Radiation Protection Glossary

A radiation protection glossary for Radiation Protection Supervisors (RPS), Radiation Protection Advisers (RPA) and anyone else interesting in radiation safety terms and definitions. The glossary is a mixture of health physics , phrases related to radiation protection legislation, transport, practical safety, technical terms and similar.

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For formal advice, see our Radiation Protection Adviser pages. 


Justification is one of the first three principles of the ICRP system of radiological protection. Justification, together with Optimisation and Limitation, are used as the basis of Radiation Protection internationally. Justification is defined in the ICRP 123 publication as 'no practice involving exposures to radiation should be adopted unless it produces sufficient benefit to the exposed individual or to society to offset the Detriment it causes'.

In radiation protection I spend most of my time explaining to clients what they do not need to worry about.

– Mark Ramsay -