United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9512180157

P. O. Box 5247             Omnitron

3409 West Prien Lake Road   International, Inc. Telephone: (318) 474-0505

Lake Charles, Louisiana 70606                         Fax: (318) 478-6218

December 6, 1995

Document Control Desk

U. S. Nuclear Regulatory Commission

Washington, DC 20555

Re:  Part 21 - Reporting of Defects and Noncompliance

     Omnitron Report # 0101 Addendum

Subject:  Incident at Indiana Regional Cancer Center, November 1992

          NRC Report NUREG-1480

Dear Madam or Sir:

Pursuant to 10 CFR 21 and a request from Mr. Larry W. Camper, Office of

Nuclear Materials Safety and Safeguards, Omnitron International Inc.,

reports the following additional information to be added to the report

dated March 16, 1993:


     Model 2000 HDR Treatment System, Afterloader S/N 100, Source Wire,

     Model SL 777.

     Additional Information

     In response to NRC comments the Afterloader software has been

     changed as follows:

     After any emergency DC motor retraction, the Afterloader is

     inoperable until serviced, an alarm is sounded, and below error

     message is displayed in a red box on the console monitor screen

     until cleared by medical personnel:

          CHECK RAD MONITOR, Backup retract motor activated

          POSSIBLE EMERGENCY!, verify source in safe


     During an emergency DC motor retraction the length of the wire is

     not recorded as all components that could in any way restrict the

     movement of the wire are retracted from making contact with the

     wire.  This retraction includes the encoders that measure the wire

     length.  This is as designed to ensure that the DC motor will always

     be capable of pulling the active wire back.

Letter to U. S. NRC, 12/06/1995

Page 2

The above change was implemented in September of 1993 and all licensed

users were notified of the change.  This change was not implemented as a

result of any failure of the system but was done to further assist

medical personnel to understand what should be done when the Backup

Retract Motor activates.

Omnitron will be responsive to any comments or suggestions the NRC may

have regarding this report.


Sam Lott, Ph.D.




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