Information about the SM research reactor and its characteristic features and advantages over other research reactors is presented. The reasons for updating the reactor and the optimal method of solving the problem are indicated. The upgrade program preserves the essential structural features of the rector and allows for the insertion of additional irradiation channels in the fuel part of the core by removing some fuel elements. The reactivity loss arising in so doing is compensated by increasing the uranium content in the remaining fuel elements. A new type of fuel element based on materials with reduced harmful absorption of neutrons is being developed to improve further the technical and economic performance of the reactor. The design and the technology of the fuel element have been developed for three implementations, and experimental fuel elements for reactor tests have been fabricated. The fuel elements have been checked for adherence to the requirements. It has been shown that normal operation of the fuel elements is possible with heat flux density at the surface 9-12 MW/m 2 , which meets the initial requirements.The development of new-generation reactor power-generating facilities as well service life extension for operating reactors require reactor tests of materials up to high irradiation doses over a possibly short time interval. Ordinarily, strict requirements are imposed on attainment of prescribed test parameters in irradiation facilities.At the present time, one of the most suitable reactors for performing high-dose tests of materials and components of nuclear facilities is the SM reactor, in which it is possible to irradiate samples of materials and experimental fuel elements with fast neutrons at flux density 2·10 15 sec -1 ·cm -2 in the fuel part of the core in a water medium with the required parameters. Dispersion-type fuel elements with fuel consisting of uranium dioxide + beryllium bronze, which were developed at the All-Russia Research Institute for Inorganic Materials, are used in this reactor [1]. Such fuel elements have proven their serviceability and reliability at neutron flux density with the surface higher than 15 MW/m 2 and uranium burnup to 80% [2].SM fuel elements consist of a rod which has a cross-shaped cross section and spirals around the longitudinal axis. The large ratio of the heat-emitting surface area to the volume of a fuel element makes it possible to remove heat efficiently. Because the spiraling blades of neighboring fuel elements touch at separate points this design permits self-spacing of the fuel elements in a fuel assembly without local overheating during operation in the most stringent regimes. In turn, this makes it possible to eliminate the spacing parts and the hydraulic resistance of the fuel assembly.
