PEMBUATAN SERBUK U-6Zr DENGAN PENGKAYAAN URANIUM 19,75 % UNTUK BAHAN BAKAR REAKTOR RISET

MAKING OF U-6Zr ALLOY POWDER WITH URANIUM ENRICHMENT OF 19.75 % FOR RESEARCH REACTOR FUEL. Making U-6Zr alloy powder with enrichment of 19.75 % for a research reactor fuel has been done. Making of U-6Zr fuel in order to find new fuels that have a high density to replace the existing fuel U3Si2-Al. The purpose of this experiment was to determine the properties of U-6Zr alloy powder obtained from the hydriding-dehydriding process as a candidate research reactor fuel. Initially was made U-6Zr ingot by melting U and Zr metals using electric arc melting furnace. U-6Zr ingots were found then cut into pieces and put into hydriding- dehydriding equipment that operates at pressures 14,46054 psi and hydriding temperatures of 350 oC. Ingots that out of the hydriding-dehydriding equipment becomes brittle then was crushed so becomes powder. Powder that obtained subjected to the test, including chemical composition testing, density, hydrogen content, phase and thermal properties. The results testing show that chemical composition of some elements such as Al, Ca, Cu, and Ni exceeded the permitted limit, each of which contained elements of 202.21 ppm, 214.05 ppm, 61.25 ppm, and 134.53 ppm. On testing the density obtained that U-6Zr powder density of 13.57 g/cc and the testing of hydrogen residual content obtained hydrogen residual content of 0.16 %. For the testing phase were obtained the αU and δU phases, while in testing of the transformation temperature, there are two peaks, the first peak occurs at a temperature of 274 to 311 °C and a second peak occurs at a temperature of 493 to 527 oC. The first peak occurs endothermic reaction by absorbing heat of 6.23 cal/g but not formed a new phase, while the second peak occurs exotermic reaction with brought out heat of -9.34 cal/g and formed αZr phase. Meanwhile, the heat capacity of the test at temperature of 34 to 75 °C, the decrease in the value of the heat capacity accompanied heat absorption. At higher temperatures up to 437 °C, heat capacity value becomes negative and accompanied by heat expenditure. It can be concluded that the alloy the U-6Zr when viewed from the chemical composition can still be used for fuel research reactor. Residual hydrogen still found in small quantities in the U-6Zr powder that can be eliminated by heating for longer. Reaction between Zr with residual hydrogen to form the αZ phase is accompanied exothermic reaction with brought out heat of 93 449 cal/g.