## 2 IAS Structure and Characteristics  
For the development of an IAS, a categorization of data obtained during experiments over a long period of time was conducted. The main criteria for data separation were:  
* The type of melt retention model under study;
* The scale of the model in relation to the mass of the resulting melt. According to the type of model under study, all experiments are divided into experiments with the study of the processes of a melt retention inside of the vessel (accident at the Three Mile Island NPP) and experiments with an out-of-vessel melt retention (accidents at the Chernobyl NPP, Fukushima-1). According to the scale of the model, all the experiments performed can be divided into large-scale and small-scale experiments. This division depends on the amount of material used in the simulation of severe accidents, while large-scale experiments are carried out on the \"ANGARA\" test bench and small-scale experiments are carried out on the \"VCG-135\" test bench. The ANGARA test bench is designed to study the interaction between a nuclear reactor fuel melt and structural materials under conditions simulating an accident with a reactor core melting [9]. At different times, the \"SLAVA\", \"LAVA\", \"LAVA-M\" and \"LAVA-B\" installations were used on the test bench for the experiments. Currently, the Lava-B is one of the most popular installations of the \"ANGARA\" facility. This installation consists of two main elements: an electric melting furnace (EMF) and a melt receiver (MR). Figure 1 shows the view of the Lava-B installation, and the technical characteristics of the EMF and MR are in Tables 1 and 2, respectively. For collecting, the registration and pre-treatment signals from the primary converters and automation devices located on the \"LAVA-B\" test bench itself and the technological systems of the test bench, as well as to implement the functions of logical control of the technological parameters of the test bench systems, a specialized information-measuring system (IMS) of the \"ANGARA\" facility was used. The information and measuring system provides the following main functions: \begin{table}
\begin{tabular}{c c c} \hline \hline \# & **Parameter Name** & **Parameter Value** \\ \hline
1 & Electric melting furnace & \\ \hline
1.1 & Mass of melted burden, kg & to 60 \\ \hline
1.2 & Maximum melt temperature, K & 3300 \\ \hline
1.3 & Melting method & inductive \\ \hline
1.4 & Duration of burden heating and melting, min & to 60 \\ \hline
1.5 & Maximum active power leads up to EMF crucible, kW & to 150 \\ \hline
2 & Melt receiver & \\ \hline
2.1 & Inner diameter of the vessel, mm & 1800 \\ \hline
2.2 & Maximum length of inner cavity, mm & 2510 \\ \hline
2.3 & Wall thickness of the vessel, mm & not less than 30 \\ \hline
2.4 & Vessel mass (without heat insulation) & \(\sim\)8300 \\ \hline
2.5 & Mass of removable lid (without trolley), kg & \(\sim\)2500 \\ \hline  & Work pressure, MPa: & \\
2.6 & - & in a stationary mode; & 4.0 \\  & - & in an impulse mode. & to 5.0 \\ \hline
2.7 & Permissible temperature in MR cavity, \({}^{\circ}\)C & to 200 \\ \hline
2.8 & Temperature of MR wall material, \({}^{\circ}\)C & 50 \\ \hline
2.9 & Number of viewing windows & 4 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Main characteristics of the “LAVA-B” installation. Figure 1: LVA-B installation.