This report documents the work undertaken in CONCERT sub-subtask 220.127.116.11 (Work Package 3, task 3.1 of the TERRITORIES project) that dealt with decision making processes related to the control of radiation safety in existing exposure situations; those that already exist when such decisions have to be made. Such situations can arise from a variety of circumstances and of particular concern are the aftermath of nuclear accidents and past practices that involved the processing of minerals with elevated levels of natural radionuclides that were not well controlled. Criteria need to be in place as a basis for decision making and assessment needs to be undertaken of what the level of exposure will occur over time and how effective control measures will be to reduce exposures. The establishment of criteria and the assessment of exposures and the effectiveness of control measures is complex, involve many assumptions and analytical processes. There are also has many associated uncertainties of scientific, economic, political and societal dimensions and these factors have led to considerable difficulty in managing existing exposure situations in the past. In order to be able to make good decisions in the face of these uncertainties, they need to be quantified and considered in the decision-making processes. This work is a first step to identify the main uncertainties of concern and to explore the difficulties that have arisen with their management in existing exposures that have arisen to date, with a view to developing improved mechanism for use in the future.
The work undertaken involved a review of European legislation relevant to existing exposure situations and the international recommendations and standards underpinning the legislation. It involved gathering information and developing insights into existing exposure situations that have arisen from major nuclear accidents and from the legacies arising from previous mining and minerals processing activities involving minerals with elevated levels of natural radioactivity, that were not effectively controlled. These two types of circumstances have some considerable difference in cause, scale and magnitude, but they also have many common dimensions related to the inherent uncertainties and the working group explored the transversal nature of these issues. The work has enabled a preliminary understanding to be developed of how uncertainty management comes into play in decision making processes for existing exposure situations and provides a framework for the future development of approaches and tools to be used in the future.