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Title: Multi-componenet diffusion analysis and assessment of Gamma code and improved RELAP5 code

Abstract

A loss-of-coolant accident (LOCA) has been considered a critical event for very high temperature gas-cooled reactor (VHTR). Following helium depressurization, it is anticipated that unless countermeasures are taken, air will enter the core through the break by molecular diffusion and ultimately by natural convection leading to oxidation of the in-core graphite structure. Thus, without any mitigating features, a LOCA will lead to an air ingress event, which will lead to exothermic chemical reactions of graphite with oxygen, potentially resulting in significant increases of the core temperature. New and safer nuclear reactors (Generation IV) are now in the early planning stages in many countries throughout the world. One of the reactor concepts being seriously considered is the VHTR. To achieve public acceptance, these reactor concepts must show an increased level of inherent safety over current reactor designs (i.e., a system must be designed to eliminate any concerns of large radiological releases outside the site boundary). A computer code developed from this study, gas multi-component mixture analysis (GAMMA) code, was assessed using a two-bulb experiment and in addition the molecular diffusion behavior in the prismatic-core gas-cooled reactor was investigated following the guillotine break of the main pipe between the reactor vessel andmore » the power conversion unit. The RELAP5 code was improved for the VHTR air ingress analysis and was assessed using inverse U-tube and NACOK natural circulation data.« less

Authors:
Publication Date:
Research Org.:
Idaho National Laboratory (INL)
Sponsoring Org.:
DOE - NE
OSTI Identifier:
915516
Report Number(s):
INL/JOU-06-11845
TRN: US0804998
DOE Contract Number:  
DE-AC07-99ID-13727
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Engineering & Design; Journal Volume: 237; Journal Issue: 10
Country of Publication:
United States
Language:
English
Subject:
99 - GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; AIR; CHEMICAL REACTIONS; COMPUTER CODES; DIFFUSION; GAS COOLED REACTORS; LOSS OF COOLANT; NATURAL CONVECTION; REACTOR VESSELS; VHTR, thermal hydraulics

Citation Formats

Chang Oh. Multi-componenet diffusion analysis and assessment of Gamma code and improved RELAP5 code. United States: N. p., 2007. Web.
Chang Oh. Multi-componenet diffusion analysis and assessment of Gamma code and improved RELAP5 code. United States.
Chang Oh. Tue . "Multi-componenet diffusion analysis and assessment of Gamma code and improved RELAP5 code". United States. doi:.
@article{osti_915516,
title = {Multi-componenet diffusion analysis and assessment of Gamma code and improved RELAP5 code},
author = {Chang Oh},
abstractNote = {A loss-of-coolant accident (LOCA) has been considered a critical event for very high temperature gas-cooled reactor (VHTR). Following helium depressurization, it is anticipated that unless countermeasures are taken, air will enter the core through the break by molecular diffusion and ultimately by natural convection leading to oxidation of the in-core graphite structure. Thus, without any mitigating features, a LOCA will lead to an air ingress event, which will lead to exothermic chemical reactions of graphite with oxygen, potentially resulting in significant increases of the core temperature. New and safer nuclear reactors (Generation IV) are now in the early planning stages in many countries throughout the world. One of the reactor concepts being seriously considered is the VHTR. To achieve public acceptance, these reactor concepts must show an increased level of inherent safety over current reactor designs (i.e., a system must be designed to eliminate any concerns of large radiological releases outside the site boundary). A computer code developed from this study, gas multi-component mixture analysis (GAMMA) code, was assessed using a two-bulb experiment and in addition the molecular diffusion behavior in the prismatic-core gas-cooled reactor was investigated following the guillotine break of the main pipe between the reactor vessel and the power conversion unit. The RELAP5 code was improved for the VHTR air ingress analysis and was assessed using inverse U-tube and NACOK natural circulation data.},
doi = {},
journal = {Nuclear Engineering & Design},
number = 10,
volume = 237,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}