Application of emergency reference levels of dose in emergency planning and response

The Board published formal advice on emergency reference levels (ERLs) of dose in 1990. This document provides more detailed guidance on how it is intended that the ERLs should be applied in the development of emergency plans. In particular, specific guidance is developed in the following areas: how to incorporate the concept of averted dose in emergency plans; the choice of dose quantities to be compared with the ERLs; the use of ERLs in the event of an actual accident. In order to develop the role and application of the ERLs, the different types of accident response criteria are discussed. In particular, a distinction is drawn between intervention levels (usually expressed as dose averted) and action levels (often directly measureable quantities), and also between generic and site specific accident response criteria. The ERLs are identified as generic intervention levels and, as such, their primary role is for use during the development of emergency plans. If an accident occurs, it is recommended that any urgent response should be triggered by the site specific action levels specified in the emergency plan. Subsequently, ERLs may be used to determine whether major modifications to this response are necessary. Only in the unlikely situation of the occurrence of a serious accident, for which there was no emergency plan which could be activated, should the ERLs be used as direct criteria, and then only for determining the most urgent response. (author)