A team of scientists led by the UK’s National Nuclear Laboratory, working in partnership with the University of Leicester, have extracted americium from plutonium and used the heat to generate enough electric current to light up a small lightbulb.

NNL said the breakthrough highlights potential for use of americium in radioisotope power systems for missions heading into deep space or to  planet surfaces where other power sources, such as solar panels cannot function. Americium, hitherto considered a waste product of nuclear power generation, is  produced by the radioactive decay of plutonium.

The technical programme underpinning this achievement has been running for several years, supported by funding from the UK government’s Business, Energy and Industrial Strategy (BEIS) department through the UK Space Agency and its ongoing participation in European Space Agency (ESA) programmes.  Contributions also came from European Thermodynamics Ltd, who helped develop the thermoelectric generator unit, and the UK's Nuclear Decommissioning Authority, who permitted the use of plutonium from the UK stockpile.

The purpose of the Space Batteries project, which took two years and cost £1 million, was to determine the technical feasibility and cost of separating americium from plutonium.

NNL split this work into two phases. Phase 1 developed the chemical flowsheet required to process plutonium to produce americium, and carried out the design and costing of the plant that could deliver this on the scale required by ESA. Phase 2 of the project was to prove the process using NNL’s state of the art facilities at its Central Laboratory, Cumbria. A small quantity of plutonium was imported from the stocks held in storage at Sellafield on behalf of the UK government. Alongside these two phases of work, studies were also conducted to examine the security, safety and environmental impacts expected for the final plant. Dialogue was also undertaken to ensure stakeholders were aware of the work and supported further development.

“Seeing this lightbulb lit is the culmination of a huge amount of specialist technical work carried out by the teams from NNL and Leicester, working in collaboration with other organisations such as ESA and UK Space Agency,” said Tim Tinsley, NNL’s Account Director for the work. “Leicester University’s capability in development of the radioisotope power systems was complimented by NNL’s expertise in handling and processing americium in our unique lab facilities. It is great to think that americium can be used in this way, recycling something that is a waste from one industry into a significant asset in another.”