Radioactive Sources and Equipment
What this domain tests
This domain covers sealed source construction, classification, source projectors, collimators, source changers and security. The exam expects you to match equipment to the job and to recognize when a source or accessory is unfit for service.
Core rules
- Sealed sources are classified under ISO 2919 by performance for temperature, pressure, impact and vibration. A higher class is not automatically required; the class must suit the working conditions.
- The source capsule, not the projector, is the primary containment. The projector provides shielding, source movement and locking; its condition affects safety but does not change the source classification.
- Collimators reduce the beam angle and scatter; they must be fitted correctly and checked before exposure.
- High-activity sealed sources require enhanced security: inventory, locked storage, access control and immediate reporting of loss or theft. The IAEA Code of Conduct is a benchmark, not a substitute for national law.
- Leak testing is periodic and records must show date, method, result and action. A leaking source is removed from service.
Worked example
A field team proposes to use a projector whose locking mechanism is stiff and whose source guide tube has a flattened end. Reasoning: the locking defect and deformed guide tube can cause the source to stick or fail to retract. The equipment is removed from service; the source is not worked around. The correct action is to tag out, notify the RPO, and use a compliant replacement.
Traps
Assuming a higher ISO class source can be handled less carefully; using a collimator as a substitute for barriers; skipping leak tests because the source is new; treating the projector as the containment boundary.