The CHANCE project aims to address the specific issue of the characterization of conditioned radioactive waste (CRW). The characterization of fully or partly conditioned radioactive waste is a specific issue because unlike for raw waste, its characterization is more complex and needs specific non-destructive techniques and methodologies. There are different and varying reasons for this:
- conditioned waste may no longer be in its initial form (e.g., due to incineration);
- conditioned waste is typically embedded or surrounded by a matrix;
- conditioned waste may contain wastes coming from different primary sources and therefore the radiological spectrum might become more complex.
Characterization issues within CHANCE encompass both physico-chemical characterization and radiological characterization. The experimental focus within CHANCE is radioactive waste held in large volume compounds potentially containing hidden components, spent fuel held in large volume storage containers, problematic and legacy waste, specific waste arising from repair or maintenance, decommissioning/dismantling waste and radioactive waste destined for geological disposal.
The first objective of CHANCE is to establish at the European level a comprehensive understanding of current conditioned radioactive waste characterization and quality control schemes across the variety of different national radioactive waste management programmes, based on inputs from end-users such as Waste Management Organisations and storage operators. CHANCE will focus on the following waste forms (IAEA classification):
- Very Low Level Waste (VLLW (VLLW);
- Low Level Waste (LLW);
- Intermediate Level Waste (ILW);
- High Level Waste (HLW).
Very Short Level Waste and Exempt Waste are beyond the scope of CHANCE as these kinds of waste are not destined for a specific radioactive waste disposal. The establishment of a "waste characterization catalogue" will allow current short-comings of state-of-the-art characterization of conditioned radioactive waste to be identified.
The second objective of CHANCE is to further develop, test and validate techniques already identified that will undoubtedly improve the characterization of conditioned radioactive waste, namely those that cannot easily be dealt with using conventional methods.
Input from “end users” (mainly waste management organizations and waste producers) on methods of conditioned radioactive waste characterization is critical to the success of CHANCE. Therefore, a dedicated End-Users Group will be established within CHANCE in order to represent and promote the interests and requirements of end-users. One of the project’s key tasks will be dedicated to the identification of links and overlaps between waste acceptance criteria and actual waste characterization technologies available, in order to identify specific, as yet unsolved, methodology issues and technology gaps.
CHANCE’s R&D programme consists of the testing and evaluation of the performance of 3 innovative characterization techniques that are complementary and supplementary to current techniques for the non-destructive assay of RW, specifically:
- Calorimetry as an innovative non-destructive technique to reduce uncertainties on the inventory of radionuclides (RN), namely from hidden RN-compounds with a weak gamma signal.
- Muon Tomography to address the specific issue of the non-destructive interrogation of the content of large volume RW.
- Cavity Ring-Down Spectroscopy as an innovative technique to characterize outgassing of RW at a very low detection level.