The second-stage hydroaccumulator system GE-2 for passive heat removal from VVER core and the thermal-hydraulic substantiation of its serviceability

The fundamental difference in the safety assurance of the operating NPPs and those under design implies that the safety in the existing NPPs is achieved by energy-dependent (active) systems and depends on the proficiency of attending personnel. To assure safety, the physical processes proceeding in the facility without power supply are used in new NPP designs; and they are unaffected by human errors. As to the safety level, the design of the new generation nuclear power plant NPP-92 relates to the class of advanced NPPs; and it applies a principle of diversity in the structure of systems responsible for critical safety functions. The passive systems prevent the progression of design accidents into severe ones accompanied by beyond-the-design core damage, provide the localizing properties of containment, and confine the amount of radioactive waste release from NPP. The paper presents the description of the large scale test facility GE-2 constructed by the Lejpunskij Institute for Physics and Power Engineering, the results of experiments, the description of the MASTER-Σ' computer code designed to support and analyze experiments conducted on the test facility. (author)