Development and Application of a Mechanical Model for Multilayer Anisotropic Cladding
-
摘要: 由高致密度纯SiC和SiC纤维/基体复合材料(SiCf/SiC)组成的多层SiC复合包壳是当前事故容错燃料(ATF)包壳的热门选型,当前应用的典型燃料性能分析程序缺乏对于SiCf/SiC材料各向异性力学行为的建模能力,为提高燃料性能分析中复合SiC包壳力学计算的准确性,本文开发了一套适用于多层各向异性材料的力学模型,并将其集成到燃料性能分析程序FRAPCON4.0中,采用多层SiC包壳热力耦合算例对模型正确性进行了验证。实现了对具有正交各向异性力学特性和多轴类塑性行为的SiC复合包壳的力学计算功能,分析了双层SiC包壳燃料元件堆内稳态运行工况的性能。本研究建立的力学模型适用于任意多层圆柱结构燃料元件,并具备正交各向异性力学参数及行为的分析能力,可应用于多种新型燃料元件分析。
-
关键词:
- SiC包壳 /
- 事故容错燃料(ATF) /
- 芯块-包壳机械相互作用(PCMI) /
- 各向异性材料
Abstract: The multilayer SiC composites cladding composed of monolithic SiC and SiC fiber/matrix composite (SiCf/SiC) is a popular choice for accident-tolerant fuel cladding. However, typical fuel performance analysis codes currently lack the modeling capability for the anisotropic mechanical behavior of SiCf/SiC materials. In order to enhance the precision of mechanical calculations for composite SiC cladding in fuel performance analysis, a mechanical model was developed for multilayer anisotropic materials and integrated into the fuel performance analysis code FRAPCON4.0. Validation of the model's accuracy was conducted using a multilayer SiC cladding thermal-mechanical coupling case. The mechanical calculation capability for SiC composite cladding with orthotropic mechanical properties and multiaxial pseudoplastic behavior was achieved, and the performance of duplex-layer SiC cladding fuel elements under normal operation condition was analyzed. The developed mechanical model in this study is adaptable to arbitrary multilayer cylindrical structure fuel elements and has the capability to analyze orthotropic mechanical parameters and behaviors, rendering it applicable to various types of novel fuel element analyses. -
表 1 验证算例采用的CMC及CVD型SiC材料参数
Table 1. Material Prameters of CMC and CVD SiC in Validation Case
材料 参数 数值 CMC型SiC Er/GPa 95.5 Eθ/GPa 201 Ez/GPa 173 νrθ 0.248 νrz 0.242 νθz 0.175 G/GPa 62.4 热导率/(W·m–1·K−1) 2 热膨胀系数 2×10−6 CVD型SiC E/GPa 460 ν 0.21 热导率/(W·m–1·K−1) 10 热膨胀系数 2×10−6 表 2 燃料棒设计参数和运行条件
Table 2. Design Parameters and Operation Conditions of Fuel Rod
参数 数值 Zr-4包壳外径/mm 9.48 Zr-4包壳厚度/mm 0.56 SiC包壳外径/mm 9.76 SiC包壳(CMC/CVD)厚度/mm 0.45/0.25 芯块直径/mm 8.192 活性区高度/m 3.6576 气腔长度/m 0.175 初始内压/MPa 2.41 冷却剂压力/MPa 15.51 冷却剂入口温度/K 565.7 冷却剂质量流量/(kg·m–2·s−1) 3434.5 -
[1] TERRANI K A. Accident tolerant fuel cladding development: promise, status, and challenges[J]. Journal of Nuclear Materials, 2018, 501: 13-30. [2] KATOH Y, OZAWA K, SHIH C, et al. Continuous SiC fiber, CVI SiC matrix composites for nuclear applications: properties and irradiation effects[J]. Journal of Nuclear Materials, 2014, 448(1-3): 448-476. [3] LEE Y, KAZIMI M S. A structural model for multi-layered ceramic cylinders and its application to silicon carbide cladding of light water reactor fuel[J]. Journal of Nuclear Materials, 2015, 458: 87-105. [4] KATOH Y, SNEAD L L. Silicon carbide and its composites for nuclear applications - Historical overview[J]. Journal of Nuclear Materials, 2019, 526: 151849. [5] SNEAD L L, NOZAWA T, KATOH Y, et al. Handbook of SiC properties for fuel performance modeling[J]. Journal of Nuclear Materials, 2007, 371(1-3): 329-377. [6] KATOH Y, NOZAWA T, SNEAD L L, et al. Stability of SiC and its composites at high neutron fluence[J]. Journal of Nuclear Materials, 2011, 417(1-3): 400-405. [7] SUKJAI Y. Silicon carbide performance as cladding for advanced uranium and thorium fuels for light water reactors[D]. Cambridge: Massachusetts Institute of Technology, 2014. [8] BEN-BELGACEM M, RICHET V, TERRANI K A, et al. Thermo-mechanical analysis of LWR SiC/SiC composite cladding[J]. Journal of Nuclear Materials, 2014, 447(1-3): 125-142. [9] DENG Y B, SHIRVAN K, WU Y W, et al. Probabilistic view of SiC/SiC composite cladding failure based on full core thermo-mechanical response[J]. Journal of Nuclear Materials, 2018, 507: 24-37. [10] RHO H, LEE Y. Development of a 2D axisymmetric SiC cladding mechanical model and its applications for steady-state and LBLOCA analysis[J]. Journal of Nuclear Materials, 2022, 558: 153311. [11] 邓阳斌,贺亚男,巫英伟,等. 多层结构包壳和非刚体芯块力学建模及应用[J]. 原子能科学技术,2018, 52(7): 1308-1315. doi: 10.7538/yzk.2017.youxian.0611 [12] DENG Y B, WU Y W, QIU B W, et al. Development of a new Pellet-Clad Mechanical Interaction (PCMI) model and its application in ATFs[J]. Annals of Nuclear Energy, 2017, 104: 146-156. [13] HE Y N, SHIRVAN K, WU Y W, et al. Fuel performance optimization of U3Si2-SiC design during normal, power ramp and RIA conditions[J]. Nuclear Engineering and Design, 2019, 353: 110276.