Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor

Richard Schultz

关键词: CONTROL ELEMENTS;    DESIGN;    EFFICIENCY;    FORECASTING;    GRAPHITE;    IRRADIATION;    LIFE CYCLE;    MANUFACTURING;    PERFORMANCE;    SIMULATION;    TARGETS;    VALIDATION BYPASS LFOW;    ineri;    KAERI;    NGNP;   

DOI  :  10.2172/1046070
RP-ID  :  INL/EXT-12-24603
PID  :  OSTI ID: 1046070
Others  :  TRN: US1203743

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

Core bypass flow has been one of key issues in the very high temperature reactor (VHTR) design for securing core thermal margins and achieving target temperatures at the core exit. The bypass flow in a prismatic VHTR core occurs through the control element holes and the radial and axial gaps between the graphite blocks for manufacturing and refueling tolerances. These gaps vary with the core life cycles because of the irradiation swelling/shrinkage characteristic of the graphite blocks such as fuel and reflector blocks, which are main components of a core's structure. Thus, the core bypass flow occurs in a complicated multidimensional way. The accurate prediction of this bypass flow and counter-measures to minimize it are thus of major importance in assuring core thermal margins and securing higher core efficiency. Even with this importance, there has not been much effort in quantifying and accurately modeling the effect of the core bypass flow. The main objectives of this project were to generate experimental data for validating the software to be used to calculate the bypass flow in a prismatic VHTR core, validate thermofluid analysis tools and their model improvements, and identify and assess measures for reducing the bypass flow. To achieve these objectives, tasks were defined to (1) design and construct experiments to generate validation data for software analysis tools, (2) determine the experimental conditions and define the measurement requirements and techniques, (3) generate and analyze the experimental data, (4) validate and improve the thermofluid analysis tools, and (5) identify measures to control the bypass flow and assess its performance in the experiment.