Preliminary Investigations into the Compatibility of Ceramics with HTR Helium in the Dragon Reactor (ACE 2)

Strong thermal stress resistant ceramics are now being considered for use in high temperature nuclear engineering. Successful utilisation of ceramic materials in this area is dependent upon the provision of reliable information on thermophysical properties such as thermal conductivity, thermal diffusivity, thermal expansion, stiffness and Poisson's ratio, material strength and corrosion/oxidation resistance in the HTR-helium environment. Information on variation in these properties with temperature is also necessary for precise stress computations to be carried out on complex shaped components. In this experiment, the compatibility of selected ceramics - in the form of small collars - with the HTR helium environment will be studied. The nature and the extent of the reactions that take place under realistic reactor operating conditions and the possible failure mechanisms that might be enhanced by such reactions will be studied. This is the second experiment within the active materials programme which deals exclusively with ceramics. The first experiment was reported as part of D.P. Report 914. (author)