Uranium Dioxide Nanoparticulated Materials

Abstract

Nanostructured actinide materials have gained the attention of the nuclear community after the discovery of enhanced properties in fuels that undergo high burn up. On these conditions, the UO 2 grains experimented recrystallization and formed a new rim of UO 2 nanoparticles, called high burn up structures (HBS). The pellets with HBS showed closed porosity with better fission gas retention and radiation tolerance, ameliorated mechanical properties, and less detriment of the thermal conductivity upon use. In this chapter, we will review different ways to obtain uranium nanoparticles, with emphasis on their synthesis and characterization. On the one hand, we will comment on radiation chemical syntheses, organic precursor-assisted syntheses, denitration processes, and biologically mediated syntheses. On the other hand, we will include for each of them a reference to the appropriate tools of the materials science that are used to fully characterize physical and chemical properties of these actinide nanoparticles.

Impact of Surface Oxidation on the Morphology of Uranium Dioxide Nanoparticles

“…UO 2 and ThO 2 are essential compounds in the nuclear field and the understanding of their nanocrystalline forms is crucial due to their novel properties and for their presence in the environment. 38,39 UO 2 NCs form naturally in the nuclear fuel cycle. Furthermore, actinide oxide NCs show better fission gas retention, radiation tolerance, mechanical properties, higher thermal conductivity, higher melting point, and chemical stability and are highly abundant.…”

“…Furthermore, actinide oxide NCs show better fission gas retention, radiation tolerance, mechanical properties, higher thermal conductivity, higher melting point, and chemical stability and are highly abundant. 38,39 UO 2 and ThO 2 NCs are synthesized using a bottom-up approach via a nonaqueous thermal technique. [26][27][28]38,39 In this process, metal precursors, such as uranyl acetylacetonate (UO 2 (ACAC) 2 ) or thorium acetylacetonate (ThO 2 (ACAC) 2 ), are introduced in a mixture of dibenzyl ether with different capping agents: oleic acid (OA), oleylamine (OAm), and trioctylphosphine oxide (OP(Oct) 3 ).…”

“…38,39 UO 2 and ThO 2 NCs are synthesized using a bottom-up approach via a nonaqueous thermal technique. [26][27][28]38,39 In this process, metal precursors, such as uranyl acetylacetonate (UO 2 (ACAC) 2 ) or thorium acetylacetonate (ThO 2 (ACAC) 2 ), are introduced in a mixture of dibenzyl ether with different capping agents: oleic acid (OA), oleylamine (OAm), and trioctylphosphine oxide (OP(Oct) 3 ).…”