Particulars of the Behavior Under Irradiation of Dispersion Fuel Elements with the Uranium Dioxide + Aluminum Alloy Fuel Composition

Abstract

A fuel with the uranium dioxide + aluminum alloy composition was developed for fuel elements to be used in floating power-generating units and small nuclear power plants. Designs, fabrication technologies, and methods of monitoring cermet fuel elements of different standard sizes with an aluminum matrix and cladding comprised of zirconium alloys were developed at the Bochvar All-Russia Research Institute for Inorganic Materials. A complex of pre-reactor and reactor tests and post-reactor studies of fuel elements was conducted; it was shown that cermet fuel elements are promising. The particulars of the behavior under irradiation of fuel elements with the uranium dioxide + aluminum alloy fuel composition were determined. The high priority of developing floating power-generating units and small nuclear power plants is determined by economic expediency and the prospects for their use in regions which are difficult to access. A floating nuclear power plant is an autonomous power-generating object, which is built in a ship-building plant as a nonpowered vessel and then towed by sea or river to its site of operation. The core of such a power plant must meet enhanced requirements in terms of maneuverability, reliability, and safety under normal and emergency conditions. These requirements can be met by using tested ship technologies to design the core. The leading floating power-generating unit Akademik Lomonosov equipped with a KLT-40S reactor plant, a prototype of which is the setup used on operating nuclear-powered ships, will be positioned in Pevek for a practical demonstration of this technology. The fuel elements are being developed by modernizing the fuel elements used in nuclear icebreakers based on tested designs and technologies. One of the main requirements of fuel elements is the use of fuel with enrichment not exceeding 20%. The fuel composition of the fuel elements used in nuclear icebreakers cannot supply the uranium load needed to meet this requirement. The uranium concentration in the fuel composition based on uranium dioxide in an aluminum matrix (cermet fuel) is approximately two times higher, which makes it possible to meet the indicated requirement [1‐4]. Fuel elements with two designs with cermet fuel, cylindrical shape, and cladding made from the zirconium alloy E-110 were developed for the core of the leading floating power-generating unit: a fuel element with a monolithic kernel (monolithic fuel element) and with a kernel having a cavity of prescribed size, which is located at the center of the fuel element and oriented along the longitudinal axis and is intended to compensate for the radiation swelling of the fuel composition.