Practical needs in the development of risk analysis methodology for the final stage of facilities’ life cycle

The paper discusses radiological, radioecological and technical characteristics of facilities and processes that are important in terms of risk analysis performed for the final stages of nuclear and radiation hazardous facilities’ life cycle. The paper presents an elaborated model used to rank facilities according to relevant potential hazard levels at the pre-decommissioning stage and during their decommissioning. The model has been developed on the basis of relevant NDA (UK Nuclear Decommissioning Authority) methodology specifically tailored for Russian realities. This approach considers both the state of engineering structures and the characteristics of radioactive substances and materials held inside the facility. Its efficiency has been demonstrated on a great number of facilities. The impact of uncertainties associated with initial data has been evaluated. A methodical approach to perform comparative analysis of risks and costs associated with defining radioactive waste as special or removable has been developed, thus, enabling to perform the initial registration of radioactive waste and relevant sites under the basic provisions of the federal law №190-FZ «On the Management of Radioactive Waste and Amendments to Certain Legislative Acts of the Russian Federation» of July 11, 2011. Radiological, radioecological and financial criterial indicators established in the Resolution of the Governement of the Russian Federation № 1069 of October 19, 2012 have been fully considered in this approach. It is proposed that the concept application of generalized collective risk of potential exposure should be extended to the time period covering all management activities involving accumulated radioactive waste.