ATWS Analysis for Innovative Lead-Cooled High-Power Fast Reactor with Accident Tolerant Materials of Core

Abstract

The main purpose of the article is to substantiate the safety of a lead-cooled fast reactor of high power. Thermal power of the reactor is about 5600 MW, electric power is about 2400 MW. The design is similar to the BREST-OD-300 project developed at NIKIET JSC. The safety of a high-power reactor is ensured only with the use of innovative core materials (previously the author proposed to use fuel based on micrograins of UN-PuN mononitride and uranium metal nanopowder, a coolant based on lead of thorium ores, fuel element cladding based on EP823 steel with nanopowder of titanium oxide and yttrium, tungsten-coated cladding are used). Research methods are mathematical modeling of the reactor and reactor emergency modes. The most dangerous emergency modes (ATWS – anticipated transients without scram and their combinations, taking into account the non-simultaneous start) are considered. The studies used the codes developed by the author (Dragon-M, FRISS-2D) and the well-known code for precision neutron-physical calculations (MCU). A safe reactor corresponds to the fulfillment of restrictions for a number of functionals characterizing emergency modes. Studies have shown that when using innovative core materials, any combination of emergency modes does not lead to unacceptable releases of radioactive substances outside the Nuclear Power Plant. The results of the study show the possibility of developing reliable, safe, environmentally acceptable nuclear power based on reactors of this type.