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

Abstract

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 thesemore » 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.« less

Authors:
Publication Date:
Research Org.:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org.:
DOE - NE
OSTI Identifier:
1046070
Report Number(s):
INL/EXT-12-24603
TRN: US1203743
DOE Contract Number:  
DE-AC07-05ID14517
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; CONTROL ELEMENTS; DESIGN; EFFICIENCY; FORECASTING; GRAPHITE; IRRADIATION; LIFE CYCLE; MANUFACTURING; PERFORMANCE; SIMULATION; TARGETS; VALIDATION; BYPASS LFOW; ineri; KAERI; NGNP

Citation Formats

Schultz, Richard. Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor. United States: N. p., 2012. Web. doi:10.2172/1046070.
Schultz, Richard. Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor. United States. https://doi.org/10.2172/1046070
Schultz, Richard. 2012. "Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor". United States. https://doi.org/10.2172/1046070. https://www.osti.gov/servlets/purl/1046070.
@article{osti_1046070,
title = {Experimental and Analytic Study on the Core Bypass Flow in a Very High Temperature Reactor},
author = {Schultz, Richard},
abstractNote = {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.},
doi = {10.2172/1046070},
url = {https://www.osti.gov/biblio/1046070}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {4}
}