Fracture toughness and fracture surface energy of sintered uranium dioxide fuel pellets

Crack tip plasticity in single crystal UO2: Atomistic simulations

“…However, the experimentally determined surface energies, for both inter-and intragranular fracture, are much higher than theoretical predictions, suggesting some deviation from ideal cleavage fracture behavior [5,9,11]. Indeed, the simulation results presented below reveal that crack tip shielding processes take place around the crack tips, leading to considerable increase in the energy release rates.…”

“…Both inter-and intragranular fracture modes are possible for polycrystalline UO 2 , and the contribution of intragranular fracture mode increases with increasing grain size and decreasing temperature [5,12]. The measured surface energies for the formation of new crack surfaces vary from a few to tens of J/m 2 , and are usually much higher than the theoretical predictions based on the Griffith theory [13], suggesting energy dissipation processes that may shield the crack extension [5,9,11]. These previous experiments, mostly done decades ago, provide the engineering scale understanding on the fracture behavior of UO 2 .…”

“…The fracture behavior of UO 2 has been extensively studied since the 1960s [5][6][7][8][9][10][11][12]. Most of the previous work has focused on polycrystalline UO 2 (sintered) as it is easy to prepare and is the form being used in nuclear reactors.…”

Mechanical properties at sub-microscale and macroscale of polycrystalline uranium mononitride

“…7, together with the literature data of UO 2 [33][34][35][36]. In the present study, the microcrack could not be observed below the load of 980 mN.…”

“…Load dependence of the fracture toughness of UN, together with the literature data of UO 2[33][34][35][36].…”