Dounreay’s detailed emergency planning zone is being reduced from 5km to 1.15km.
The change reflects the lowering of the radiological hazard at Dounreay through progressive decommissioning.
The zone is the area around the site where public protection measures are planned in detail. The boundary reflects the worst-case radiation emergency that can be reasonably foreseen, resulting in potential exposure of people to five millisieverts or more of radiation. (The average annual exposure to a member of the public from all sources of radiation is 2.2 millisieverts.)
Previous assessments found these conditions could occur up to 5km from the site but the latest assessment revised this to 1.15km.
The number of households within the old 5km zone was over 200, whereas the number of households within the new zone is five.
“We have a duty to reassess the hazard at the site on a regular basis under the Radiation Emergency Preparedness and Public Information Regulations (REPPIR) and ensure our emergency arrangements reflect the reality of the situation," explained Colin Macdonald, emergency planning manager at Dounreay.
The justification for a smaller planning zone has been accepted by the Nuclear Installations Inspectorate of the Health and Safety Executive, which has formally notified Highland Council as the body responsible for all emergency planning in the region.
“We’re working with the council to amend the on-site and off-site plans to ensure we will continue to have seamless arrangements in place,” added Colin Macdonald.
The emergency planning zone around the neighbouring Vulcan site is unaffected.