Electrodeposition of uranium is a common practice to create samples for alpha spectrometry and it could be an alternative way to produce irradiation LEU targets to fabricate radiopharmaceuticals as 99Mo used for cancer diagnosis. Usually electrodeposition of uranium uses ionic or aqueous solutions to produce uranium deposits in less acidic electrolytes (pH>2.5). During uranium electrodeposition, there is a high competition with H2 evolution, once cathodic potentials are very high. In less acidic electrolyte the electrodeposition is uranyl hydroxyl and uranium oxides compounds, formed directly from uranyl (U-VI) structure. A reliable regression equation (R2=0.836) for alpha emission activity of uranium deposition was obtained, based on cell temperature and electrodeposition time. The deposition has oxide/hydroxide nature, acting as insulator during electrochemical process. The maximum level of deposited uranium, in terms of alpha activity, was around 34 Bq.cm-2 (-1.8 VAg/AgCl, 2000 s, 60°C). In this condition, the inferred maximum amount of uranium was ~5.4 mg [U] /cm2, which might be interesting to build probe samples to simulate irradiation targets.
Powdered uranium silicide (U3Si2) 20% U235 enriched is an intermetallic compound used
as nuclear fuel material dispersed in aluminum to be the meat of fuel elements. U3Si2 powder is the
state-of-the-art as nuclear fuel material mostly used in modern research reactors. Its recent
established fabrication in IPEN replaced the previous ceramic powder U3O8 used in the fuel of IEAR1
(IPEN/CNEN, São Paulo, Brazil). The U3Si2 is a compound with 92.3%wtU and 7.7%wtSi. Its
production is made by induction furnace melting using metallic uranium, produced by
magnesiothermic reaction, and pure silicon. The induction furnace melts under argon controlled
environment using zirconia crucible. Homogenization of liquid bath at 1800°C is a compromise
between crucible resistance and homogenized melting, avoiding hazardous happenings. IPEN
produced its first lot of enriched U3Si2 in September 2004, with a continuous fabrication ever since.
This research work represents the ability of having fully Brazilian supply of this strategic and high
cost nuclear material. The fuel quality meets the world quality standards required by International
Atomic Energy Agency (IAEA) and RERTR standards. Brazilian production of U3Si2 powder not
only closed the fuel cycle, from uranium mineral to fuel element, but also allowed higher
productivity of nuclear medicine radioisotopes by IEA-R1.
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