Ion beam radiation effects in monazite

Abstract

a b s t r a c tMonazite is a potential matrix for conditioning minor actinides arising from spent fuel reprocessing. The matrix behavior under irradiation must be investigated to ensure long-term containment performance. Monazite compounds were irradiated by gold and helium ions to simulate the consequences of alpha decay. This article describes the effects of such irradiation on the structural and macroscopic properties (density and hardness) of monazites LaPO 4 and La 0.73 Ce 0.27 PO 4 . Irradiation by gold ions results in major changes in the material properties. At a damage level of 6.7 dpa, monazite exhibits volume expansion of about 8.1%, a 59% drop in hardness, and structure amorphization, although Raman spectroscopy analysis shows that the phosphate-oxygen bond is unaffected. Conversely, no change in the properties of these compounds was observed after He ion implantation. These results indicate that ballistic effects predominate in the studied dose range.

Site-selective time resolved laser fluorescence spectroscopy of Eu and Cm doped LaPO4

“…Natural monazite [10,11] and (La,An)PO 4 [12] have been shown to be radiation tolerant to high alpha doses. This has been attributed to an alpha-annealing process that enables monazite to recover crystallinity under irradiation [13][14][15][16]. It has also been demonstrated that it is possible to synthesize single phase Pu and Am containing monazite in a method that can be adapted to a hot cell environment through the use of NH 4 H 2 PO 4 [7].…”

New insights into phosphate based materials for the immobilisation of actinides

“…Nasdala et al [231] and Picot et al [232] studied the behaviour of CePO 4 under 1-7 MeV Au ion irradiation at total fluences of 0.6 · 10 13 -5.1 · 10 13 ions · cm −2 showing an amorphisation at highest dose. Recently, Ji et al [191] reported the amorphisation of a La 0.2 Gd 0.8 PO 4 solid solution at a fluence of ~10 13 ions · cm −2 using 100 MeV Au swift heavy ion irradiation at room temperature.…”

He and Au ion radiation damage in sodalite, Na4Al3Si3O12Cl

“…Density variations were determined from the irradiation-induced step height on the sample surface following a similar method described in Refs. [17][18][19].…”