Numerical simulations on self-leveling behaviors with cylindrical debris bed

Liancheng Guo, Koji Morita, Yoshiharu Tobita

研究成果: ジャーナルへの寄稿学術誌査読

13 被引用数 (Scopus)

抄録

The postulated core disruptive accidents (CDAs) are regarded as particular difficulties in the safety analysis of liquid-metal fast reactors (LMFRs). In the CDAs, core debris may settle on the core-support structure and form conic bed mounds. Then debris bed can be levelled by the heat convection and vaporization of surrounding coolant sodium, which is named “self-leveling behavior”. The self-leveling behavior is a crucial issue in the safety analysis, due to its significant effect on the relocation of molten core and heat-removal capability of the debris bed. Considering its complicate multiphase mechanism, a comprehensive computational tool is needed to reasonably simulate transient particle behavior as well as thermal-hydraulic phenomenon of surrounding fluid phases. The SIMMER program is a successful computer code initially developed as an advanced tool for CDA analysis of LMFRs. It is a multi-velocity-field, multiphase, multicomponent, Eulerian, fluid dynamics code coupled with a fuel-pin model and a space- and energy-dependent neutron kinetics model. Until now, the code has been successfully applied in numerical simulations for reproducing key thermal-hydraulic phenomena involved in CDAs as well as performing reactor safety assessment. However, strong interactions between massive solid particles as well as particle characteristics in multiphase flows were not taken into consideration in its fluid-dynamics models. To solve this problem, a new method is developed by combining the discrete element method (DEM) with the multi-fluid models of SIMMER code to reasonably simulate the particle behaviors as well as the thermal-hydraulic phenomena of multiphase fluid flows. In this paper, the coupling method is validated by performing numerical simulations on a series of experiments with cylindrical particle bed in 3D situation. Based on various experimental conditions, Reasonable agreement between simulation results and corresponding experimental data can demonstrate the applicability of the method in reproducing the self-leveling behavior of debris bed. Sensitivity analysis on some model parameters of DEM is also performed to assess their impacts in the simulation. It is expected that the present method can be used as a computational tool to estimate self-leveling process of debris beds as well as the following behaviors in real reactor environment.

本文言語英語
ページ(範囲)61-68
ページ数8
ジャーナルNuclear Engineering and Design
315
DOI
出版ステータス出版済み - 4月 15 2017

!!!All Science Journal Classification (ASJC) codes

  • 核物理学および高エネルギー物理学
  • 原子力エネルギーおよび原子力工学
  • 材料科学一般
  • 安全性、リスク、信頼性、品質管理
  • 廃棄物管理と処理
  • 機械工学

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