Short Communication on “In-situ TEM ion irradiation investigations on U3Si2 at LWR temperatures”

Abstract

The radiation-induced amorphization of U 3 Si 2 was investigated by in-situ transmission electron microscopy using 1 MeV Kr ion irradiation. Both arc-melted and sintered U 3 Si 2 specimens were irradiated at room temperature to confirm the similarity in their responses to radiation. The sintered specimens were then irradiated at 350 • C and 550 • C up to 7.2×10 15 ions/cm 2 to examine their amorphization behavior under light water reactor (LWR) conditions. U 3 Si 2 remains crystalline under irradiation at LWR temperatures. Oxidation of the material was observed at high irradiation doses.

Radiation-induced grain subdivision and bubble formation in U3Si2 at LWR temperature

“…The transition of micron-sized U 3 Si 2 to nano-sized UO 2 was also observed upon different ion irradiations (e.g., 1 MeV Kr 2+ ) in the same facility at the same temperature [8]. In their experiment, the formation of nano-sized UO 2 from U 3 Si 2 upon irradiation was attributed to irradiation enhanced/induced oxidation due to the fact that part of the sample which was shielded from irradiation by sample grid remains crystalline U 3 Si 2 .…”

“…Limited ion beam bombardment experiments were performed on U 3 Si 2 at low-temperature regimes [7] with key observations including follows: (1) U 3 Si 2 is sensitive to radiation-induced amorphization at low temperature, and the critical amorphization dose is 0.38 dpa (1.5 MeV Kr + irradiations) or 1.1x10 23 fissions/cm 3 (neutron irradiation) at 30 °C; (2) A 2.2% volume contraction observed for U 3 Si 2 upon radiation-induced amorphization, potentially beneficial for suppressing fission gas mobility; (3) a threshold temperature of 250 °C existing at a dose rate of 1.5×10 -3 dpa/s, above which no amorphization can occur. Very recently, Miao [8] studied irradiation of U 3 Si 2 using 1 MeV Kr 2+ at 350 °C and 550 °C, temperatures predicted by BISON code [9] respectively for U 3 Si 2 pellet rim and center in LWR condition at a burnup of 30-50 MWD/MTU. In this study, the irradiation behavior of U 3 Si 2 was investigated by 300 keV Xe + ion beam at 350 °C and the microstructure evolution was studied by in-situ TEM observation.…”

Rate theory modeling a vacancy mediated intra-granular fission gas bubbles growth in amorphous $U_3Si_2$

“…It is related to a differences in swelling mechanism in research reactors and commercial LWR caused by amorphization scenario: fission-induced amorphization affecting the swelling [18] can be suppressed at much high operating temperatures in LWRs (see Refs. [6][7][8][9][10][11][12][13]).…”

The use of gadolinium as a burnable poison within U3Si2 fuel pellets

“…The use of uranium silicide fuels brings a number of challenges, many of which are being explored in current research. These include manufacture [1,2], thermal performance [3] and irradiation response [4,5]. In order to be commercially viable in current plant designs, several further challenges must be addressed.…”