ML20087B282

Ao:On 721027,containment Vessel Personnel Hatch Inner Door Malfunctioned.Caused by Failure of Cam Track Bearing in Inner Door Mechanism,Preventing Closure of Door.New Cam Track Bearing Installed

ML20087B282
Person / Time
Site:	Robinson
Issue date:	11/20/1972
From:	Utley E CAROLINA POWER & LIGHT CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8403090031
Download: ML20087B282 (1)

Text

~

i V '

, W"S p ;-' -

~

-d( l N Caro"na Dower a Light Company & c

%;;j/j 7

( '

ff / gl, \

November 20, 1972 ,N si.

//gp 2 .t. "hl) .,,

Mr. John F. O' Leary \ [j[')b ,3 /

Directorate of Reactor Licensing U. S. Atomic Energy Commission

'/ 9N2 C

AV I  ; N Washington, D. C. 20545 \, '

- M n_-

p H. B. ROBINSON UNIT NO. 2 50-261 LICENSE DPR-23 CONTAINMENT VESSEL INTECRITY

Dear Mr. O' Leary:

In accordance with Technical Specifications and Bases, Section 6.6.2.D, it is reported that an abnormal occurrence took place on October 27, 1972, when containment vessel integrity was broken.

At 10:25 A.M., the containment vessel personnel hatch inner door malfunctioned while two maintenance technicians were leaving the containment vessel, resulting in this door jamming open approximately four inches with the technicians in the air lock. Due td limited stay time, the containment vessel was depressurized at 10:28 A.M., a purge was initiated at 10:36 A.M.,

and the outer door of the personnel hatch was opened at 10:40 A.M. The technicians exited, and the outer door was immediately reclosed, violating containment integrity for about ten seconds.

g The inner and outer personnel hatch doors are mechanically inter .

locked to prevent simultaneous opening. A cam track bearing in the inner door mechanism failed, preventing closure of this door and, therefore, the permissive for opening the outer door could not be satisfied. With permission from Mr. Bob Schemel of the Directorate of Reactor Licensing, c~ontainment in-tegrity was momentarily broken a second time to allow maintenance personnel access to make necessary repairs. A new cam track bearing was installed, returning the interlock system to satisfactory operating conditions.

The Plant Nuclear Safety Committee has reviewed this incident,

, concurred with the actions taken, and concluded that there was necessary m justification to break containment integrity for the short duration involved.

Yours very truly, ACT:za '

E. E. Utley z- f $4 ,q '

Vice President cc: Mr. C. D. Barham - Bulk Power Supply .

Mr. N. B. Bessac /

.Mr. B. J. Furr Mr. S. Grant 8405090031 721120 PDR ADOCK 05000261 S em . , _ . . _ . . 6454:

_ , . _ . _ _ . _ i, 336 FaycitevJ;e Street . P. O. Box 1551 + Raleigh, N. C. 27502

.,_T' '

COPY SE1E REGI0F ~