05000219/LER-1981-053, Forwards LER 81-053/03L-0.Detailed Event Analysis Encl
| ML20033D301 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 11/24/1981 |
| From: | Carroll J JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20033D302 | List:
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| References | |
| NUDOCS 8112070509 | |
| Download: ML20033D301 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| 2191981053R00 - NRC Website | |
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OYSTER CREEK NUCLEAR GENERATING STATION UJJP"."$?%Aji?.'
((09)693-6000 - O. BOX 388
- FORKED RIVER
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Novanber 24, 1981 f,l\\
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<N Mr. Ponald Haynes, Director k'D
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Region I y
United States Nuclear Regulatorf Ccmnission 631 Park Avenue 3
3I King of Prussia, Pennsylvania 19406
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Dear Mr. Haynes:
SUBJECT: Oyster Creek Nuclear Generating Station Docket No. 50-219 Licensee Event Report Reportable Occurrence No. 50-219/81-53/3L This letter forwards three copies of a Licensee Event Report to report. Reportable Occurrence No. 50-219/81-53/3L in ccupliance with paragraph 6.9.2.b.2 of the Technical Specifications.
Very truly
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T. Carroll, J Acting Director Oyster Creek JIC:dh Enclosures cc: Director (40 copies)
Office of Inspection and Enforcement United States Nuclear Regulatory Ccnmission Washington, D.C.
20555 Director (3)
Office of Management Information and Program Control United States Nuclear Regulatory Ccmnission Washington, D. C. 20555 NRC Resident Inspector (1)
Oyster Creek Nuclear Generating Station Forked River, N. J.
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OYSTER CREEK NUCLEAR GDERATING STATION-Forked River, New Jersey 08731 Licensee Event Report l
Reportable Occurrence No. 50-219/81-53/3L Report Date Novenber 24, 1981 Occurrence Date October 21,1981 Identification of Occurrence The plant was operating under a limiting condition for operation as given in the Technical Specifications, Table 3.1.1 Item I.
The ability of the Offgas Syst s to autmatically isolate on an Offgas line high radiation trip or Main Steam line high radiation trip was lost for approximately 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br /> due to a broken power cable which feeds the offgas bypass valve (V-7-31).
This event is considered to be a reportable occurrence as defined in the Technical Specifications, paragraph 6.9.2.b.2.
Conditions Prior to Occurrence Major Plant Parameters:
Power:
Reactor 1198IWt Generator 398 IWe-4 Flow:
Recirculation 10.2 x lg p Feedwater 4.2 x 10 lb/hr Description of Occurrence On Wednesday, October 21, at approximately 1350 hours0.0156 days <br />0.375 hours <br />0.00223 weeks <br />5.13675e-4 months <br />, the Offgas milaing isolated and-the offgas bypass valve V-7-31 closed. When valve V-7-31 could not be rmotely opened, the plant began reducing load by using control rods and altering recirculation flow. It was disccvered that the 3" conduit containing the electrical feed for valves V-7-31 and V-7-29 (the delay. *.ine drain valve) '
had fallen frm the north external. Reactor Building wall, e.xl that several of the cables inside were broken. Valve V-7-31 was opened using a'tmporary junper, and a personnel watch was set up at this juroper in case there was the need to manually isolate the valve.. 'Ihe ocnsequences of leaving valve V-7-31 closed were evaluated, but this action would have led to a reactor isolation and subsequent turbine trip. ' A consultation between Plant Managment and the NBC' resulted in the determination that a plant shutdown should ocenence due to the inability to automatically operate V-7-31.
At approximately_1512 hours, a plant--
shutdown was cmmenced and the generator.was off the line at 1653 hours0.0191 days <br />0.459 hours <br />0.00273 weeks <br />6.289665e-4 months <br />.
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Reportable Occurren Page 2 Report No. 50-219/81-53/3L Electrical maintenance personnel worked to reestablish c_ntrol pwer to the valves using as much of the original conduit and cable as possible. By approxi-mately midnight all of the technical and safety concerns had been resolved for any changes made. At approximately 0245 hours0.00284 days <br />0.0681 hours <br />4.050926e-4 weeks <br />9.32225e-5 months <br /> on October 22 the installation and testing were cmpleted, and plant startup cmmenced at 0300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> and the generator was back on line at 0540 hours0.00625 days <br />0.15 hours <br />8.928571e-4 weeks <br />2.0547e-4 months <br />.
Apparent Cause of Occurrence The cause of the occurrence was due to the improper selection and installation of the anchor bolts which fastened the conduit to the Reactor Building wall.
Analysis of Occurrence The offgas bypass valve (V-7-31) is interlocked with the recmbiner systen inlet valves (AOV-001A and AOV-001B) and with the delay line drain valve (V-7-29).
During normal operatica one of the recmbiner inlet valves is open and the bypass is closed. During an offgas syst m malfunction, the bypass will auto-matically open to provide a flow path for the air ejectors.
The control switch for the offgas bypass valve (located in the Control Rom) has three positions:
" NORMAL", "'SOIATE AND BYPASS", and "ISOIATE".
In the " NORMAL" position control of the valve is fr a the Offgas Building.
Placing the control switch in the "ISOIATE AND BYPASS" position will close both recmbiner iltlet valves and open the bypass. In the "ISOIATE" position, the inlet valves, the bypass valve, and the delay line drain valve will all close. In the "NOPNAL" or "ISOIATE AND BYPASS" positions, the bypass valve will autmatically open when both recmbiner in)et valves are closed. Any control function frm the Control Bom will override controls frm the Offgas Building, and autmatic isolation due to a high radiation trip sicnal will override all other controls.
hhen the Offgas Systm isolated on October 21, the bypass should have opened, yet since the power was cut to the valve, the solenoid vented all air and the valve failed in the closed position. The cable for-the position indication was not damaged, so Operations personnel knew that the valve was not open. The quick installation of a tmporary junper opened the valve, and provided the necessary flow path for the air ejectors. Because this valve was quickly opened and the plant made the determination to comience a plant shutdown due to the inability to automatically isolate, the safety significance of the event is considered minimal.
Repo dable Occurrence.
. Report No. 50-219/81-53/3L
Corrective Action
Aside frcxn opening the bypass valve and bringing the plant to a shutdown condition, several other actions were taken. A personnel watch was stationed at the jumper
- - location in case the bypass valve had to be shut. The other cables contained in the failed conduit were researchod and it was found that no otlers were safety related. Control power was restored to the valve by using as much of the original cable as possible and any additional cable and boxes required (all the necessary safety evaluations were approved prior to installation and testing).
Since the failed conduit was anchored by in g eperly installed lead caulking anchors, the requirments of other safety related installations were checked.
It was determined that no other safety related systens were supported by this type of anchor. A randam sampling of anchors used on the Emergency Core Cooling System nodifications revealed that all anchors used were either the Redhead or Hilti type. When the fallen conduit was re-anchored to the wall, Hilti bolts were used. Since this type of failed anchor is used extensively in the Offgas Building, the r-ndation is being made to examine (and replace if necessary) as many anchors as possible.
Failure Data 1
Ccxuponent: Lead Caulking Anchors vf