ML17252A868
| ML17252A868 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 04/27/1973 |
| From: | Caldwell W Consolidated Edison Co of New York |
| To: | O'Leary J US Atomic Energy Commission (AEC) |
| References | |
| Download: ML17252A868 (2) | |
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William E. Caldwell *. Jr.
Vice President.
Consolidated Edison Company of New York. Inc.
4 Irving Place. New York. N Y 10003 Telephone {~12) 460-5181 Mr. John F. O'Leary, Director Directorate of Licensing
- u. s. Atomic Energy commission Washington, D. c. 20545 Dear Mr. O'Leary No. 2 The following report of an Abnormal Occurrence, previously reported by. telephone to Mr.*. Anthony Pasano, Region I.
Regulatory Operations Inspector on April 19, 1973, and by telegram to Mr. James P. O'Reilly, Director, Region I Regulatory Operq.tions Office, on April 20, 1973, is pro-vided pursuant to the requirements of Section 6.6.1.B of the Technical Specifications to Facility Operating License \\
No. DPR-26~ It should be noted that the telegram contained an error in that the paragraph reference of 6.6.l(A) should have been 6.6.l(B).
On Thursday, April 19, 1973, Unit No. 2. was being held at a temp!=!rature, pressure and boron concentration of 225oF, 450 psig and 2240 ppm, respectively, with a11*
control and shutdown.rods fully inserted. At approximately 3:45 P.M., -both doors of the 80' elevation personnel air lock were inadvertently placed in the open position due to a malfunction of the mechanical interlock device. The interlock.is designed to prevent both doors from being open at the same time. Both air lock doors were open for about two minutes. Following the 3:45 P.M. occurrence the air lock*was immediately taken out of service for a detailed inspection and repairs.
The inspection revealed that the interlock malfunction was the result of a bent door hinge shaft extension on
- each of the doors. Rough usage of the air lock has been to have caused the shaft bending. The shaft 2800
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Mr. John F. O'Leary April 27, 1973 extension carries a chain gear which opens and closes the doors upon hand wheel rotation. The bent shafts displaced the gears allowing the chains to slacken.
With the chains sl,a~k both doors.could be placed in the open position. In.the course of the failure investigation, it was discovered that a similar inci-dent had occurred earlier the same day at 10:00 A.M.
Repairs consist~d of straightening the shaft extensions and realigning the chains. The air lock was then returned to service. To.prevent recurrence, an investigation is being conducted to provide addition~l protection against rough usage for both the 80' and 95' elevation air locks.
Until this investigation has been completed, a daily check of the interlock's operability will be made during periods when containment access is permissible.
The Technical Specifications require that contairiment*
integrity be maintained at all times when the reactor is not in the cold shutdown condition, i.e., reactor sub-cri ti cal by at least 1% A k/k and. Tavg £: 140°F.. Al though the reactor coolant temperature at the time of both occurrences was 225°F, the reactor was shutdown by at least 12% Ok/k.
Our Nuclear Facilities Safety committee, the Chairman of which was notified of the occurrenceson April 20, 1973, has reviewed the circumstances relating to this incident and approves of the remedial action taken.
very truly yours
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