You will need this licence if you intend to deal with radioactive materials or sources.
A radiation source is a thing that emits or may emit radiation. It can be radioactive material or a radioactive apparatus. Radioactive material is material that spontaneously emits ionising radiation as a consequence of nuclear transformations. A radiation apparatus is an apparatus that produces radiation when energised, or is, if assembled or repaired, capable of producing radiation when energised.
For example, radioactive sources are used by importers / exporters, hospitals, medical practitioners, pharmacists, research institutions, manufacturers, geological surveyors, universities and oil rigs.