Office for Nuclear Regulation

Revised detailed emergency planning zones principles

13 January, 2014

ONR revises the way it determines the area of detailed emergency planning zones (DEPZ) around nuclear licensed sites.

ONR has revised the principles that it will use to determine a nuclear site’s DEPZ – the area within which local authorities must prepare emergency plans in case of an off-site emergency.

From now on, in consultation with local authorities, ONR will base its decisions on consideration of practical and strategic factors, such as local demographic and geographical features that influence where the boundary of the DEPZ lies, as well as technical assessments. The purpose of this is to enhance preparedness, minimise response times, and, ultimately, improve protection of the public.

The revised principles will try to ensure that the boundary of the DEPZ does not bisect small communities, encompasses vulnerable groups that may have otherwise been located just outside the boundary, and considers the practical aspects for the local authority in planning and implementing their off-site emergency plans. This is likely to result in non-circular shaped DEPZs being adopted in future, even where the radiological hazard has not changed.

The revised principles show greater alignment with international standards and good practice which recommends that regulators consider additional factors and non-circular emergency planning zones. They principles also provide greater consistency, openness, and transparency to the public on how these zones are determined. 

The revised principles will be applied to sites on a rolling basis when their DEPZs are reassessed every three years under the Radiation (Emergency Preparedness and Public Information) Regulations 2001.

Further information about the principles for determination of DEPZs