FUEL ELEMENTS OF RESEARCH REACTOR CM

摘要

Reactor "CM" is intended to produce transuranium nuclides and to carry on investigations in a wide range. Original fuel assembly of reactor contained plate fuels that were spaced with vanes and corrugated bands. Nickel was used as a cladding material, fuel meat was produced from UO_2 + electrolytic nickel composition. Fuel plates were replaced by self-spacing cross-shaped dispersion fuels clad in stainless steel with UO_2 + copper-beryllium alloy dispersion composition as its meat. In 2005 the reactor "CM" was updated. The purpose of updating was to increase the quantity of irradiation channels in the reactor core and to improve the neutron balance. The updating was implemented at the expense of 20 % reduction in the quantity of fuel elements in the core which released a space for extra channels and decreased the mass of structural materials in the core. The updated reactor is loaded with modified standard fuel elements with 20 % higher uranium masses. At the same time stainless steel in fuel assembly shrouds was substituted by zirconium alloy. To-day in progress are investigations and work to promote the second stage of reactor updating that involve developments of cross-shaped fuel elements having low neutron absorption matrix materials of meat.