5. High Activity Sealed Sources (HASS)

HASS - High Activity Sealed Source

HASS means High Activity Sealed Source. HASS in the UK came into force as the: ‘High-activity Sealed Radioactive Sources and Orphan Sources Regulations 2005’. These regulations only applied to very high activity sources (e.g. for Cs-137 the activity needs to exceed 100 GBq) – typically those found in irradiators and radiography equipment. Users of such sources need to apply much more stringent security procedures and prove that they have the funds to dispose of such sources at the end of their useful life.

[Note: Originally the HASS threshold for Cs-137 was 20 GBq. This, and other radionuclide HASS thresholds were at the time based on IAEA A1 transport values. This was amended by BSSD Council Directive 2013/59/EURATOM and since then the HASS thresholds have been based on the IAEA-D values, these are discussed in more detail in this section of the resource: 6. Sealed source category and the 'D' value. You may also wish and visit the IAEA document which is here: Dangerous Quantities of Radioactive Material (D-Values) (will open in a new tab). ]

HASS is now taken care of by The Environmental Permitting (England and Wales) Regulations 2016 in England and Wales (which covers the same conditions from within Schedule 23). In Scotland, the Environmental Authorisations (Scotland) Regulations 2018 deal with HASS, and in Northern Ireland the Radioactive Substances Act (1993) deals with radioactive substances but the High-activity Sealed Radioactive Sources and Orphan Sources Regulations 2005 are still in force.