The PRACLAY Heater test after two years of the stationary phase

This report summarises the observations realised in the PRACLAY Heater experiment after 2.5 years of heating the clay at 80°C at the Boom Clay/ concrete lining interface. The report directly follows the Start-up phase report published in May 2016 (EUR_PH_16_025). These observations lead to the general conclusion that the Heater test is a success. The experimental set-up has been found to be reliable and the whole system has generally evolved as expected. It has been proved that the clay is able to sustain the thermal load that would be generated by high-level, heat-emitting radioactive waste. Furthermore, our understanding and knowledge of clay behaviour will enable us to predict adequately the evolution of the temperature and the pore water pressure surrounding real disposal galleries in poorly indurated clay.