRECTIVE ACTION: Event #1 A drop in primary coolant moisture concentration indication to zero ppm at 0000 hours on May 24 resulted in a total oxidant value of less than 10 ppm, thus restoring compliance with LCO 4.2.10. Event #2 Readings following the two brief peaks of oxidants to greater than 10 ppm were within LCO 4.2.10 limits. No specific corrective action was taker.. Event #3 A decrease in reactor power resulted in an average core outlet temperature less than 1200*F, thus ending Event #3 of LCO 4.2.10 degraded mode operation. No further corrective action is anticipated or required.

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REPORTABLE OCCURRENCE 80-25 ISSUE O Page 6 of 6 i Prepared By: ,5TA.,_ 't ;eI, Cathy C./flirsch Technical Services Technician /./l/// / fW/nu Reviewed By: ,_. / j. u. cahm J/ Technical Services Supervisor Reviewed By: 2. Frank M. Mathie Operations Manager

1. d, Approved By:

a Don Warembourg / Manager, Nuclear Production }}