Authors & Affiliations
Zagorulko Yu.I., Ganichev N.S.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
Ganichev N.S. – Head of laboratory, A.I. Leypunsky Institute for Physics and Power Engineering.
Objectives and targets of the investigation, presented in the report consisted in study of structural materials wastage at their initial contact with corium simulator melt as well as physical and chemical properties of garnisage layer formed at the boundary of high-temperature melt with relatively “cold” wall. Experiments have been carried-out with melts produced by means of stehiometric thermite reaction Fe2O3+2Al=Al2O3+2Fe. Structural material samples under investigation by their composition corresponded to stainless steel 12X18H10T. The experimental methodology was selected to simulate the totality of processes, controlling corium behavior towards structural materials, including corium-sodium thermal interaction. In the experiments sodium vapor phase, developed in the course of thermal interaction, was simulated by nitrogen, contained in thermite mixture and gas plenum of experimental parts. Going out of the experimental results one could suggest that nitrogen thermal expansion by its effects corresponded to characteristics of corium sodium thermal interaction. Pressure wave, formed due to rapid heating of nitrogen, causes an ejection of the melt out of experimental part vessel. Axial relocation of the melt produced dynamic loads onto disk samples estimated to be equal of ~5·105 Pa. It was shown experimentally, that melt was undervented to phase separation onto metallic and ceramic phases with regards of their densities. Formation of garnisage layer at the melt boundary with initially low-temperature wall has occurred after phase separation time, as its chemical composition corresponded to that of separated phases with a certain small enrichment by chromium and nickel. Material wastage including reaction vessel and deformations took place only for samples affected to impact dynamic loads. Information, obtained in the experiments can be used in scenarios of severe accidents and especially in analysis of corium traps integrity.
corium, simulator, thermite reaction, structural materials, garnisage layer, thermal interaction, dynamic loads, phase separation, corium traps integrity
1. Grigor'ev I.S., Melihov E.Z. Fizicheskie velichiny [Physical quantities]. Moscow, Energoatomizdat Publ., 1991. 1232 p.