How the Next Generation Nuclear Plant might one day look (Image: Idaho National Laboratory)
The Next Generation Nuclear Plant (NGNP) could be used to burn up plutonium and transuranics currently thought of as waste after recently commissioned research.
The US Department of Energy (DoE) is planning to build a very high temperature gas-cooled reactor (VHTR) at Idaho National Laboratory, with the prime objective of supplying heat at about 900°C. This heat could be used to generate electricity, or for other industrial processes such as hydrogen production or water desalination at a neighbouring facility.
Research commissioned this week by the DoE would see two teams of scientists examine the potential of a VHTR such as NGNP for 'deep-burn' of nuclear fuel. This means using nuclear fuel which contains not just uranium but also plutonium and certain higher transuranic elements which would otherwise be treated as high-level radioactive waste.
The DoE said that transuranic elements are the hottest and most radiotoxic chemical elements in used nuclear fuel, but that they could be recycled into particle-coated fuel and used to produce more energy. It added that 'deep-burn' referred to the VHTRs ability to burn up to 65% of its inital fuel, compared to burn-up levels of around 5% in conventional light-water reactors.
The concept of deep burn relates to the US-led Global Nuclear Energy Partnership (GNEP), in which advanced reactors would destroy similar wastes produced by mainstream light-water reactors of the kinds widely used today. It is projected that volumes of high-level waste could be reduced by a factor of 50, while extra electricity is generated. The reactor envisaged for GNEP, however, would be a sodium-cooled model.
The DoE said that the deep-burn research would go towards the GNEP effort but would also "enable a quantitative assessment of the scope, cost and schedule implications of extending the NGNP mission in the future to destruction of plutonium and other transuranics." This is a remarkable turn-around compared to recent years when NGNP appeared to be effectively on hold and GNEP was promoted. When announcing the research, the DoE noted that the two research efforts would be coordinated to ensure synergism and avoid duplication.
Idaho National Laboratory will conduct the deep-burn research program - worth $6.3 million - while Argonne National Laboratory will do associated research concerned with modelling and simulation of VHTRs at a cost of $1 million. The labs were chosen after a competitive process also open to universities and commercial entities.