[en] At the time of a licence application of effluent releases and water pumping of basic nuclear facilities (BNF), the operator of the installation must in particular provide a radiological impact study of the radioactive effluent releases coming from the installation on the environment and on public health. An impact study of the radioactive releases represents technical and conditional specifications. It was for this reason that the French Safety Authority (ASN then DSIN) and the Directorate-General of Health Services (DGS) requested IRSN (then IPSN), in April 1999, to develop a guide facilitating the review of such a study, as well for the services implied in the examination of the licence applications, as for all the concerned parties in this field. The objective of the guide is to take into account the regulatory context which underlies the development of the impact studies (decree no. 95-540 of May 4, 1995, modified by the decree no. 2002-460 of April 4, 2002, and the Euratom guideline 96/29 of May 13, 1996, known as 'the basic standard guideline', accompanied by its transposition texts in French law). In this precise context, the guide proposes to assess the radiological impact study of a BNF from three different angles: - the description and the quantification of the produced effluents, by taking account of the triggering processes, of the different processing measures and of the procedures to optimise the reduction of the produced effluents; - the estimate of the dosimetric impact of the planned releases on the population, taking into account the environmental characteristics of the installation; - the definition of the conditions to monitor the releases and the environment. This guide provides a general condition logical framework adaptable to any particular situation met