Abstract
A High Temperature Reactor can be designed to remove the decay heat without using any active systems. For most accident scenarios a release of radioactive fission products can be excluded by design. However, during operation of a HTR some accidents are principally possible, which can result in a release of fission products out of the fuel elements and of the reactor system. One of these accidents is a hypothetical massive air ingress into the hot graphite reactor core. After a pressure drop caused by leakages in the primary circuit a gas mass flow may be able to stream through the core according to free natural convection leading to a corrosion of the graphite fuel elements and reflector structures. With the VELUNA-experiment a testing device was installed, which allows to investigate the corrosion process on parts of a reactor core under real accident conditions. With regard to the experimental results already existing equations to calculate the chemical reaction rate in a pebble bed were modified and the applicability was demonstrated. These equations consider the chemical reaction in the porous graphite as well as diffusion processes to the graphite surface. Equivalent correlations were developed for different flow geometries and for the graphite
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Citation Formats
Roes, J.
Experimental investigations of graphite corrosion and aerosol formation during air ingress into the core of a high temperature pebble bed reactor; Experimentelle Untersuchungen zur Graphitkorrosion und Aerosolentstehung beim Lufteinbruch in das Core eines Kugelhaufen-Hochtemperaturreaktors.
Germany: N. p.,
1994.
Web.
Roes, J.
Experimental investigations of graphite corrosion and aerosol formation during air ingress into the core of a high temperature pebble bed reactor; Experimentelle Untersuchungen zur Graphitkorrosion und Aerosolentstehung beim Lufteinbruch in das Core eines Kugelhaufen-Hochtemperaturreaktors.
Germany.
Roes, J.
1994.
"Experimental investigations of graphite corrosion and aerosol formation during air ingress into the core of a high temperature pebble bed reactor; Experimentelle Untersuchungen zur Graphitkorrosion und Aerosolentstehung beim Lufteinbruch in das Core eines Kugelhaufen-Hochtemperaturreaktors."
Germany.
@misc{etde_10121423,
title = {Experimental investigations of graphite corrosion and aerosol formation during air ingress into the core of a high temperature pebble bed reactor; Experimentelle Untersuchungen zur Graphitkorrosion und Aerosolentstehung beim Lufteinbruch in das Core eines Kugelhaufen-Hochtemperaturreaktors}
author = {Roes, J}
abstractNote = {A High Temperature Reactor can be designed to remove the decay heat without using any active systems. For most accident scenarios a release of radioactive fission products can be excluded by design. However, during operation of a HTR some accidents are principally possible, which can result in a release of fission products out of the fuel elements and of the reactor system. One of these accidents is a hypothetical massive air ingress into the hot graphite reactor core. After a pressure drop caused by leakages in the primary circuit a gas mass flow may be able to stream through the core according to free natural convection leading to a corrosion of the graphite fuel elements and reflector structures. With the VELUNA-experiment a testing device was installed, which allows to investigate the corrosion process on parts of a reactor core under real accident conditions. With regard to the experimental results already existing equations to calculate the chemical reaction rate in a pebble bed were modified and the applicability was demonstrated. These equations consider the chemical reaction in the porous graphite as well as diffusion processes to the graphite surface. Equivalent correlations were developed for different flow geometries and for the graphite material of the bottom reflector. The corrosion process forms an aerosol, which consists of graphite particles and a reaction gas phase. The formatted aerosol was characterized concerning its chemical and physical properties. Because the aerosol particles can support the release of fission products, measurements of aerosol parameters like particle mass concentration and particle size distribution provide important information to estimate the radiologic consequences of such an hypothetical air ingress accident. (orig.)}
place = {Germany}
year = {1994}
month = {Aug}
}
title = {Experimental investigations of graphite corrosion and aerosol formation during air ingress into the core of a high temperature pebble bed reactor; Experimentelle Untersuchungen zur Graphitkorrosion und Aerosolentstehung beim Lufteinbruch in das Core eines Kugelhaufen-Hochtemperaturreaktors}
author = {Roes, J}
abstractNote = {A High Temperature Reactor can be designed to remove the decay heat without using any active systems. For most accident scenarios a release of radioactive fission products can be excluded by design. However, during operation of a HTR some accidents are principally possible, which can result in a release of fission products out of the fuel elements and of the reactor system. One of these accidents is a hypothetical massive air ingress into the hot graphite reactor core. After a pressure drop caused by leakages in the primary circuit a gas mass flow may be able to stream through the core according to free natural convection leading to a corrosion of the graphite fuel elements and reflector structures. With the VELUNA-experiment a testing device was installed, which allows to investigate the corrosion process on parts of a reactor core under real accident conditions. With regard to the experimental results already existing equations to calculate the chemical reaction rate in a pebble bed were modified and the applicability was demonstrated. These equations consider the chemical reaction in the porous graphite as well as diffusion processes to the graphite surface. Equivalent correlations were developed for different flow geometries and for the graphite material of the bottom reflector. The corrosion process forms an aerosol, which consists of graphite particles and a reaction gas phase. The formatted aerosol was characterized concerning its chemical and physical properties. Because the aerosol particles can support the release of fission products, measurements of aerosol parameters like particle mass concentration and particle size distribution provide important information to estimate the radiologic consequences of such an hypothetical air ingress accident. (orig.)}
place = {Germany}
year = {1994}
month = {Aug}
}