The uranium obtained after reprocessing spent nuclear fuel can be reused. Photo Credit: Lukas Lehotsk |
UrFU scientists have discovered that the use of gallium and indium can make the process of pyrochemical reprocessing of nuclear fuel cheaper while maintaining its efficiency. This technology uses molten salts and liquid gallium to separate components of spent nuclear fuel (SNF). To make the process cheaper, the physicists added indium: the technology remained as effective, but the cost of reprocessing itself decreased. The results of the study will help modernize current SNF reprocessing methods and make them more efficient. Full details of the study are published in Alloys.
"This method has many advantages, in particular it focuses on the reprocessing of high-activity, low-life nuclear fuel with a high burn-up depth, which cannot be achieved by other methods such as water technology. It is also environmentally safer, as the amount of radioactive waste after reprocessing is reduced. Gallium can be used in fuel reprocessing by this method, but we have found that by adding indium, the reprocessing efficiency remains as high, but the cost of the process is reduced," explains Alexander Dedyukhin, senior engineer at the Department of Rare Metals and Nanomaterials at UrFU.
SNF consists primarily of uranium compounds, but plutonium and fission products are also present. After the spent fuel is dissolved in a salt melt, it is brought into contact with a liquid alloy based on gallium and indium, resulting in a redistribution of the components - uranium is concentrated in the metal, while unnecessary fission products remain in the salt. The use of metal alloys in nuclear fuel reprocessing is still being studied, but it is known that this technology can reduce the residence time of radioactive waste and make the process faster and safer for the environment.
"The use of molten salts with liquid metal alloys makes it possible to reduce the storage time of nuclear fuel. And one of the advantages is that it usually produces less radioactive waste than water technology," says Alexander Dedyukhin.
The scientists conducted experiments and produced three gallium-indium-based alloys containing 21.8 percent, 40 percent, and 70 percent indium. The scientists recorded the solubility of nuclear fuel using the precipitation method, which involves sampling a saturated liquid metal solution for chemical analysis. The study showed that the separation efficiency of uranium and nuclear fuel components using gallium- and indium-based alloys is high, but decreases slightly as the amount of indium in the alloy increases.
Published in journal: Alloys
Additional information: Gallium is a silvery-white metal that has high thermal conductivity. The melting point of gallium is 29.76℃, which makes it liquid at room temperature. Because of this, this metal is widely used in thermometers, as well as in solar panels, semiconductor industry, LED manufacturing and as a catalyst in various chemical technologies such as nuclear industry.
Indium is a soft silvery-white metal with a low melting point and high electrical conductivity. The main sources of indium are ores of zinc, tin and iron. Indium is an important element in electronics, optics and other industrial sectors. Due to its unique properties, it finds application in the development of modern microelectronics.
Source/Credit: Ural Federal University | Sergey Lukyanchenko
Reference Number: tn110723_01