05000249/LER-1974-025, Regarding Failure of B TIP Machine Valve to Close
| ML17252A506 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 08/19/1974 |
| From: | Stephenson B Commonwealth Edison Co |
| To: | James Keppler US Atomic Energy Commission (AEC) |
| References | |
| BBS Ltr.#597-74 LER 74-025-00 | |
| Download: ML17252A506 (3) | |
| Event date: | |
|---|---|
| Report date: | |
| 2491974025R00 - NRC Website | |
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CommonwAh Edison One First Na;icS'Plaza, Chicago, Illinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 BBS Ltr.11597-74
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50-249 j
Mr. James G. Keppler, Regional Director Directorate of Regulatory Operations-Region III U. s. Atomic Energy Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 sumer:
REPORT OF ABNORMAL-OCCURRENCE PER SECTION 6.6.B OF nm TECHNICAL SPECIFICATIONS.
TIP MACHINE BALL VALVE FAILURE TO CLOSE.
References: 1) Regulatory Gui~e 1.16 Rev.l Appendix A
- 2) Notification of Region III of AEC Regulatory Operations*
Telephone: F. Maura, 1415 h~urs.on August 8, 1974 Telegram: J. Keppler, 1447 hours0.0167 days <br />0.402 hours <br />0.00239 weeks <br />5.505835e-4 months <br /> o~ August 8, 1974 Report Number: 50-249/1974-:2:5 Report Date: August. 19, 1974 Occurrence Date: August 7, 1974 Facility: Dresden Nuclear Power Station, Morris, Illinois IDENTIFICATION OF OCCURRENCE The ball isolation valve on the Unit 3 B",transversing incore probe (TIP) machine failed to cl9se as is normal foll.owing the retraction of the 3B TIP probe into its shield.
CONDITIONS 2RIOR TO OCCURRENCE The ball valve bad been actuated open for the purpose of taking data with the TIP system approximately three hours prior to the observed failure.
During these three hours, the valve remained open *. *No abnormal operation of the 3B TIP machine was noted during the data taking.
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- 9 Mr; James G. Keppler r.* August 19, 1974 DESCRIPTION OF OCCURRENCE
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--- --:--- -'-------*--- --nata--fromtheUntt-3-TIP system was taken from approximately 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br /> until 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br /> on August 7, 1974.
To begin the data taking, all TIP probes.were driven out* Of their shields, and all isolation ball valves were actuated open.
Data taking proceeded normally, with no TIP machine malfunctions noted, save a position tracing problem on two traces, which was attributed to dirty contacts.
The ball valve malfunction was noted at the TIP ma~hine operating panel by mean~ of an indication light, which illuminates when the ball valve is in the open position.* The valve normally closes when the TIP probe is retrac~ed into its shield, or can be manually actuated to close. Neither
. *method was o.bserved *to work, and the ball valve was considered failed at: i910 hours** on Aug\\ist 7, 1974.
Following the obserired *malfunction, a safety related 'work request
(#7114) was issued at urgent priority. The 3B TIP machine was placed out of service; and"while workers were.in tbe TIP machine room, the entire TIP system for Unit 3 was placed out of service.
Repairs 'to the 3B TIP machine.ball isolation. valve were completed on August 9,
- 1974, and.-.the TIP system was retuined to 'servic.e.
Sub'sequentD:9peration of the TIP J!18Chines proceed~d normally.*
'APPARENT CAUSE OF. OCCURRENCE (Camponent Failure).
Examination of the failed ball valve identified a broken wire on the solenoid coil.actuator as the cause of the ~ailure.
ANALYSIS OF OCCURRENCE.
The isolation ball.valve is' part of the pri.miiry containment, in series with the isolation shear valve.
The latter actuates* under emergency
. isolatioi:i conditions, and was. *checked and found ~perable. *at the time of the repair. Thus, emergency primary containment wa_s not compromised by.the ball valve failure, and no threat to plane or pubi'ic health and safe"ty existed.
The occurrence is.directly attributed to the malfunction of the 3B TIP machine ball isolation valve and to no o.~he'r cause *.
CORRECTIVE ACTION
Repairs done to the 3B TIP machine ball isolation va~ve involved replacement of the top actuator port~on of the valve with ~ new unit.
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e Mr.* James G. Keppler J. **
August 19, 1974 FAILURE DATA
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**--------------on-Jun~I9-, I974;-3Jf-TIP machine ball isolation valve failed to close, but was inspected and found closed and successfully cycled subsequent to the apparent failure.
See deviation report no. Dl2-3-74-33, "Unit 3 TIP Ball Valve Apparent Failure".
EQUIPMENT IDENTIFICATION 580A56 Valve,. Nuclear Instrumentation, General Electric Company NID.
- ll2C239lPOOl, Ball, ior Transversing In-Core Probe.
Sincerely, BBS:JGT:do