The CHANCE project addresses specific issue of the characterization of conditioned radioactive waste. Unlike for raw waste, the characterization of fully or partly conditioned radioactive waste is a specific issue because its characterization is more complex and emphasises specific non-destructive techniques and methodologies. There are various reasons: 1) conditioned waste may no longer be in its initial form, 2) conditioned waste is typically embedded or surrounded by matrix material, 3) conditioned waste may contain wastes from different primary sources and therefore a more complex radiological spectrum is expected. Characterization issues within CHANCE encompass both physico-chemical characterization and radiological characterization.
The experimental focus of CHANCE is radioactive waste held in large volume compounds potentially containing hidden components, e.g. spent fuel in large volume storage containers, problematic and historical waste, specific waste arising from repair or maintenance, decommissioning/dismantling waste. CHANCE concentrates on radioactive waste destined for geological disposal.
The objectives are:
- 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 with a focus on Very Low Level Waste; Low Level Waste; Intermediate Level Waste ; High Level Waste. Very Short Level Waste and Exempt Waste are beyond the scope of CHANCE as these kinds of waste are not destined for geological disposal.
- 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.
The proposed R&D programme consists of assembling the appropriate hardware and tools for testing and the evaluation of the performance of 3 innovative characterization techniques that are complementary and supplementary to current techniques for the non-destructive assay of radioactive waste. Outstanding and specific issues concerning the characterization of conditioned radioactive waste, in particular where current methods fall short or are too imprecise or incomprehensive, will be addressed.
Destructive technologies followed by chemical or radiological analyses are commonly used techniques for radioactive waste characterization. However, they are not addressed here. Since these techniques are routinely applied to the raw waste itself, this is not in the scope of CHANCE project.
Specifically, the work focusses on:
• Calorimetry as an innovative non-destructive technique to reduce uncertainties on the inventory of radionuclides;
• Muon Tomography to address the specific issue of non-destructive control of the content of large volume nuclear waste;
• Cavity Ring-Down Spectroscopy (CRDS) as an innovative technique to characterize outgassing of radioactive waste.
