ML20084S375

AO 50-254/75-17:on 750721,traversing Incore Probe Machine Three Ball Valve Failed to Close When Detector Was Withdrawn to in-shield Position.Caused by Failure of Spring to Close Ball Valve Completely.New Valve Installed

ML20084S375
Person / Time
Site:	Quad Cities
Issue date:	07/31/1975
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Office of Nuclear Reactor Regulation
References
AO-50-254-75-17, NJK-75-389, NUDOCS 8306160708
Download: ML20084S375 (2)

Text

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m Quad-C In: rating Station Post Offic ox 216 Cordova Illinois 61242 Telephone 309/654-2241 g._._# 1 7

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NJ K-75-389 q' A 6g U6[/Vp.

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N.n AN July 31, 1975 h' s.

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Director of Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission ,

Washington, D.C. 20555

Reference:

Quad-Cities Nuclear Power Station .

4 Docket No. 50-254, DPR-29, Unit 1 j Appendix A, Sections 1.0. A.2, 3 7.D. I , 6.6.B.1.a  ;

3 i

Enclosed please find Abnormal Occurrence Report No. 50-254/75-17 for Quad- l Cities Nuclear Power Station. This occurrence was previously reported to .[

Region Ill, Directorate of Regulatory'Operatiens by telephone on July 22, (

1975 and to you and Region li t , Directorate of Regulatory Operations by )

telecopy on July 22, 1975 j

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This report is submitted to you in accordance with the requirements of i Technical Specification 6.6.B.I.a. i I

Very truly yours, }

d COMMONWEALTH EDISON COMPANY QUAD-CITIES NUCLEAR POWER STATION N /

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N.J. KalIvlanakis Station Superintendent NJK/JLS/vmb cc: Region lil, Directorate of Regulatory Operations J.S. Abel copy sert amon TN 8351;

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REPORT NUMBER: A0-50-254/75-17 REPORT DATE: July 31, 1975 .

OCCURRENCE DATE: July 21, 1975  !

FACILITY: Quad-Cities Nuclear Power Station Cordova, Illinois 61242 IDENTIFICATION:

Unit One Traversing incore Probe (TIP) mai: hine number three ball valve failed to close when ths detector was withdrawn to the in-shield position. .

i CONDITIONS PRIOR TO OCCURRENCE: a Tha unit was in the. run mode at a steady state power level of 675 MW, and 2260 MWt .

DESCRIPTION OF OCCURRENCE:

On July 21, 1975, at about 9: 15AM, the shift equipment operator withdrew TIP machine number three detector from the core to the 'hield s position. When reaching the "in-shield" position the drive motor stopped, leaving the detector in the shield but the ball valve failed to close. The control key for the shear valve was given to the control room operator by the ,

shift engineer. An entry was made into the Unit One TIP cubicie and the ball valve was tapped. The valve went closed immediately.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

Equipment Failure - The valve is solenoid operated to the open position and spring loaded to the closed position. The apparent cause of the occurrence was a failure of the spring to close-the ball valve completely.

ANALYSIS OF CCCURRENCE: ,

Tha valve was open I hour and 15 minutes. Under accident conditions with the drywell pressurize to 62 psig, if the TIP tube became severed, the flow through the open penetration would have been 72.1 SCFM. This leakage is only a fraction of the capacity of the Standby Gas Treatment System and would have been easily processed by it. There would have been no significant cmounts of radioactive materials released; thus, the public health and safety would not

h

ve be'en endangered.

CORRECTIVE ACTION:

l l The valve and operating mechanism was removed and replaced by a new valve and operator of

! new design.

A valve of'the new design has already been Installed in Unit One TIP machine number one, cnd has operated satisfactorily to date. Valves for machines two, four and five will be l replaced as the additional new valves that are on order are received.

l FAILURE DATA:

Equipment identification - The TIP ball valve is a solenoid operated ball valve as shown  !

cn General Electric drawing 112C2391P001.. .

l Previous failures of TIP ball valves have occurred. Based on the performance to date of the i

cn3 new design valve Installed, installation of the remair,Ing new valves should preclude

.further similar occ~urrences. ~

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