[ RadSafe ] Radiography

[William Lipton]

Here's an example of how to handle a radiography event:

*The following report was received from the Kansas Bureau of Environmental
Health via facsimile:

"During radiography operations on the night of 5 Aug 2013, two employees, a
radiographer and an assistant radiographer of Coder Welding & X-ray Service
were finishing an 8 hour shift (which is 2nd shift for Alstom), when the
source and crank assembly would not operate correctly. At that time, they
could only determine that the source had not fully retracted into the
camera correctly. After several additional attempts, they concluded a
malfunction of unknown causes prevented the source from retracting to a
full and locked condition. Following Coder Operating and Emergency
protocol, the first action was to secure and maintain a 2mr/hr boundary. A
complete survey of the area determined that the original roped and
placarded boundaries were still correct and valid. Next the RSO was
contacted as well as the assistant RSO. The RSO advised the radiographer to
secure and maintain the 2mr/hr boundary and asked if any personnel or
workers had been exposed to radiation levels in excess of those in Kansas
Radiation Protection Regulations, Part 4 and following, and they stated no.
They were advised that the RSO would be on site in 90 minutes to oversee
the incident and resolve the situation. While waiting for the RSO to
arrive, the two Coder employees decided to extend the roped boundaries an
additional 75 feet in addition to the existing roped area and inform Alstom
management of the situation. Since this was the end of 2nd shift for Alstom
workers, and no Alstom workers were in the area at the time, there was no
disruption of production or evacuation needed. Any Alstom employees on site
were advised not to enter plant area as a precaution. At no time were Coder
or Alstom employees at risk or in danger of overexposure.

"The RSO arrived on site at approximately 12:15 p.m. and made a radiation
survey of the area and boundaries. The RSO found correct actions had been
taken and 2mr/hr boundaries were maintained. In fact, 1mr/hr was the
highest reading. The RSO then walked up to the crank-out reel and found the
radiation level to be 5mr/hr. He concluded that the source was in fact in
the tungsten collimator (4.3 hvl [half value integers]) secured on the pipe
weld where it was during earlier radiographic operations. Several attempts
to return the source to its shielded and locked condition failed, so plans
were made to allow for closer inspection of the cables and source tube. At
this point, the assistant RSO was contacted and advised to bring additional
drive cables and source tube in the event they could be needed. While the
radiographer and assistant radiographer maintained security over the
boundaries and source, the RSO and several Alstom management, who had
arrived on site, went outside to look for suitable shielding that could be
brought in. Two one inch plates were chosen for use. The plates were tack
welded together and moved to an area where overhead cranes could be used to
move into position. This was accomplished by using the remote controls of
the crane system so no person would have to be in a high radiation
environment. With help from Alstom personnel, the steel plates were
directed into place by the RSO next to the source camera, providing
additional shielding. It was then possible for the RSO to walk up to the
source camera with a survey level of 32mr/hr. It was then possible to
inspect the drive cables and look at the source tube for possible causes of
the return failure. A small depression was noted some 6 to 7 feet from the
camera and cable attachment. Using a hacksaw, pliers, and other tools, the
outer cable shielding was removed and the RSO returned to the cable crank,
and was able to retract the source into the camera in the full and locked
position. During the entire operation the RSO received a whole body dose of
35 mr.

"Due to the time and distance for the RSO, late arrival of the assistant
RSO arrival on site, and the caution taken to resolve the situation, some
3-1/2 hours elapsed from the start to the end. The help and materials
provided by Alstom management aided in the safe and satisfactory conclusion
of this incident. At this time, it is unknown what might have caused the
depression in drive cables or why it suddenly caused a failure to retract
situation."

Kansas Report Number: KS130006*