ML20215E321
| ML20215E321 | |
| Person / Time | |
|---|---|
| Site: | Berkeley Research Reactor |
| Issue date: | 02/27/1968 |
| From: | Mark H CALIFORNIA, UNIV. OF, BERKELEY, CA |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20215E220 | List:
|
| References | |
| FOIA-86-811 701, NUDOCS 8612220104 | |
| Download: ML20215E321 (2) | |
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UNIVERSITY OF CALIFORN1 ;' BERKELEY V
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SANTA DAitDAyk
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DEPARU1ENT OF NUCLEAR ENGINEERING
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Director Division of Reactor Licensing U.S. Atomic-Energy Commission
, Eat Div of Compliance Washing. ton, D.C. 20545
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Dear Sir:
.e This letter is being written in response to your request to y
report any unusual occurrences in connection with reactor operation.
In the course of the routine checkout at the Berkeley TRIGA Mark III Reactor, prior to startup on the morning of February 26, 1968, the Reactbr Operator noticed that, in the Steady-State Mode, with the transient-rod carriage raised, a ready light was lit under the transient-rod-fire button.
This implied that the transient rod M
could be fired out at an arbitrarily high operating power.
- Normally, the transient rod cannot be fired out in the Steady-State Mode.
Upon discovering the anomalous ~ situation, the Reactor Operator notified the Senior Operatoi in Charge and also the Reactor Super-p visor.
The latter ordered the checkout to be interrupted and no jh operation to take place until the source of the problemtwas deter-
'T5 mined.
The Supervisor also discussed the situation-with R. Dodds of AEC/ SAN.
The transient-rod position-indicating microswitches were first
,7 checked and found to be operating normally.
However, as soon as the
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bridge was opened for a further inspection, and the transient-rod
'l carriage raised (an interlock must be overridden to accomplish this),
the source of the trouble was apparent.
With no air behind the transient-rod piston, tho carriage was, nevertheless, picking up the 1
rod.
It was found that the force binding the rod in the carriage was a
very slight, and, indeed, scramming the rod would release it every Q,
time.
At this point, the reason for the rod binding in the carriage was notsknown, but it was speculated that it could be a small chip j
wedged bbtween the piston and the carriage, or it could be a layer 5
of rust which had formed inside the carriago - the latter effect had
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'I been observed in the past.
As soon as the top of the transient rod carriage was removed,,it was apparent that rust was indeed the culprit.. - '
A swab was used to remove the rust, which existed only in a ring 1
around the top 'of the carriage, and this served to completely return the system to normal function, j
O The Supervisor again discussed the situation with Mr. Dodds, J
and then ordered that normal operation could be resumed.
As a pre-caution against recurrence, we are instituting, as part of our monthly,5 transient-rod
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reactor checkout, a lubrication of to inside of the
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cf;.' C., W a s h i n g t o n.,
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- 2 February 27, 1968
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- -i s QP;-carriage.
r We believe that the symptoms and the remedy for this f
situation might be of interest to other TRIGA users.
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a Sincerely, Yhlt "m cQL.)
i IIans M. Mark
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Reactor Administrator l(
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cc: Members, Reactor llazards Committeo 4
L. Ruby, Reactor Supervisor d-L. S.tollar, Laboratory Manager R. bodds, AEC/ SAN k
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J. Batch, General Atomic i
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