ANALISIS METALOGRAFI PELAT ELEMEN BAKAR U3Si2/Al DENSITAS 2,96 gU/cm3 PASCA IRADIASI

Abstract

Metallographic analysis of U₃Si₂/Al fuel element plate has been performed in hot cell. The purpose of metallographic analysis is to study changes in PEB U₃Si₂/Al microstructure and AlMg₂ cladding thickness after irradiation in reactor until burn up of 56%. The fuel element plate of irradiated U₃Si₂/Al was cut in top, middle and bottom positions with each size around 5x5x1,37mm. Metallographic preparation starts from sample cutting using cutting machine with low speed and sample mounting, grinding and polishing in hot cell 104–105. Sample mounting was done by using resin for more than 10 hours followed by grinding with sandpapers up to grit size of 2400 and polishing with diamond paste of size 3 to 1 micron at a rotational speed of 150 rpm for 5 minutes. Microstructure observation was performed with optical microscope in hot cell 107 at 200 times magnification. Microstructure examination reveals U3Si2 particles with diverse forms and sizes, Al matrix and AlMg₂ cladding were spread along the U₃Si₂/Al side. Microstructure observation of irradiated U₃Si₂/Al has not shown good result because only topography observation of U₃Si₂/Al meat, Al matrix and AlMg₂ cladding can be done due to limited capability of the optical microscope in hot cell, where maximum magnification can be attained only at 200 times so that the phenomenon of interaction layer and small gas bubble cannot be observed. However, U₃Si₂/Al microstructure of 56% burnup, if compared to the microstructure of U₃Si₂/Al fuel element plate of 60% burnup from previous researcher, shows interaction between U₃Si₂ meat with Al matrix and the existence of layers with a thickness about 5 up to 20 microns. Meanwhile, the observed thickness of AlMg₂ cladding is greater than 0.25 mm, which indicates that irradiation does not significantly change the thickness of AlMg₂ cladding so that the overall irradiated U₃Si₂-Al still has good integrity and stability.