A Holistic Process for Decision Making on Decommissioning and Management of Complex Nuclear Sites

The Nuclear Energy Agency (NEA) Expert Group on a Holistic Process for Decision Making on Decommissioning and Management of Complex Sites (HDCS) was created on 25 June 2020 by the NEA through its Committee on Decommissioning of Nuclear Installations and Legacy Management (CDLM). HDCS serves as a forum for international exchange and co-operation on decision making for complex sites with different levels of uncertainties. In agreement with the mandate of the HDCS, the objective of this expert group is to develop a holistic process for decision-making considering both decommissioning and legacy aspects, and to provide guidelines to allow an integral progression from recognition to resolution to decommission and manage complex sites.

The HDCS expert group started on the basis of the work performed from 2016 to 2019 by the Expert Group on Legacy Management (EGLM) established by the NEA, through its Committee on Radiological Protection and Public Health (CRPPH). The specific goal of the EGLM was to develop a practical and harmonised approach to the regulation of nuclear and radiological legacy sites and installations. The results of the EGLM were published in 2020 in the report Challenges in Nuclear and Radiological Legacy Site Management - Towards a Common Regulatory Framework (NEA, 2020). This report was supported by the development of 13 case studies considering a large set of situations and countries, and site visits to Sellafield in the United Kingdom and to the Andreeva Bay site for temporary storage of spent nuclear fuel on the Kola Peninsula, Russia.

During the four-year period of the mandate of the HDCS expert group, a progressive work methodology was developed to address the possible steps of a holistic approach, sharing results within other NEA committees and forums but also in the framework of international events. To support the development of a holistic process, further insights have been gained from additional case studies provided by Canada, France, the United Kingdom and the United States to address both decommissioning and legacy aspects. These test cases cover different kinds of situations and sites with significant experience.

The expert group prepared the present report, with the support of the NEA Secretariat, describing the results obtained, presenting the supported case studies collected, and integrating the external feedback received during dissemination events. The principal outcome is the description of the main steps of a holistic process, as shown below (Figure ES1) and addressed in the body of this report.