Problem:

Waste from a nuclear fission generating plant can remain radioactive for 250,000 years.

Solution:

Recycle the nuclear waste for diamond battery power.

A team of physicists and chemists led jointly by Professor Tom Scott and Dr Neil Fox at the University of Bristol have grown a man-made diamond that, when placed in a radioactive field, is able to generate a small electrical current in a nuclear-powered battery.

Unlike the majority of electricity-generation technologies, which use mechanical energy to move a magnet through a coil of wire to generate a current, the man-made diamond is able to produce a charge simply by being placed in close proximity to a radioactive source.

The Bristol team have demonstrated a prototype ‘diamond battery’ using Nickel-63 as the radiation source.

They are now working to significantly improve micropower battery efficiency by utilising carbon-14 incorporated within the diamond battery.

One available source of this radioactive version of carbon, is found in decommissioned nuclear reactors where it is generated in graphite blocks used to moderate the reaction in nuclear power plants.

Extracted from waste at the Berkeley power station in Gloucestershire, Carbon-14 was chosen as a source material because it ​is a pure beta emitter, which is quickly absorbed by any solid material. ​

Carbon 14 is naturally present in the ecosystem at a background level as it is easily taken up by living matter. This would only make it dangerous to ingest or touch with your naked skin if present in unnaturally large quantities, but safely held within a diamond, no short-range radiation can escape.

Neutron irradiated (Magnox) reactor graphite blocks form the bulk of the existing legacy feedstock. Each block contains machined ‘through-hole’ channels for accommodating fuel rods and gas cooling.

The wall surfaces of these channels contain the bulk of the carbon 14 carbon which can be harvested by robots and converted into gas such as carbon dioxide and into methane. Gas centrifuges will be used to purify C14 methane and there are techniques to efficiently separate light  isotopes.

The UK currently holds almost 105,000 tons (95,000 tonnes) of graphite blocks and by extracting carbon-14 from them, their radioactivity decreases, reducing the cost and challenge of safely storing this nuclear waste.

Radioactive material from a nuclear power plant being decommissioned in the U.K. could soon be used to create “ultra-long-lasting” power sources. Using carbon-14 the battery would take 5,730 years to reach 50% power, which is about as long as human civilization has existed.

Neil A. Fox et al., “A theoretical study of substitutional boron-nitrogen clusters in diamond” Journal of Physics Condensed Matter 30(42) · August 2018

Discover solution 30: A battery made from seawater

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