Thermal Analysis of Compact Fuel Element in HTGRs Based on Two-Temperature Homogenized Model
A two-temperature homogenization model was proposed to facilitate thermal analysis of heterogeneous fuel elements in high temperature gas-cooled reactors (HTGRs). It has been applied to a fuel pebble in pebble-bed type HTGRs and shows good performance. In this paper, this model is extended to cylindrical geometry to model the fuel compact in block type design of HGTRs. For a given fuel compact design, homogenized parameters are obtained at steady-state through matching the analytic solution for the homogenized fuel compact to the reference solution of the heterogeneous fuel compact. The reference solutions are provided by the Monte Carlo method, as the “meshless Monte Carlo method can treat problems with multiple levels of heterogeneity and complicated structure well while the usual numerical methods in heat transfer problems (such as the finite difference or finite element) are based on discretized mesh systems and thus inherently limited in the geometry treatment. Several sensitivity tests were performed and the homogenized parameters are numerically insensitive to boundary conditions and important reactor operating conditions. Steady state and transient thermal analyses of a fuel compact are presented based on this two-temperature homogenized model. Compared to the simple volumetric-average thermal conductivity approach currently in use in the literature, this model gives more realistic temperature distribution and provides the fuel-kernel and graphite-mixture temperatures separately. The availability of fuel-kernel temperature distribution allows incorporation of Doppler temperature feedback in nuclear analysis. A reactor point kinetics model is subsequently coupled with the two-temperature thermal transient model for more accurate neutronics evaluation with Doppler temperature feedback. Several test scenarios are studied, including external reactivity insertion and coolant cooldown events.
Fuel Compact Monte Carlo Hybrid Method Two-Temperature Homogenized Model Temperature Feedback Stationary Transient Verification Validation HTGRs
Hui Yu Nam Zin Cho
Korea Advanced Institute of Science and Technology 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea
国际会议
上海
英文
976-987
2010-10-10（万方平台首次上网日期，不代表论文的发表时间）