Evolution of dispersed fuel used for research and test reactors

Abstract

Currently, 222 research reactors are operating in 53 countries in Brazil, four units. Nuclear fuel type used in research reactors depends on the thermal power level, classified by power classes, such as critical and subcritical units operating below 1Kw, working from 1 kW to 1 MW, and over 1 Mw, being 28 facilities operating on a medium power spectrum from 1 MW up to 10Mw. Alternatively, they divided the research reactor into lowenriched uranium below 20% of U-235 and highly-enriched uranium over this limit. In the 1950s, the superheat section of the Fifth Boiling Reactor Experiment (BORAX-V) used enriched uranium (93 wt.% U-235) as uranium dioxide in a matrix of stainless steel. In sequence, it divided a fast dispersion fuel evolution into three ages. The 1950s predominated U–Al alloy. In the 1960s, the U3 O8 –Al and UAlx -Al followed the 1980s, focusing on high uranium density up to 4.8 gU/cm3 planned to U3 Si2 -Al and U10Mo/Al. Today, global research focuses on U-10Mo dispersion and monolithic forms. Many thermal physical features of dispersed fuels can help define the application field, mainly focused on neutron activation analysis and radiopharmaceutical production.