The amount of used nuclear fuel will continue to increase, reaching around 1 million tonnes by 2050. The uranium and plutonium that could be extracted from that used fuel would be sufficient to provide fuel for at least 140 light water reactors of 1 GWe capacity for 60 years, she said. “It makes sense to consider how to turn today’s burden into a valuable resource.”
Rosatom estimates that the current closed fuel cycle – in which reprocessed uranium (RepU) and plutonium are only used once – can at best use about 21% of used light water reactor fuel, with the remaining 79% – mostly uranium-238 – going into storage. The new nuclear fuel cycle could use a further 77%, with only 2% of used fuel then requiring disposal as waste, Zalimskaya said.
Russia is already working to modernise its nuclear fuel cycle and currently has four main processing facilities operating at the back-end. The Mayak reprocessing facility is in the process of upgrading its infrastructure for high-active waste handling, and is reprocessing a broader range of used nuclear fuel starting with VVER-1000 fuel from last year.
The Siberian Chemical Plant, in Seversk, is a production facility operating with RepU. Mining and Chemical Combine, in Zheleznogorsk, is a cluster of used fuel management with centralised interim wet and dry storage facilities, a pilot demonstration centre for reprocessing, to be commissioned in 2019, and a fabrication plant for mixed oxide (MOX) fuel for fast reactors. The National Operator for Radioactive Waste Management, NO RAO, expects to commission in 2022 an underground research laboratory for the deep geological storage of highly active waste.
Zalimskaya presented three possible scenarios for the back-end of the fuel cycle which are currently being tested by Rosatom. The first scenario involves recycling of RepU and plutonium in the existing nuclear power fleet, with RepU used to fuel VVER-1000 reactors and plutonium in the BN-800 fast reactor.
The second scenario is a so-called REMIX nuclear fuel cycle. REMIX fuel is produced directly from a non-separated mix of recycled uranium and plutonium from the reprocessing of used fuel, and can be used in light-water reactors. The used REMIX fuel can be reprocessed and recycled repeatedly.
The third scenario is a two-component nuclear power system involving light water reactors and fast reactors. In this scenario, used fuel from light water reactors is reprocessed with the RepU recycled in the same reactors and the plutonium recycled in MOX fuel in fast reactors. Plutonium separated from used fast reactor fuel is suitable for use in MOX fuel that can then be used in the light water reactors.
All three scenarios have evolved from simple, existing practices, Zalimskaya said, and all are now being tested in practice in Russia.