‘Reprocess To Reuse’ Nuclear Waste Is The Way Forward
A handful of countries including India and Russia have adopted the method of ‘reprocess to reuse’ of spent fuel in ‘closed fuel cycle’ based on innovative fuel refabrication and ‘fast’ reactors.
Undeniably, nuclear is an abundant source of energy with potential to address energy security concerns of the entire humanity for a prolonged period of time; but serious attention is required for the eventual elimination of nuclear waste that are piling up in temporary storages. A global stockpile of around 250,000 tonnes of highly radioactive spent fuel are stored across some 14 countries for disposal. The volume is likely to increase soon as many reactors, especially in Europe, due to be decommissioned by 2025. The idea of geological repositories for long-term burial of nuclear waste, though sounds technically feasible, has been a matter of intense public opposition. A prudent alternative, therefore, is to recycle fuel-worthy material that remains in the ‘spent fuel’.
The ‘spent fuel’ now seems mistakenly called ‘nuclear waste’ and considered a national burden in public opinion; when in fact, they can be a national assetand an additional source of energy through reprocessing and advanced reactor technology. A handful of countries including India and Russia have adopted the method of ‘reprocess to reuse’ of spent fuel in ‘closed fuel cycle’ based on innovative fuel refabrication and ‘fast’ reactors.
Mainly three concerns are highlighted regarding the spent fuel or nuclear waste: 1) increase the volume of waste; 2) long-term radioactivity in high-level waste; and 3) threat of plutonium being diverted. Reprocessing or recycling of the spent fuel can potentially address all these concerns amicably. The method currently used for reprocess is called PUREX (plutonium-uranium extraction) to recover fissile and fertile materials to provide fresh fuel for nuclear power plants. This helps to “recover unused plutonium, along with unused uranium thereby closing the fuel cycle, gaining some 25-30% more energy from the original uranium”.
Many opine that there are real advantages of reprocessing of spent fuel: the amount of material that required for a specific amount of electrical production is reduced by a factor of 10; the cooling-off time of remaining waste material is reduced to around 400 years which otherwise would last many thousand years; and the volume of final waste is also reduced by roughly a factor of 10. Therefore, the final waste generated can be managed relatively easily through the ‘vitrification’ method. The closed fuel cycle also reduces the chances of proliferation or misappropriation of radioactive material.
According to IAEA Nuclear Technology Review 2020, “around 400,000 tonnes of heavy metal have been discharged…as spent nuclear fuel, of which about 30% has been reprocessed. The rest is stored either in reactor pools or in the 151 away-from-reactor spent fuel storage facilities in 27 countries.” Only France, Russia, Japan, UK, and India are reprocessing with combined civil capability of 3860 tonnes of spent fuel per year. The ultimate aim is to eliminate the so-called ‘nuclear waste’ from nuclear power generation. If permanent repository is a pipe dream and temporary storages are risk-prone, reprocessing of spent fuel seems to be a silver lining that the all nuclear-capable countries must readily embark on.
Russia has achieved phenomenal progress in this domain and likely to attain full industrial scale during 2030-40. It is the only country in the world where industrial “fast” neutron reactors are now operating with depleted uranium. As part of the Proryv (Breakthrough) project, Russia has planned to separate minor actinides (neptunium and americium) from radioactive waste and include them in the fuel matrix. The Breakthrough project comprises a fuel fabrication/refabrication module for production of dense nitride fuel for fast reactors; a nuclear power plant with a BREST reactor; and a used fuel retreatment module. After the necessary amendment to domestic legal framework in 2001, Russia has also imported depleted uranium hexafluoride from Germany which in fact are not nuclear waste, but a promising nuclear raw material and source of profit. The depleted uranium is both a potential source of uranium-235, and a source of nuclear fuel for fast reactors, which will be used in closed fuel cycle. Moreover, Russia does not face any acute problem of storage of uranium hexafluoride. Commissioning of the RBMK-1000 “dry” spent nuclear fuel (SNF) storage facility in December 2015 has solved the problem of overfilling of on-site SNF storages, beside solving the problem of unscheduled shutdown of about 50% of the electrical capacity of Russian NPPs. Russia has approximately 22,449 metric tons of spent fuel (2016), much of it stored in temporary cooling pools. Meanwhile, it generates around 700 tonnes of spent fuel from its nuclear power plants, research reactors, and submarines every year. In its effort to eliminate nuclear waste its perspective plan for reprocessing of domestic and imported spent fuel seems promising. According to data from the predecessor of Rosatom, the Russian Ministry of Atomic Energy (Minatom), Russia could earn up to US$20-21 billion out of the reprocessing business in the long-run. This earning in turn will support reprocessing of domestic spent fuel, solve environmental problems, meet future nuclear fuel demand, and reduce proliferation risks.
Currently, Russia has two reprocessing facilities: RT-1 plant (at Mayak) in Chelyabinsk, and RT-2 in Zheleznogorsk which is under construction. With its completion, Russia’s reprocessing capacity would increase to 1,940 tonnes per year. With modernization and improvement in efficiency, the RT-1 facility is planned to function as a universal plant capable of processing all types of spent fuel. Previously, the plant handled used-fuel from VVER-440 reactors, submarines, fast and research reactors. Along with the advancement in nuclear reactor technology, global nuclear discourse is now hinting at a profitable reprocessing market, and Russia should capitalize on this opportunity expeditiously. Given its global dominance in reactor technology and nuclear fuel supply, it can spearhead to create big market for its fourth-generation reactors integrated with closed fuel cycles technology. The recent allocation of 64 billion rubles (almost US$1 billion) for the development of energy components including technologies for closed fuel cycle based on fast reactors is one of the key forward looking tasks for Russian nuclear industry for the period up to 2024.
