Remix Fuel
Remix Fuel was developed in Russia to make use of Mixed Recycled Uranium and Plutonium from spent nuclear fuel to manufacture fresh fuel suitable for widespread use in Russian reactor designs. Compared to "conventional" MOX-fuel MOX or Mixed Oxide Fuel as deployed in some western European and East Asian nations generally consists of depleted Uranium mixed with between 4% and 7% reactor grade plutonium. Only a few Generation II and about half of Generation III reactor designs are MOX fuel compliant allowing them to use a 100% MOX fuel load with no safety concerns. Nuclear physics background However all moderated reactors using lightly enriched Uranium fuel produce Plutonium in the course of normal operation as Uranium-238 (typically 94% to 97% of the uranium content in lightly enriched uranium) captures neutrons and undergoes successive beta decays until it is transmuted to plutonium-239. This internally produced Plutonium increases in percentage until it is common enough that a growing percentage of Fission reactions within the fuel are actually within the Plutonium generated during the fuel cycle. Approximately half of the Plutonium-239 "bred" during the fuel cycle is fissioned and another 25% is transmuted through additional neutron capture into other Plutonium isotopes, primarily Pu-240.