United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9505180280

                     The HARRISON STEEL CASTINGS CO.

                 POST OFFICE BOX 60          PHONE 317-762-2481

                          ATTICA,INDIANA 47918

March 24,1995

US Nuclear Regulatory Commission
Region III
801 Warrenville Road
Lisle, IL 60532-4351

Reference:     NRC License No. 13-02141-01, Amendment 25
Subject:       Equipment Breakdown

The Gamma Ray Department called me yesterday afternoon to report that
they noticed smoke coming from the Amersham Model 957 Automatic Exposure
controller which was installed with a model 680 Cobalt 60 projector at
our north exposure room this past December. They terminated the exposure
by manually cranking the source back into 680 projector. Our electrician
determined that a capacitor on a circuit board in the 957 had failed.
The extent of any other damage was not determined.  Amersham was
notified, and requested that we return the 957 for repair. They are to
send out a return authorization and instructions.

The radiographers asked if they could continue using the manual crank to
operate the cobalt 60 source until the 957 was actually removed for
return to Amersham. They were about half finished with a large casting
that required a rather elaborate setup. Although our license does not
specifically address this question, it was my opinion that we would not
be in violation by continuing to radiograph the casting as described.
This opinion was based on the following reasons.

     1.   The only functions that were not working normally were the
          automatic positioning of the source, the timer, and the
          automatic retraction if someone passed the warning gate and
          broke the photoelectric beam while the source was exposed. The
          failure did not affect the exposure device, control cable, or
          crank.
     2.   The alarm and warning light interlock system were completely
          functional except as described above. This was verified during
          the quarterly audit of this date.
     3.   The iridium 192 camera in the same exposure vault is operated
          manually.  The source does not automatically retract when the
          photoelectonic beam is broken.
     4.   The radiographers do not deviate from their normal

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          practices of maintaining surveillance or locking off the
          exposure area during exposures, always carrying an operable and
          calibrated survey meter into the exposure rooms, etc.

This is not a reportable event under 10 CFR; however, I am providing the
information to forstall any confusion at some later date.

Please contact me if you have any comments or desire additional
information.

Sincerely yours,

The Harrison Steel Casting Company
W.D. Hollander, RSO

cc:  R. Shepherd
     H. McBride

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