Steam oxidation of a steel-5% Boron Carbide liquid mixture
Titre du congrès :ICONE 15th International Conference on Nuclear Engineering
Ville du congrès :Nagoya
Date du congrès :22/04/2007
Boron carbide (B4C) is used in many nuclear reactors Worldwide to control the yield of the nuclear reaction. It is présent as control rods in some of the pressurised water reactors (PWR) and as control blades in boiling water reactors (BWR). In the highly improbable event of a nuclear reactor severe accident leading to core melt, the B4C reacts with steel structures when the température rises during the early phases of the accident, forming a mix that melts and interacts with neighbouring core structures. This mix may therefore play a déterminant rôle in the accident progression.
The présent study provides results on the isothermal oxidation of B4C-steel liquid mixtures exposed to steam. The resulting gas release and the complex microstructure of the B4C-steel oxidised melts after cooling hâve been measured. A caméra was used to record the melt behaviour during reaction.
RcailK sVinw pri-f^rentiiii R .ind Cr oxidation. the formation of bubbles, of melt splash and finally of a protective crust in steel-B4C samples submitted to steam. Hydrogen and to a lesser extent CO and CO2 are produced by the reaction. Main oxidation mechanisms have been identified improving the understanding of steel-B4C mix behaviour in conditions relevant to severe nuclear reactor accident.