Manufacturing high-uranium-loaded dispersion fuel plates in Brazil

Author(s)

Durazzo, Michelangelo ; Souza, Jose Antonio Batista ; Carvalho, Elita Fontenele Urano de ; Restivo, Thomaz Augusto Guisard ; Genezini, Frederico Antonio ; Neto, Ricardo Mendes Leal

• Document type: Journal article
• Source: ANNALS OF NUCLEAR ENERGY; v. 200, p. 14-pg., 2024-02-06.

Abstract

The Nuclear and Energy Research Institute (IPEN-CNEN/SP) has developed and made available for routine production the technology for manufacturing dispersion-type fuel elements for research reactors. However, the fuel produced is limited to a uranium loading of 2.3 gU/cm3 (U3O8) or 3.0 gU/cm3 (U3Si2). To reduce Brazil's dependence on foreign sources of Mo-99, the Brazilian government plans to construct a new research reactor, the 30 MW open pool Brazilian Multipurpose Reactor (RMB), which will mainly produce domestic Mo-99. Lowenriched uranium fuel will be used in the RMB, and increasing uranium loading will be important to increase the reactor core's reactivity and fuel life. Uranium loadings of 3.2 gU/cm3 for the U3O8-Al and 4.8 gU/cm3 for the U3Si2-Al are considered the technological limit and have been well demonstrated worldwide. This work aimed to study the manufacturing process of these two highly uranium-loaded dispersion fuels and redefine current procedures. Additionally, UMo-Al dispersion fuel has been extensively studied globally and is likely to be the next commercially available technology. This new fuel utilizes a dispersion of UMo alloy with 7-10 wt% Mo, resulting in a uranium loading between 6 and 8 gU/cm3. We also studied this fuel type for potential use in the RMB research reactor. This work outlines the primary procedures for manufacturing these three types of fuels and the necessary adjustments to IPEN-CNEN/SP current technology. The manufacturing process proved to be well adapted to these new fuels, requiring only minor modifications. A comparison was made of the microstructures of fuel plate meat using three types of uranium compounds. The microstructures of U3Si2-Al and U10Mo-Al dispersions were found to be adequate, while that of U3O8-Al meat deviated significantly from the concept of an ideal dispersion. (AU)

• FAPESP's process: 07/07769-7 - High uranium density nuclear fuel for radioisotope/radiopharmaceutical producing reactors
• Grantee: Michelangelo Durazzo
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/13849-9 - Technology development for manufacturing UAlx-Al dispersion targets for nationalization of the 99Mo production by nuclear fission
• Grantee: Michelangelo Durazzo
• Support Opportunities: Regular Research Grants
• FAPESP's process: 21/14331-5 - Development of equipment for automated measurement of nuclear fuel plates
• Grantee: Michelangelo Durazzo
• Support Opportunities: Regular Research Grants