Metallography of irradiated materials in the hot cells

Metallography plays a vital role in the post irradiation examination of irradiated nuclear fuel and structural components. Because of the intense beta gamma radiation from the samples metallography of irradiated materials are carried out inside shielded cells. Transverse samples of fuel elements, longitudinal sections of end plug samples and irradiated pressure tube samples of PHWRs have been prepared using a remotely operable automated sample preparation machine. A remotised metallograph has been used for examination of the samples. This microscope is different in construction compared to the conventional microscope. Motorized movement, radiation resistant optics, shielding, quick grabbing and a powerful image analyzer are the features of the equipment. A micro hardness tester is coupled with the microscope for measuring the hardness. Remotised laser etching technique is being developed for ThO2. This technique will enable to etch ceramic fuel samples in the hot cells instead of the cumbersome, conventional etching techniques that are being used presently. β-γ autoradiography has been carried out on the metallographically prepared sample in the cell for understanding the fission product migration in the fuel. This paper will describe the details of remote metallography facility at PIED hot cells. The data generated on irradiated nuclear fuels and reactor structural components will also be discussed. (author)