SIGMA 150Ci - Manual (Page 69)

7.1
EMERGENCIES AND PERSONNEL SAFETY
Emergencies
During the termination of a radiographic exposure, observation of the survey meter
provides an indication of source movement while cranking the remote control handle.
After retracting the sealed source into the exposure device, radiographers are required to
perform a confirmatory survey of the exposure device, the projection sheaths and beam
limiter when used. Performing a confirmatory survey after a radiographic exposure is
required by regulation and is the only method that the radiographer should rely on to
determine if a source assembly is in the fully shielded position within the exposure device.
If the radiographer measures any radiation level that indicates the sealed source is not fully
shielded while performing the confirmatory survey, the radiographer must first recognize
that problem exists and then follow his company’s emergency procedures. Emergency
conditions are those problems in which the source assembly cannot be returned to the
shielded position by normal means, specifically the remote control crank mechanism.
The majority of problems experienced by radiographers are where the source assembly
becomes disconnected or when the source assembly becomes jammed in the projection
sheath while in an exposed position. The important safety points for radiographers to
follow are:
● Always perform a confirmatory survey after each exposure.
● If higher than expected radiation levels are measured, recognize that an
emergency exists. (Stop and Think!).
● Follow emergency procedures.
● Do not attempt to retrieve the sealed source. Secure the area and notify the
Radiation Safety Officer.
The radiography crew is limited to the following basic steps and must be adhered to
under regulation:
1 Immediately leave the area and maintain continuous surveillance of high radiation area.
2 Adjust the restricted area boundary to ensure the measured dose/rate is <2mR/hr.
Do not allow anyone into the area.
3 Immediately notify the Radiation Safety Officer.
4 Do not leave the area unattended under any circumstances. Maintain security of
the area until the Radiation Safety Officer arrives at the site.
Do not under any circumstances attempt to retrieve the source. Performing source retrieval
is a licensed activity that allows only specially trained RSOs to respond to an emergency.
This regulatory requirement is the result of overexposures to radiographers attempting to
handle emergency retrievals by themselves.
WARNING:
An unshielded source must not be picked up or handled at close range under any
circumstances. An unshielded source at close range can cause serious injury or death to
anyone who is exposed to it, even for a short duration of time.
Training
Formal classroom training in radiation safety, supervised hands-on training and certification
by an independent certifying organization of radiographers are essential components for
radiological safety in isotope radiography and is a regulatory requirement in the United
States and Canada.
Sentinel, AEA Technology QSA provides radiation safety and inspection & maintenance
training at the Baton Rouge, Louisiana and Burlington, Massachusetts facilities. On-site
training is available by arrangement.