Russia's Siberian Chemical Combine (SCC) has fabricated experimental fuel rods with REMIX fuel at its chemical metallurgical plant, the company said. The REMIX (regenerated mixture) fuel was developed by the VG Khlopin Radium Institute in St Petersburg for Techsnadexport (Tenex), the nuclear materials trading arm of state nuclear corporation Rosatom.
REMIX fuel is produced directly from a non-separated mix of recycled uranium and plutonium from reprocessing used fuel, with a low-enriched uranium (LEU, up to 17% U-235) make-up comprising about 20% of the mix. This gives fuel initially with about 1% Pu-239 and 4% U-235 which can sustain burn-up of 50 GWd/t over four years. The used REMIX fuel is then reprocessed and recycled again, after low-enriched uranium top up. The wastes (fission products and minor actinides) are vitrified, as today from reprocessing for MOX, and stored for geological disposal. REMIX-fuel can be repeatedly recycled with 100% core load in current VVER-1000 reactors, and correspondingly reprocessed many times - up to five times according to Tenex, so that with less than three fuel loads in circulation a reactor could run for 60 years using the same fuel, with LEU recharge and waste removal on each cycle.
The SCC's chemical metallurgical plant has installed contact butt welding machines to make the fuel rods. The machines ensure required radiation safety level for the working personnel and plant's infrastructure. "During the acceptance tests, the fuel rods were checked for leak-tightness. Also, non-destructive examination of the weld, position of the fuel column and components inside a fuel rod, as well as destructive testing for helium content inside the fuel rods, were carried out, an SCC's statement said. Evgeny Lachkanov, head of a project at SCC to develop experimental and industrial pilot production of dense fuel, said REMIX technology will enable Russia to achieve a closed nuclear fuel cycle and minimise the volume of radioactive waste it produces.