Information Notice No. 81-13: Jammed Source Rack in a Gamma Irradiator
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
April 14, 1981
INFORMATION NOTICE NO. 81 13: JAMMED SOURCE RACK IN A GAMMA IRRADIATOR
This information notice provides information about a general potential
problem area involving product pass systems and the source rack in certain
types of gamma irradiators used for research and product sterilization. This
information should be brought to the attention of all persons involved in
the administration and operational aspects of your irradiator facility.
Description of Event:
During manual shutdown of a gamma sterilizing irradiator, the source rack
failed to return to the shielded position in the storage pool. Subsequent
review of the event determined that the source rack was prevented from
returning to the shielded position by product carrier boxes that were
damaged and in disrepair. The product boxes had bent out corner edges and
flaps that extended into the travel path of the source rack. The source
remained in the unshielded position for approximately 24 hours.
Beginning about 10 hours after the jamming of the source rack and continuing
until it was returned to the shielded position, several fires occurred in
the product and product boxes. The fires were extinguished by the sprinkler
system. After approximately 24 hours, the source rack was successfully
lowered to the shielded position by a service crew from the manufacturer of
the irradiator. The jammed source rack defeated emergency shutdown systems.
Even though there was no damage to the source pencils, there was some damage
to the source pass conveyor that caused several days of down time.
This incident is significant relative to irradiator safety in that the
damaged product boxes prevented shutdown of the irradiator. Subsequent fires
also occurred in the combustible product and product boxes as a result of
prolonged gamma irradiation.
If your irradiator system uses a product pass system and/or product carrier
boxes, you should have procedures for inspection and removal of product
boxes that are damaged or in any other way could interfere with the source
No written response to this information notice is required. If you need
additional information regarding this subject, you should contact the
Director of the appropriate Regional Office.
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