ML20150E066
| ML20150E066 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 11/22/1978 |
| From: | Quintenz T JERSEY CENTRAL POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20150E059 | List: |
| References | |
| NUDOCS 7812110097 | |
| Download: ML20150E066 (2) | |
Text
I Initial Telephone Date of RGport Date:
Occurrence:
November 21, 1978 Initial Written Time of Report Date:
Occurrence:
0634 OYSTER CREEK NOCLEAR GENERATING STATION FORKED RIVEF., NEW JERSEY 08731 Reportable Occurrence Report No. 50-219/78/26-lP IDENTIFICATION This event is considered to be a reportable occurrence as OF OCCURRENCE:
defined la the Technical Specifications, paragraph 6.9.2.a..(3).
CONDITIONS PRIOR
, Steady State Power Routine Shutdown TO OCCt1RRENCE:
Hot Standby Operation Cold Snutdown Load Changes During i
X___ Refueling Shutdown Routine Power Operation Routine Startup Other (Spectfy)
Operation Reactor Coolant Temperature - - 160*F.
Mode Switch in " Shutdown" Reactor vented to the drywell.
DESCRIPTION On Tuesday November 11,1978, during the performance of an 0F OCCURRENCE:
Int.egrated Primary Containment Leak Rate Test, the Torus to Reactor Building dif ferential pressure switches. ops-66A & B were found to have ruptured diaphragms.
This condition was discovered while looking for suspected fources of leakage during the per-formance 'of the.above test.
Atter closing the instrument root valves for these switches, the total leakage attributable to the l
rupture of the switch diaphragms was calculated to be approxinately 3 SCFM.
l APPARENT CAUSE Design Procedure 0F OCCURRENCE':
Manufacture X
Unusual Service Condition Installa tion /
Inc. Envirovwnental Construction Component Failure l
, Operator Other (Specify)
I The cause of this occurrence can be attributed to the fact that the differential pressure switches are rated for a maximum of 10 psid continuous and a surge pressure of 25 psid.
Containement pressure at the time of the Mscovery was 36.6 psia.
The differ-ential pressure switches are not designed to withstand the dif ferential pres:.ure to which they were :.ubjected, i
l l
l 781211dO'77 l
T Reportable Occurrence Page 2 Report No. 50-219/78/26-1P ANALYSIS OF The rupture of the diaphragms in the differential pressure OCCtJRRENCE:
switches opened a path for the release of atmosphere froca the pressure absorption chamber.
Had an accident situation occurred and fission products were carried over to the pressure absorption chamber, a release could occur from the primary containment to the reactor butIdtng.
The reactor building is designed to minimize ground level release of airborne radioactive materials, and to provide for Controlled, elevated release of the building atmosphere under accident conditions.
To prevent ground level leakage of fission products from the reactor building, subsequent to design basis accidents, the standby gas treatmient system has the capability to maintain a negaf.tve. pressure of 0.25 inches of water within the reactor building.
'The system ef fluent is processed through filters before betr.g discharged through the stack.
Leakage from the dif ferential pressure switches would have been processed through the standby gas treatment system and released through the plant stock.
CORRECTIVE The root valves for the differential pressure switches were ACTION:
closed.
Replacesrent of the switches with caes which satisfy the m a._..
.-..desiga..cr.1.t.e.ria_.gerif. fad. for the absorption,_ chamber._t,s Acing,,,,,,
investigated.
FAILURE DATA:
Manufacturer:
Dwyer Instruments. Inc.
Catalog #1637-12 0-12 inches of water (setpoint adjustment) rated at 10 psid Prepared by:
Date:
// 78 T.
Quinten i
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