Office for Nuclear Regulation publishes revised principles for determining safety zones around nuclear sites

Details of arrangements for establishing public protection zones around nuclear sites have been published by the government's nuclear safety watchdog following pressure from non-government organisations concerned about risks posed by a nuclear emergency.

Determining the area around nuclear sites where special countermeasures will be required to protect members of the public in the event of an off-site nuclear emergency is one of the most important and controversial roles of the Office for Nuclear Regulation (ONR).

The ONR has been reviewing its procedures for this determination for almost two years and has now published a set of revised principles upon which the determination process is based.

Under the published arrangements ONR relies on the operator of a nuclear site to provide an assessment of the 'worst forseeable accident' at the site and map the area within which members of the public could receive an unacceptable dose of radiation.  ONR then reviews this information in consultation with local authorities before setting a 'detailed emergency planning zone' (DEPZ) around the site, within which members of the public would be advised to take countermeasures such as sheltering inside a building to protect themselves from radiation.

According to the newly published ONR guidelines, two principles should be considered when setting the size of the DEPZ:

  • “A technical assessment of the area likely to be affected by a radiation emergency as defined in the Radiation (Emergency Preparedness and Public Information) Regulations 2001  (REPPIR)";
  • "An assessment of the practical and strategic implications of implementing countermeasures and aid those members of the public who are likely to be affected by a radiation emergency. This assessment involves the consultation with local authorities and includes local demographic and geographical considerations.”

The principles mean that ONR will look beyond a technical assessment of the hazards on site and also consider local practical and geographical issues in the operation of the off-site nuclear emergency plan.

Pete Wilkinson, Director of Nuclear Information Service, said of the revised principles, "Beyond the decision to look more closely at the practical implementability of the DEPZ, it appears that nothing has changed.  The ONR’s assessment is still based on information from the operator which is likely to take an optimistic view of the effects of an accident, the initiating incident does not take into account unforeseeable accidents or major terrorist incidents, and the size of the DEPZ is still based on a level of exposure to radiation for which it is impossible to predict the health effects on people who are exposed."

Non-government organisations concerned about nuclear safety have repeatedly raised concerns about a lack of transparency in procedures for establishing emergency protection zones with ONR over recent months.  A report commissioned by Nuclear Information Service from consulting engineers Large & Associates in 2012 highlighted a series of shortfalls in arrangements for calculating emergency protection zones at Atomic Weapons Establishment sites.



Declaration of interest:  Pete Wilkinson, Director of Nuclear Information Service, is Chair of the Office for Nuclear Regulation NGO Forum.

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