This title appears in the Scientific Report : 2001 

Bröckerhoff, Peter (Corresponding author)
Sicherheitsforschung für kerntechnische Anlagen; ISR-2
Jülich Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag 2001
152 p.
Berichte des Forschungszentrums Jülich 3911
Please use the identifier: in citations.
The inner surfaces of pressure vessels and hot gas ducts of gas-cooled nuclear power stations need internal insulation because of the high operating pressures and temperatures. They have to protect the pressure bearing walls from high temperatures. In addition, the thermal fluxes of the power stations should be low. Because of the high pressure the insulatiog systems have to be installed an the inner surfaces of the walls and not an the outer surfaces as in case of conventional stations. Therefore gas movement may occur within the insulation due to the elevated pressures and local axial pressure gradients thus decreasing their effectiveness. Consequently gas movements, e. g. natural or forced convection, must be excluded or reduced in any Gase by means of flow barriers within the insulation. By these means the flow resistance inside the thermal barriers will be increased. In case of rapid depressurization, however, the flow barriers must not hinder the gas to escape easily from the interior. Otherwise the inner parts of the insulation could be damaged by over-pressures. Therefore breather holes are provided. Their diameters must be optimized with respect to the depressurization rates. In the following at first the requirements for duct insulations and some designs will be described. After that test facilities and experimental results including thermal fluxes, effective thermal conductivities, temperatures and pressure loadings will be intensively discussed. As far as available in literature also thermal barriers for pressure vessels and ducts of reactors in Great Britain and France will be described.