ML19309H631

LER 80-021/01T-0:on 800425,combinations of 3A Target Rock Valve & 3B,3C & 3E Electromatic Relief Valves Failed to Open at Rated Reactor Pressure.Caused by Improper Bolted Air Operator,Pilot Valve Problems & Jammed Cutout Switch

ML19309H631
Person / Time
Site:	Dresden
Issue date:	05/08/1980
From:	Speroff R COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19309H627	List: ML19309H626 ML19309H631
References
LER-80-021-01T, LER-80-21-1T, NUDOCS 8005130575
Download: ML19309H631 (3)

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EVENT DESCRIPTION AND DROBABLE CONSEQUENCES @

o:2i lDuring startup follocag refueling outage. combinations of the 3A Targe: Rock Valve l c 13 I land 33, 3C and 3E Electromatic Relief Valves f ailed to open at rated reactor pressure 1 o 3, ; iwhile performing operability surveillance in six unsuccessful startup attemots. I o isI iMinimal effect on public health and safety because HPCI system i= mediately proven j c is I loperable and orderly shutdown initiated in each event. Similar event: R.O. 77-078/ l ci7j l03L-0. l atel! l 8C 8 9 SYSTE M CAUSE CAUSE COMP. VALVE CODE CODE SUSCODE COMPONENT CODE SUSCoDE SUSCODE ois!

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33 35 40 4 43 44 47 l CAUSE DESCRIP' ton AND COARECTIVE ACTICNS j

,oj l 3A Target Rock had an i= properly bolted air operator, 3B electromatic had various l )

, , , , ; pilot valve problems, 3C electrc=atic had a ja=med cutout switch on the solenoid ceils.[

, , , , and 3E electromatic had pilot valve out of adjustment and blocked pilot discharge line.)

,,,, l All problems finally corrected ' nd a each valve successfully operated at rated reactor l

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AT"'ACuMENT TO LICENSEE EVEW ?HORT 80-21/01T-0 CO3010NWEAL H EDISON CO36ANY (CWE)

DRISDEN UNIT ILDRS-3 DOCIGT # 050-249 .

During initial startup on April 25, 1980, following the refueling outage, the 3A Target Rock and the 3E Electromatic Relief Valves failed to open at rated reactor pressure while performing a relief valve operability surveillance.

All other electromatic relief valves operated successfully. All of the relief valves had operated correctly at 300 psi reactor pressure prior to reaching rated pressure. HPCI was immediately proven operable and an orderly shutdown comenced.

Subsequent inspection of the Target Rock revealed missing nuts on the air opera-tor. Since the air opertter was not attached- properly to the valve, actuation was not possible. 3e problem was corrected by properly bolting the operator on the .

valve. The 3E Electromatic was found to have the leak off line restricted by the gasket. The gasket was replaced.

Unit startup was again attempted. All relief valves successfully functioned at 250 psi reactor pressure. The 3B and 3E Electromatics failed to open at rated reactor pressure during the surveillance en 4-26-80. All of the remaining relief valves operated successfully. HPCI was proven operable and an orderly shutdown was begun. Pressure was dropped to about 200 psi. Adjustments were made to the pilot valves, and the valves functioned correctly at 450 psi reactor pressure. Reactor pressure was increased to the rated pressure, and the relief valves were tested.

The 3B valve failed to open again. The unit was brought to a cold shutdown as required by Technical Specifications. The 3B valve was repaired by replacing the pilot valve gasket and adjusting the stroke of the adjustment ar= of the pilot valve.

Unit startup was again atte=pted. All of the relief valves were operable at 300 psi reactor pressure. However, the 3B Electromatic relief valve failed to open at the rated pressure on 4-28-80. All other relief valves functioned successfully.

HPCI was i= mediately proven operable and an orderly shutdown coc=ienced. The 3B valve was exa=ined, and the pilot valve mechanis= vas replaced with a new pilot assembly whose disk to stem clearance gave greater effective pilot valve stroke.

Unit startup begun. All of the relief valves functioned correctly at 400 psi reactor pressure. The 3B Electromatic failed to open at rated pressure during the operability surveillance on 4-29-80. HPCI was 1:nciediately proven operable and an orderly shutdown comenced. The entire 3B Electromatic Relief valve was replaced to correct the problem.

Starup was begun and all relief valves were functional at low pressure. However, 3B and 3C Electromatic Relief Valves failed to open at rated reactor pressure. All remaining relief valves were operable. HPCI was imediately proven operable and an orderly shutdown comenced. The 3C Electromatic was found to have a binding cutout switch for the solenoid coils. Necessary cleaning and adjusting was performed e

to provide proper clearances on all electromatic solenoids. The 3B valve was reexa=ined, measurements made, pilot valve readjustments made, dis-charge line aligned with one of the discharge ports, and a final corrective measure was made, as suggested by the Dresser Representative, consisted of changing the pilot valve bleed off discharge line from 3/4" to 1" diameter.

Unit str.rtup begun and all valves were successfully tested on May 3, 1980. There was mini =al effect on public health or safety because the HPCI system was immediately proven operable in all cases, and an orderly shut-down initiated. Improved valve design and system configurations are being evaluated and will be implemented at the next refueling outage if deemed necessary.

The 3A Target Rock modcl number is 67F and the Dresser Electroma ic Relief valves :nodel numbers are 1525VI.