Nuclear power is one of the most cost-effective and productive sources of energy. Nuclear power plants contribute significantly to global electricity production. A factor preventing their further expansion is their overall safety. The operation of nuclear facilities involves the continuous supply of electricity, which is the reason for their vulnerability. Intensive research is being carried out around the world to achieve the required security. Recently, the use of passive safety systems, which operate without the supply of energy through the shaft of a hydraulic machine, has been increasingly discussed. A natural circulation system, also known as thermosiphon or natural convection cooling, consists of a heat source, a condenser and pipework which together form a closed circuit (loop) with a continuously circulating fluid. The circulation itself starts automatically due to the density difference between the hotter and cooler parts of the loop - no additional driving machinery is required while the heat source and cooler are present. The helium loop experimental setup has been created as a model of a real system that is planned to be implemented in nuclear power plants. Its main objective is to investigate the helium flow characteristics under different conditions. It consists of two basic parts, the model of GFR (gas- cooled fast reactor) and the model of DHR (decay heat removal), which are connected by two piping branches. The system dissipates heat in a stable steady state, the analysis of which is the focus of this paper.
Knížat et al. (Fri,) studied this question.