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.
Investigation results on energy effects at corium simulators/sodium thermal interaction suggest high enough energy release as in the form of sodium phase expansion mechanical work, so due to sodium corium relocation. Experimentally estimated duration of thermal interaction active stage equals 5—10 ms, which corresponds to time history characteristic of large-scale interaction. One of the most plausible mechanisms for observed phenomena explanation could be related to sodium thermal inter-action with iron metallic phase, formed due to separation of initial melt onto metallic and ceramic phases. Iron melt temperature is essentially higher than melt point temperature. Temperature condi-tions at metallic phase-sodium boundary satisfy requirements of sodium spontaneous evaporation while contact temperature exceeds spontaneous nucleation temperature in the system “Fe—Na”. As applied to severe accidents scenarios, e.g. ULOF type, iron melt simulated steal melt. It could be suggested that phase separation phenomenon will take place as well in the system “UO2-steel melt”. One could expect the identical thermal interaction mechanism at least for the part of metallic dispersed phase, for which satisfactory wetting is possible during initial contact. Thermal interaction energy release should be accounted for as for severe accidents initial stages, so in the course of the accidents development, e.g. at analysis of the processes occurring in corium traps, where thermal interaction between steel melt and sodium are quite plausible. In the report, hypothetical mechanism of large-scale thermal interaction is considered going out of phase separation phenomenon, observed in the system "Al2O3—Fe".
sodium, corium, simulators, melt, severe accidents, thermal interaction, energy effects, homogenous nucleation, contact temperature, phase separation
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