ML19317F028
| ML19317F028 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 11/29/1974 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19317E999 | List: |
| References | |
| NUDOCS 8001080730 | |
| Download: ML19317F028 (2) | |
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Duke Power Company Oconee Unit 3 Report No: A0-287/74-9 Report Date:
November 29, 1974 Occurrence Date: November 14, 1974 Facility:
Oconee Unit 3, Seneca, South Carolina Identification of Occurrence: Personnel hatch gasket failure Conditions Prior to Occurrence: Unit at 40 percent full power.
Description of Occurrence:
The personnel hatch leak rate test was performed on Ocanee Unit 3 on November 14, 1974. In the performance of the test, a strongback is installed on the outside of the inner door as the test pressure, intreduced between the doors of the hatch, tends to unseat the inner door.
The outer door seats with pressure.
At an indicated pressure of 61 psig, a loud noise was heard within the hatch and the pressure began to decreast indicating an inner door gasket failure.
Maintenance personnel transitted the outer door, closed it, and made repairs to the inner door gasket. Oconee Technical Specification 3.6.4 allcws continued operation during maintenance of the personnel or emergency hatches; however, it specifies that the remaining door of the affected hatch shall be closed and sealed.
This was not possible due to the presence of the strongback on the inner door.
Designation of Apparent Cause of Occurrence:
The failure of the inner door gasket was crused by the knife edge of the door being off center of the gasket.
The door hinge was shl=med to correct the door alignment.
Personnel responsible for this test improperly. interpreted Technical Specifica-tion 3.6.4.
Since the Specification allows provisions for replacing failed gaskets while the unit is at power, it was assumed that momentary personnel passage through the outer door was permissible. Repair of the gasket, and certification testing is not otherwise possible.
Analysis of Occurrence:
The personnel hatch is designed to provide containment integrity when required.
Each door is mounted to seal with Reactor Building pressure.
The personnel hatch leak rate test introduces pressure between the doors which seats the outer door and tends to unseat the inner door.
The misalign=ent of the inner door allowed the gasket to shift under pressure.
In all likelihood, pressure from the Reactor Building side would have sealed the inner door.
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Containment integrity was maintained using the outer door of the hatch except for the short period of time necessary for personnel passage.
The probability of the need for containment integrity during the short passage time through the personnel-hatch is considered negligible.
It is concluded that the health and safety of the public was not affected.
Corrective Action:
The personnel hatch inner door has been repaired and the hatch has successfully completed the requirements for the leak rate test.
Personnel have been made aware of the proper interpretation of Technical Specification 3.6.4.
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