Authors & Affiliations
Gribacheva V.A., Kukharchuk O.F., Fokina O.G., Shcherbakov S.I.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
Gribacheva V.A. – Engineer-Researcher.
Kukharchuk O.F. – Head of Department of Applied Physics, Dr. Sci. (Phys. Math.), Associate Professor.
Fokina O.G. – Chief Specialist.
Shcherbakov S.I. – Senior Researcher. Contacts: 1, pl. Bondarenko, Obninsk, Kaluga region, Russia, 249033. Tel: +7nbsp;(484) 399-84-43; e-mail:nbsp;
Abstract
The paper proposes the concept of an autonomous nuclear power plant of low-power (1 MW) with thermal emission energy conversion for remote areas. In order to increase the resource, to exclude radiation damage to the electric generating channels (EGC), the channels are removed from the core and the heat from the core to the channels is transferred using a heat carrier at a high temperature (1500 °C). In this regard, a set of problems arises, the consideration of which is devoted to the work. For the simplicity of the design, an integrated reactor layout with natural circulation of a high-temperature coolant was chosen. The structural materials used are niobium and graphite, the coolant is lithium. Cooling of the EGC anodes (at a temperature of ~300 °C) is carried out by natural circulation of lithium using Field pipes closed to an intermediate tank. The configuration of the core (diameter 585 mm, height 600 mm) with a side reflector (graphite 200 mm thick) and rotary controls is justified. Fuel rods with a diameter of 13 mm, carbonitride uranium-zirconium fuel with an equipment of 19.75 % at 235U, loading 1,088 tons, campaign 10 years. It is proposed to cool the reactor using high-temperature air heat exchangers (T > 250 °C). This approach makes it possible to significantly reduce the weight and size parameters of nuclear power plants without reducing the efficiency of energy conversion into EGC. The lithium circuit of the natural circulation of air heat exchangers includes the space of the intermediate tank of the cooling system of the Field pipes. To protect the environment, thermal insulation of the reactor with a layer of sand (ZrO2) is proposed. The thermal insulation is additionally cooled by natural air circulation through a pipe system placed in the volume. Numerical calculation studies have shown the possibility of natural circulation with an insignificant temperature difference in the heat transfer circuit from reactor core to the EGC inside the reactor tank, in the heat transfer circuits from the EGC collectors to air heat exchangers and in the thermal insulation air cooling circuits. Cooling of air heat exchangers is carried out forcibly with the help of fans, air consumption ~5 m3/s. The geometry of the equipment elements has been optimized in order to reduce the size of the installation. The dimensions of the reactor tank are – diameter 1.1 m, height 2 m, volume of heat exchangers 3 m3, overall height 11 m. A pit with a diameter of 7 m and a depth of 10–15 m is required to accommodate the NPP. All NPP equipment can be placed underground, except for fans, hot air outlet pipes.
Keywords
low-power NPP, high-temperature nuclear reactor, lithium, thermal emission conversion, electric generating channel, thermal insulation from the ground, air heat exchanger, numerical calculations
Article Text (PDF, in Russian)
UDC 621.039.534
Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2022, no. 3, 3:9