ML19317F372

Unusual Event 287/75-12:on 751105,personnel Hatch Inner Door Gasket Failed.Caused by Inner Door Unseating Due to Test Pressure.Inner Door Gasket Replaced & Hatch Tested 751112

ML19317F372
Person / Time
Site:	Oconee
Issue date:	12/05/1975
From:	DUKE POWER CO.
To:
Shared Package
ML19317F366	List: ML19317F365 ML19317F372
References
RO-287-75-12, NUDOCS 8001140624
Download: ML19317F372 (1)

Text

.

n. - . - , . .- _ . . - , - . _ _ . . . _.

.g . 3 w

,m .

^

flf e, .1-DUKE POWER. COMPANY x  ; ,

~ %-

.,,m ~ OCONEE NUCLEAR STATION- -

e g4%w..,f]? g00'h, .:.ir;;; M .

g" .

- Report No.~:1 UE-287/75-12~

$ (Report Date: . December l5, 1975: .a a w. .m  ; d,. p g7( '

k. .& ..

i Event Date:- ! November 5,- 1975 '

' Facility: LOconee UnitV3, Seneca,; South' Carolina .

Identification of-Event: Failure of gasket.'on personnel hatch inner daor Conditihns Prior to Event: .Uniti at .95% full power

~

- Description'of Eventi.^

b P 60n No' v ember.5,51975b a' leak rate' test was performed on Oconee Unit 3

.. personnel sitch. ;After pressurizing the hatch to 50 psig,s it was observed .

. that theLinner; door gasket had failed. . Further testing was immediately J discontinued, and the outer personnel hatch door.was locked in the closed position.

Apparent'~Cause of Event:'

-The personnel _hatchileak rate test is performed by pressurizing.the area .

4 1between the'innerfand outer' doors. - The. test tends to unseat the inner door;

.therefore. strongbacks'are placed on.the' hatch' side of the inner door to

-maintain the door:.in a; closed condition.- The apparent cause of this incident

~

was the unseating of the inner' door by.the test pressure, resulting in failure ofLtheigasket.

. Analysis of Event:

?The. failure of the personnel hatch inner door gasket resulted'in the loss of' Lintegrity-;of theLinner door. .However, it'is highly probable that this: door.

would;have functioned properly during a loss-of-coolant' accident since ~

-contninment pressure.tends to seat the inner door, compressing the' gasket.

Addit'ionally,; the outer door .is: capable.of maintaining containment -integrity.

( Itsisiconcluded that!the health and safety of the.public was not affected.

iCorrective Action:?

iThei personnel hatch outer ' door was locked clcsed, pending approval'of- a change -

to.0coneelTechnical' Specific'ation'3.6.4. This change was received on

~

~

~

. November)11,-.1975 and: permitted:the outer door toLbe opened during power operation:for a maximum ten-minute' interval.to permit access.for= repair of.'

- (the faulty 31anerfdoor: gasket.. The inner door gasket was replaced, and'the fhatch successfully.. tested'on November' 12,[1975. .

0

-Ne..

9 4 .

'd

'_"E_

'm..

?

, k  % j _

9 i T 'rN[ r/ m- p- b et e a w 1 + e -a ^e .e --se - s' e-n--S g' er 4 W f'P*' ti " rW " ' ' *9%"'P' f