Safety of low-power reactor facilities for nuclear power plants

Low-power nuclear power plants are designed to guarantee the electricity and heat supply to economic complexes located mainly in remote regions of the far north of the USSR to which access is difficult. The severe climate, the isolation, difficulty of access and a number of other characteristics of these regions mean that the low-power nuclear plants have to meet a number of specific requirements, including reliability and safety of the reactor units. In the process of creating the reactor units for low-power plants, it became clear that it is possible to guarantee that these requirements are met by using traditional methods (redundancy, control, automation, etc.) including safety features such as self-regulation, natural coolant convection, and also special design solutions (design of fuel elements, fuel channels, layout of equipment, etc.). These solutions guarantee heat removal from the fuel elements, ensure that the temperature of the fuel elements is low enough in the event of accidents involving rupture of the primary circuit and reduce the likelihood of serious accidents accompanied by the release of significant quantities of radioactive products to the environment. The paper analyses the results of applying this approach to the development of reactor units for low-power plants in the case of three types of reactor: (1) the water-graphite channel-type reactors of the Bilibin nuclear heat and power station with tubular fuel rods and natural coolant circulation; (2) water-cooled water-moderated vessel-type self-regulatory reactors with integral layout and natural coolant circulation of the primary circuit; (3) water-cooled water-moderated pool-type reactors without excess pressure in the primary circuit. (author). 6 refs, 2 figs, 1 tab