Materials Reports  2019, Vol. 33 Issue (Z2): 130-133 |
| INORGANIC MATERIALS AND CERAMIC MATRIX COMPOSITES |
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| Simulation of Thermophysical Properties of UO2-Er2O3 Fuel by Molecular Dynamics |
| LIU Yu, XIAO Hongxing, ZHANG Xiang, ZENG Qiang, LIU Zhe, LENG Ke, MA Liang
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| Nuclear Power Institute of China, Chengdu 610213 |
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Abstract In order to maintain the smooth operation of the nuclear fission reaction in the reactor, it is necessary to add burnable poison to the fuel elements of the reactor, which could absorb a large amount of thermal neutrons in the initial stage of the reactor operation to suppress the fission of the nuclear fuel. And in the later stages of reactor operation, as the burnable poison are gradually consumed, the number of thermal neutrons increases, which can compensate for the gradual decrease in reactivity due to the reduction of fissile nuclide, thereby maintaining the smooth operation of the nuclear fission reaction throughout the operating life of the reactor. At present, the main burnable poisons used in the reactor are Gd2O3 and ZrB2, as the fuel burnup increases, the consumption of burnable poison and fuel burnup are difficult to match due to the excessive consumption of Gd2O3 and ZrB2. Er2O3 is considered to be suitable for fuel elements with high fuel burnup and long life in the future due to its slow bur-ning, stability, and low reactivity penalty. Using Er2O3 as burnable poisonous to improve fuel enrichment can improve fuel discharge and fuel consumption, improve fuel utilization and reduce nuclear power operation costs.
In this paper, the thermophysical properties of fuel pellets with Er2O3 content of 6 mol% were simulated by molecular dynamics method. The theoretical model of UO2-6mol%Er2O3 burnable poisonous fuel pellets was established. Based on this, the thermophysical properties of UO2-6mol%Er2O3 fuel pellets were calculated, including lattice lattice parameters, thermal expansion coefficient, specific heat capacity and thermal conductivity of the fuel pellets. Research shows that: (1) The lattice lattice parameters of UO2-6mol%Er2O3 fuel increase linearly with increasing temperature, satisfying the mathematical relationship of a(T)=0.542 65+5.717 06×10-6T-3.674 98×10-10T2+3.432 3×10-13T3(nm). (2) The thermal expansion coefficient of UO2-6%Er2O3 fuel increased with the increase of temperature, and the increase rate increased with the increase of temperature. The relationship between the average thermal expansion coefficient and temperature of the fuel crystal relative to 300K was γ=1. 028 449×10-5-3.556 13×10-10T+5.730 38×10-13T2(K-1). (3) The specific heat capacity of UO2-6mol%Er2O3 fuel increased with the increase of temperature, and the increase rate decreased with the increase of temperature, which satisfied Cp(J·mol-1·K-1)=47.545+51.276 6×10－3·T－17.191 3×10－6·T2. (4) The thermal conductivity of UO2-6%Er2O3 fuel decreased with increasing temperature, which satisfied k=10.145+1.185×10－4·T .
In this paper, the lattice parameters, thermal expansion coefficient, specific heat capacity and thermal conductivity of UO2-6%Er2O3 fuel were calculated by molecular dynamics method. Through theoretical calculations, it provided support for further research and engineering applications of Er2O3 burnable poisonous fuels.
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Published: 25 November 2019
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| About author:: Yu Liu, received his M.S. degrees in June 2018 from Unclear Power Institute of China, focusing on the research in the field of nuclear fuel cycle and materials. |
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1 娄磊,姚栋,柴晓明,等.科技创新导报,2018(22),44.
2 黄世恩,杨平,汪量子,等.核动力工程,2017,38(2),6.
3 赵传奇,曹良志,吴宏春,等.原子能科学技术,2016,50(8),1433.
4 强胜龙,秦冬,柴晓明,等.核动力工程,2014,35(2),1.
5 李满仓,刘仕倡,秦冬,等.原子能科学技术,2019(7),1188.
6 刘羽,张翔,杨静,等.核动力工程,2014,39(5),47.
7 Kim S H, Kim Y G, Kim H S, et al. Journal of Nuclear Materials,2005,342,119.
8 Yamanaka S, Kurosaki K. Katayama M,et al. Journal of Nuclear Mate-rials,2009,389(1),115.
9 Wei X, Pan W, Cheng L F, et al. Solid State Ionics,2009,180(1),13. |
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