Physicochemical modeling and analysis of the interaction between a core melt of the nuclear reactor and a sacrificial material

Abstract

The problems regarding the design of a new class of materials, namely, sacrificial materials for use in devices intended for localization of a core melt of the nuclear reactor, are considered. Criteria are proposed for the proper choice of the chemical composition of a sacrificial material, as well as of the composition and microstructure of its constituents. The possible alternatives are outlined and analyzed. The results of designing a variant of the composition of sacrificial materials are presented. The experimental data on the interaction of an oxide sacrificial material with simulators of the metal and oxide phases of the core melt are discussed. A new type of combustion of materials, namely, the liquid-phase combustion, is revealed. It is demonstrated that the material designed can be used in systems intended for localization of a core melt of the nuclear reactor.

Physicochemical simulation of the combustion of materials with the total endothermal effect

“…2), which prevents further interaction between the components, the contact of the component C with the phase B results in the formation of the low-melting compound B n C m , which passes into the melt and virtually does not hinder further interaction between the components B and C . In the cases where the reaction (2) is exothermal and proceeds rapidly while the component A rather slowly passes into the melt according to the eutectic mechanism with an endothermal effect, in the zone of the chemical interaction (Fig. 3a, zone II ) there can arises a local increase in the temperature, which results in the interaction of the melt with the material in the combustion regime.…”

“…Therefore, the performed analysis of the above processes indicates that the range of conditions ensuring the possibility of occurring the combustion process with the total endothermal effect is substantially wider than that considered in [1][2][3].…”

“…In the specific case i = 1, the number of products can be equal to unity, as is the case with reaction (2).…”

“…In our earlier works [1][2][3], we analyzed a special case of the interaction between oxide materials and melts with a high reducing power. The study of this process has been of considerable practical interest for the development of so-called sacrificial materials used in the passive safety system of nuclear reactors [4,5].…”

Eutectic crystallization in the FeO1.5–UO2+x–ZrO2 system

“…The data on solidus and liquidus surfaces location in the FeO 1.5 -UO 2+x -ZrO 2 system (mainly at the eutectic temperature) are important for the description of invessel corium melt behaviour and ex-vessel melt retention and crystallization in a core catcher [4,5]. The phase diagram of the ternary system is not yet fully determined and only limited data are available in the past literature [6].…”