United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 85-36: Malfunction of a Dry-storage, Panoramic, Gamma Exposure Irradiator

                                                       SSINS No.:  6835  
                                                         IN 85-36          

                               UNITED STATES 
                           WASHINGTON, D.C. 20555 

                                May 9, 1985 

Information Notice No. 85-36:   MALFUNCTION OF A DRY-STORAGE, PANORAMIC, 
                                   GAMMA EXPOSURE IRRADIATOR 


All licensees possessing gamma irradiators. 


This information notice is provided to alert recipients of a repeat instance
of failure of a gamma exposure irradiator despite notification of a defect 
by the manufacturer. 

It is expected that licensees will review this notice for applicability to 
their facilities, if appropriate, to preclude a similar problem from 
occurring at their facilities.  However, suggestions contained in this 
information notice do not constitute the NRC requirements; therefore, no 
specific action or written response is required. 

Description of Circumstances: 

In 1981, a dry-storage, panoramic, gamma exposure irradiator had a problem 
with a source that failed to return to its safe storage position. It was 
discovered that springs used as source spacers and energy absorbers for 
positioning and impact control had broken. The broken chips interfered with 
free movement of the source by reducing or eliminating the clearance between
the source capsule and its exposure tube.  

The irradiator manufacturer, Atomic Energy of Canada Limited, (AECL), sent a 
warning notice to the persons who possessed identical irradiators informing 
them of the potential problem. The notice advised that they should stop use 
of their irradiator and return it to AECL for new springs. 

A nuclear research center in a foreign country possessed one of these 
irradiators but failed to respond to the manufacturer's notice and continued
operation of the irradiator. In February 1985, an event similar to that 
described above occurred with the result that a 700 curie cobalt-60 source 
became stuck in its tube.  Because the irradiator is inside of a shielded 
facility, it appears that no one received an excessive exposure to 
radiation; however, the facility is inoperable. 


                                                              IN 85-36     
                                                              May 9, 1985  
                                                              Page 2 of 2  

Licensees can avoid serious problems by paying prompt attention to notices 
from equipment vendors dealing with problems and following instructions for 
proper use and maintenance of equipment. 

No specific action or written response is required by this information 
notice. If you have any questions about this matter, please contact the 
Certification and Procedures Branch, Office of Nuclear Materials Safety and 
Safeguards (NMSS), or the Safeguards and Materials Programs Branch, Office 
of Inspection and Enforcement (IE) at NRC headquarters. 

                                   James G. Partlow, Director 
                                   Division of Inspection Programs 
                                   Office of Inspection and Enforcement 

Technical Contacts: N. Bassin, NMSS 
                    (301) 427-9027  

                    J. Metzger, IE  
                    (301) 492-4947  

Attachment:    List of Recently Issued IE Information Notices
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