United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 75-02: Defective Radionics Radiographic Exposure Devices and Source Changers



BL75002 

                                        Office of Inspection and Enforcement
                                        IE Bulletin No. 75-02 
                                        Date. February 14, 1975 

DEFECTIVE RADIONICS RADIOGRAPHIC EXPOSURE 
DEVICES AND SOURCE CHANGERS 

Description of Circumstances: 

A recent shipping incident investigated by the State of Louisiana's Division
of Radiation Control has revealed that some RADIONICS INCORPORATED 
radiographic devices may be defective in construction, permitting excessive 
radiation levels (particularly in the area of the base) even when the source
is locked in the "safe" position. More than one type of potential defect has
been noted. They include source tubes of improper length, discrepancy as in 
the number of shims installed between the camera and lockbox, and excessive 
movement of the pigtail in the locked position. These defects are not 
limited to any particular model. Therefore, all RADIONICS devices are 
considered suspect pending completion of a careful radiation survey. NRC 
(formerly AEC) regulations (10 CFR 34.21) impose limits on radiation levels 
for radiographic exposure devices and storage containers. 

Actions by licensees are necessary in locating and removing from service any
RADIONICS devices that are defective. 

Actions to be Taken By Licensees: 

All licensees currently authorized to possess RADIONICS devices are 
requested to take the following actions: 

1.   Complete the upper portion of the enclosed "Survey Report Form" with 
     regard to the number of RADIONICS devices you have in your possession. 
     If none, you need only so state and return the form to this office. 

2.   For each RADIONICS exposure device or source changer in your 
     possession, perform a careful radiation survey as described in 
     Enclosure No. 1 to this Bulletin entitled "Survey Procedure." It is 
     possible that any excessive radiation levels will be in the form of a 
     narrow, collimated beam so it is important that the survey meter be 
     moved slowly to permit it to respond to any "hot spots." 
     
3.   Record the survey results on the enclosed form separately for each 
     device. Determine the "converted readings" as described in Step 3 of 
     the survey procedure and record this value on the survey report form. 

4.   Remove from service and place in secure storage any devices with 
     measured or converted radiation levels in excess of 50 milliroentgens 
     per hour at six inches.  
.

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5.   Return the completed forms within 30 days of your receipt of this 
     Bulletin to: "USNRC, Office of Inspection and Enforcement, Attention: 
     Radiological and Environmental Protection Branch, Washington, D.C., 
     20555. 

Enclosures: 
1. Survey Procedure  
2. Survey Report Form  
2-A. Survey Report  
     Continuation Sheet 
.

                            SURVEY PROCEDURE 

     MAKE CERTAIN THAT PIGTAIL ASSEMBLY IS SAFELY LOCKED IN POSITION: 

1.   While the device rests on its base, using a calibrated, operable survey
     meter, carefully and slowly perform a survey at: (1) all accessible 
     surfaces (other than base) and, (2) at a distance of six (6) inches 
     from the detector to the surface. Look for "hot" spots. Record the 
     maximum reading obtained. You may find it easier to survey directly on 
     the surface to find such hot spots, then measure the value at 6 inches. 
     Perform the above surveys while moving pigtail back and forth but do 
     not unlock. 
     
2.   Turn the device on one side and carefully survey: (1) the bottom 
     surface of the device and, (2) at a distance of six (6) inches. Move 
     the survey meter slowly to allow it to respond to small "hot" spots. 
     Move pigtail back and forth, but do not unlock. Record the maximum 
     reading obtained. 
     
3.   Convert the measured maximum readings at 6" to those which would result
     if the device were loaded to its rated capacity (allow an excess of 20%
     for Ir-192, and 10% for Co-60). Multiply your reading in mR/hr by the 
     camera capacity, plus 20% or 10% whichever is appropriate, then divide 
     that product by the activity in Curies actually in the device (consult 
     decay chart). For example: 

          Suppose the camera is a P192-100 loaded with 25 Ci and one reading
          is 15 mR/hr @6". Allowing 20% excess for Iridium-192 , the 
          capacity would be 120 Ci. 

               Then: 15 mR/hr x 120 Ci/25 Ci = 72 mR/hr 

Note: 

Any direct or converted reading which is greater than 50 mR/hr at 6" 
indicates a defective device. (The example given would be a defective 
camera.) Such devices should no longer be used. 

                              ENCLOSURE NO. 1 
Page Last Reviewed/Updated Tuesday, July 23, 2013