What you need to know -the "graded approach".

From January 2018, all employers who undertake work with ionising radiations on nuclear premises* are required to either notify, register, or obtain consent via the ONR process in compliance with the Ionising Radiations Regulations 2017 .
Of the Ionising Radiation Regulations 2017, employers must comply with:
Regulation 5 - Notification of certain work,
Regulation 6 - Registration of certain practices, and/or
Regulation 7 - Consent to carry out specified practices.
The above three regulations together represent the UK's transposition of the 'Graded Approach' introduced in the EU Directive 2013/59/EURATOM .