Interaction between voids and grain boundaries in UO2 by molecular-dynamics simulation

Chiang, Tsu Wu; Chernatynskiy, Aleksandr V.; Sinnott, Susan B.; Phillpot, Simon R.

doi:10.1016/j.jnucmat.2014.01.027

Cited by 12 publications

(5 citation statements)

References 40 publications

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“…The effect of porosity on thermal transport in UO 2 has not yet been directly characterized at the atomic level. While there are a few atomistic simulation studies of pores in UO 2 [33][34][35][36][37] , they have focused on phenomena such as migration under a thermal gradient 33 , thermomechanical properties 34 , interaction of the pores with each other 38 or with grain boundaries, 35 and re-solutioning of inert gases from bubbles in the lattice 36,37 2 Computational details…”

mentioning

confidence: 99%

Effect of pores and He bubbles on the thermal transport properties of UO2 by molecular dynamics simulation

Lee

Chernatynskiy

Shukla

et al. 2015

Journal of Nuclear Materials

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The thermal conductivities of UO 2 single crystals containing nanoscale size pores and He gas bubbles are calculated using non-equilibrium molecular dynamics as a function of pore size and gas density in the bubble. As expected, the thermal conductivity decreases as pore size increases, while the decrease in thermal conductivity is determined to be more substantial than the predictions of traditional analytical models by Loeb and Maxwell-Eucken. However, the recent model of Alvarez, which is applicable when the phonon mean-free path is comparable to the pore size, is able to quantitatively reproduce the simulation results. The thermal conductivity of UO 2 of the small pores considered here is reduced further when the pore is filled with He gas. This surprising result is due to the penetration of the helium atoms into the lattice where they act as phonon scattering centers.

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mentioning

confidence: 99%

Effect of pores and He bubbles on the thermal transport properties of UO2 by molecular dynamics simulation

Lee

Chernatynskiy

Shukla

et al. 2015

Journal of Nuclear Materials

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“…Then, mechanical properties and their evolution in the presence of irradiation-induced defects have been investigated [96]. The study of the effect of the microstructure, initiated in F-BRIDGE by the investigation of dislocations, grain boundaries and polycrystalline UO 2 , has also been extended and refined [97,98].…”

Section: Discussionmentioning

confidence: 99%

Linking atomic and mesoscopic scales for the modelling of the transport properties of uranium dioxide under irradiation

Bertolus

Freyss

Dorado

et al. 2015

Journal of Nuclear Materials

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“…发生脆性断裂, 进而导致部件失效, 造成安全事故. U 1-x Th x O 2 混合燃料的脆性断裂特征, 与Xiao等 [12] 、 Balboa等 [19] 和Zhang等 [30] 的MD模拟结果及Mo 等 [27] 的纳米压入结果相吻合. Feng等 [40] 873和1973 K高温下将UO…”

Section: 浓度与温度对力学性能的影响unclassified

“…等 [11,12] 研究了U 1-x Th x O 2 混合燃料的晶格常数、热膨胀系数、热导率、热容及焓在300-2100 K温度范围内的变化规律. 此外, 借助MD模拟可研究 UO 2 基混合燃料中晶界迁移、孔洞演化、气体扩散及级联碰撞过程 [13−16] .…”

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Effects of Th doping on mechanical properties of U1–xThxO2: An atomistic simulation

Xin¹,

Hong-Wei²,

Sun³

et al. 2021

Acta Phys. Sin.

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Since thorium (Th) owns high conversion ratio in thermal neutron spectrum, high melting temperature, high thermal conductivity and good corrosion resistance in high-temperature water, it can be doped into UO2 based fuel to initiate the fission reaction, and improve the physical properties of UO2. Owing to the challenging experimental conditions and technologies, molecular dynamics (MD) simulations are conducted to investigate the influences of Th doping on the mechanical properties of U1–xThxO2. The phase transition from initial fluorite structure to the metastable scrutinyite phase when loading along the [001] direction is observed, which accords well with the previous density functional theory calculations. However, if U1–xThxO2 is loaded along the [111] direction, only brittle fracture is observed. It is found that both the elastic modulus and fracture stress decrease linearly with elevating temperature but the fracture strain increases. As the Th concentration increases from 0 to 0.55, the elastic modulus first decreases and then increases; if the Th concentration is larger than 0.1, the fracture stress increases and the fracture strain decreases monotonically. The cracks are nucleated with an angle of 45º to the loading direction, propagate rapidly, and are characteristic of brittle fracture, which accords well with the classical failure criteria and experimental results for brittle materials. By comparison, the uniaxial tensile loading is also performed for polycrystalline U1–xThxO2. It is found that the elastic modulus and fracture stress decrease as the temperature increases. However, the elastic modulus is not sensitive to the Th concentration and the fracture increases as the Th concentration increases. The brittle intergranular fracture is observed in each of all polycrystalline samples. The obtained physical parameters are useful for designing the fuels in nuclear reactors.

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Interaction between voids and grain boundaries in UO2 by molecular-dynamics simulation

Cited by 12 publications

References 40 publications

Effect of pores and He bubbles on the thermal transport properties of UO2 by molecular dynamics simulation

Effect of pores and He bubbles on the thermal transport properties of UO2 by molecular dynamics simulation

Linking atomic and mesoscopic scales for the modelling of the transport properties of uranium dioxide under irradiation

Effects of Th doping on mechanical properties of U<sub>1–</sub><i><sub>x</sub></i>Th<i><sub>x</sub></i>O<sub>2</sub>: An atomistic simulation

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