It can be used to produce mixed oxide uranium-plutonium nuclear fuel (MOX-fuel) for the Russian design reactors.
All the existing methods of producing uranium-plutonium MOX-fuel have certain drawbacks. Such drawbacks include the difficulty of obtaining homogeneous composites, the required use of high temperatures and explosive hydrogen or low thermal stability of the mixture obtained.
In October 2016 Rosatom's JSC VNIINM (The Bochvar High-Technology Institute for Inorganic Materials) patented its method of producing solid plutonium dioxide solution in uranium dioxide matrix that can be used to produce MOX-fuel. It is based on the reaction of nitrate solutions of uranium and plutonium with hydrazine hydrate to obtain amorphous compound of uranium and plutonium. The compound is kept in the mother solution at 80-90°С for a period of five hours to obtain precipitation of fine powder in the form of homogeneous mixture of hydrated oxides of uranium and plutonium. The obtained precipitation is heated at 300°С to produce the final product.
Plutonium presence in the uranium dioxide matrix stabilizes the crystal structure to such a degree that even after the solid plutonium dioxide solution in the uranium dioxide matrix is heated up to 800°С only one homogeneous mixture of the two oxides (U, Pu)O2 can be found.
