Radionuclide mobility under perturbed conditions (RAMPEC)
Objectives
Improve the predictive capacity of models of disposal system chemistry and radionuclide mobility under perturbed conditions based on a combination of new experimental and modelling studies up to the cell scale.
Description of the WP
Good understanding of radionuclide (RN) behaviour in argillaceous, crystalline and cementitious systems under equilibrium conditions has been derived from past experimental studies in simplified reference systems. Radionuclide and gas behaviour under perturbed conditions, however, are poorly constrained and up to date there is no integral model based description for perturbed systems. In addition, the capability of describing the chemical evolution of in-situ conditions in such systems has not yet reached a necessary level of maturity to deliver deterministic predictive reactive transport modelling of the nearfield.
RAMPEC will provide improved methods and approaches both regarding mechanistic modelling of radionuclide retention and migration on the disposal cell scale (meter to decametre scale). This will be achieved by the use of existing data from previous projects (FUTURE, CORI, …) and targeted new experimental investigations. All R&D Tasks aim for both scientific excellence and high relevance in the applied context. The restriction of RAMPEC on three systems (Clay, Granite, Cement) with a limited number of specific perturbations relevant to each system to be investigated, ensures a meaningful WP with a clear focus. It likewise ensures inclusiveness and opens new opportunities for coherent and forceful collaborations between the Tasks and Subtasks described below. RAMPEC will thus allow for a broad international cooperation throughout Europe with excellent opportunities for education and training as well as sharing of resources and expertise.
Outcomes
The proposed R&D Tasks address the effects of chemical and physical perturbations on radionuclide behaviour in selected systems, and elaborate a mechanistic description of these processes to provide input for Performance Assessment (PA). The work in RAMPEC thus requires a close interaction between experimentalists and different modelling experts. The implementation of specific networking and collaborative research efforts (spanning from atomistic information via lab-scale experiments to modelling at disposal cell scale (meter to decametre scale) with input to PA) is an important outcome in RAMPEC. (=> KM).
RAMPEC prioritises the involvement of PhDs and young researcher in both the experimental Task 3 and the modelling Tasks 4 and 5. The required specific networking between the Tasks opens excellent training and education opportunities and enhances a “generalist” view on Radioactive Waste Disposal research beyond individual technical specializations. (=> KM).
Technical outcome includes:
Targeted new experimental studies on radionuclide retention and transport (sorption, diffusion) under perturbed conditions. Studies comprise necessary experimental work to allow process understanding in complex systems. Work is not limited to ternary systems, but also provides a proper understanding and description of underlying binary systems. (=> Implementation Safety, Scientific Insight).
Development of mechanistic models for retention and transport of radionuclides in complex physico-chemical systems, based on an accurate and realistic description of natural systems and chemical speciation (Task 4). This is including model based descriptions for in-situ conditions in the repository near field under external perturbations. (=> Implementation Safety, Scientific Insight).
Development of a “sorption database” focusing on the specific systems to be investigated in RAMPEC. This will support modelling activities and serve as a proof-of-concept for potential related database projects beyond the scope of RAMPEC (Task 2). (=> KM).
Upscaling and data transfer from small scale laboratory experiments to the disposal cell scale (meter to decametre scale) in view of PA requirements (Task 5). Including choice of « macroscopic » parameters and benchmarking. (=> Implementation Safety).
