NUCLEAR REACTOR FUEL ELEMENT Russian patent published in 2000 - IPC

FIELD: nuclear power engineering; water-moderated reactors. SUBSTANCE: fuel element has sealed cladding and high-melting metal plug, for example that made of stainless steel X16H15M3 or zirconium alloy such as Zr + 1%Nb, or chromium-nickel alloy (20-50% Cr); heat-conducting matrix made of pore- free potting alloy such as Al + 12%Si or Al + 0.5%Ni, or Al + 0.5%Ni + 0.5%Zr + 0.25%Mo that accommodates fuel pellets of uranium oxide (UO₂ or U₃O₈) of 4-33% porosity, size 200-3000 mcm, volume fraction 61-70%. Matrix has no pores. Fuel-element core is tightly bonded to cladding metal. Mentioned factors ensure at least 20 W/m-deg. heat conductivity of fuel core, low level of core working temperatures (maximum 500 C), steady geometry of fuel element throughout long-time operation, and utmost accumulation of fission fragments. Provision is made for controlling porosity margin in fuel pellets, eliminating swelling in the course of long-time service, reducing working temperatures of fuel core. EFFECT: improved reliability and serviceability of fuel element. 3 cl, 4 dwg