A study has been done on the optimisation of concrete structures for near surface disposal of low and intermediate level radioactive waste. The aim of the experimental work was to analyse the behaviour of cracked reinforced concrete, with different levels of fissuration and different components, subjected to accelerated ageing tests. With the selected cement and aggregates and cracks of less than 0.4 mm in size the tests showed no significant change in the mechanical properties of the concrete or the corrosion potential of rebars.
The objective of the modelling work was to analyse the tensile stress in the most vulnerable sections of the structure which could serve to index the fissuration of the concrete section. Tensile stress due to thermal gradients cannot be avoided and reinforcement must be calculated to minimise the crack size. A size of 0.1 mm has been adopted as a limit.