Studies of the Corium Physicoсhemical and Thermophysical Properties

When designing new NPP of enhanced safety as well as planning and realizing operations on corium managing at emergency NPP data are required on corium properties and processes associated with core melt and fuel, materials and nuclear reactor structure behavior in transient and emergency modes.

Studies of the corium physicochemical and thermophysical properties, obtained during simulation experiments, are carried out in the National Nuclear Center of RK. 

Experiments on modelling the processes, occurring with the corium in nuclear reactor during severe accidents, have been conducting at high-temperature simulation experimental bench HFG-135. This is a unique research tool, enabling to heat samples up to 3000 °С.

Tungsten-rhenium thermocouples are used as a main tool for temperature measuring, and pyrometers - for noncontact temperature measuring.

After heating at HFG-135 bench, samples are studied using modern equipment: Enpyrean x-ray diffractometer, optical and scanning electron microscopes, UTFI-2 facility for thermal and physical properties determination.

For the recent 2 years NNC specialists made classification of corium composition and properties, identified factors, determining basic characteristics crucial for safety system tasks solving.

Basing on classification, the methodology has been developed for obtaining the required corium composition. Consolidated melts and data on corium melting temperature of two different compositions were obtained in the process of methodology finding. Methodology to study the consolidated corium characteristics is developed and approved. Computer modeling is made for residual energy release in corium, obtained by induction method.

Currently operations are continued for data obtaining on corium thermophysical, physicochemical and structural properties.