Radiation Advisory Council radioactive substances activity threshold

Applications for user licence conditions that exceed the Radiation Advisory Council (RAC) threshold listed in the table below will be referred to the RAC for consideration. The table below uses the activity groups of radionuclides and prescribed activity found in Schedule 1 Prescribed activity of a radioactive substance of the Protection from Harmful Radiation Regulation 2013.

Activity Group	Licence condition(s)	Prescribed Activity MBq	RAC Threshold Unsealed GBq	RAC Threshold Sealed GBq
Group 1	S41	0.04	0.0002	0.0002
Group 1	S5, S23RO, S23NM, S23NMT	0.04	0.02	0.2
Group 1	S10, S12, S8	0.04	0.0002	0.2
Group 1	S19	0.04	N/A	20
Group 1	S7	0.04	N/A	40
Group 2	S41	0.4	0.02	0.02
Group 2	S5, S23RO, S23NM, S23NMT	0.4	2	20
Group 2	S10, S19, S12, S8	0.4	0.02	20
Group 2	S7	0.4	N/A	400
Group 3	S41	4	2	2
Group 3	S5, S23RO, S23NM, S23NMT	4	200	2000
Group 3	S7, S10, S19, S12, S8	4	2	2000
Group 4	S41	40	200	200
Group 4	S5, S23RO, S23NM, S23NMT	40	20000	200000
Group 4	S7, S10, S19, S12, S8	40	200	200000

Index of licence conditions

S5: Use radioactive substances for analytical purposes
S7: Use radioactive substances for industrial gauging
S8: Use radioactive substances for scientific or research purposes
S10:Use radioactive substances for installing and/or servicing devices containing a radioactive substance
S12: Use radioactive substances for calibration and quality assurance purposes
S19: Use sealed source devices (portable x-ray fluorescence (XRF) analysers) for analysis
S23RO: Use radioactive substances for veterinary radiation oncology - Veterinarians
S23NM: Use radioactive substances for diagnostic veterinary nuclear medicine - Veterinarians
S23NMT: Use radioactive substances for therapeutic veterinary nuclear medicine - Veterinarians
S41: Use radioactive substances for in-vitro medical diagnosis - Medical practitioners

Updated 20 March 2025