Nuclear waste disposal continues to elude scientists; the challenge isn’t only a matter of figuring out where to discard radioactive material but how to extract and recycle valuable substances. Physicists and chemists from the University of Bristol have found a way to convert tons of nuclear waste into human-made diamond batteries that can generate a small electric current for longer than 5,730 years.
The innovative technology was presented on Friday, November 25th at the Cabot Institute’s sold-out annual lecture, “Ideas to change the world.” Unlike other electricity-generating tech solutions, the human-made diamond battery doesn’t move a magnet through a coil of wire to generate current; instead, it produces a charge simply by being placed in proximity to a radioactive source. As a result, the diamond battery lacks moving parts, gives off no emissions, and is maintenance-free.
Tom Scott, Professor in Materials in the University’s Interface Analysis Centre and a member of the Cabot Institute, said: “By encapsulating radioactive material inside diamonds, we turn a long-term problem of nuclear waste into a nuclear-powered battery and a long-term supply of clean energy.”
Tons of potential
With the number of aging first-generation reactors waiting for decommissioning, there is a huge abundance of radioactive materials with battery-forming potential. This notion holds especially true when considering that nuclear waste removal isn’t the top priority, but rather devising a long-term storage strategy that grants continued access to valuable radioactive isotopes needed in industry and medicine or that may have potential energy generation uses.
England’s first-generation reactors contain an abundance of radioactive material ripe for diamond batteries, accumulating over 104,720 tons of radioactive graphite blocks. After decades of exposure, the radioactive graphite blocks surrounding the fuel rods changed some of the inert carbon into radioactive carbon-14, a low-yield beta particle that cannot penetrate beyond a few centimeters of air but is too dangerous to release into the environment. By removing most of the carbon-14 from the graphite blocks, the Bristol team believe they can successfully transform it into electricity-generating diamonds.
How’s it made?
Discovering that carbon-14 wasn’t uniformly distributed in the graphite blocks, the team first heated the blocks to drive out the isotope from the radioactive end. Next, low pressure and high temperature were applied to compress the gas into a human-made diamond. The resulting diamond’s crystal lattice then interacts with the beta particles emitted by the carbon-14, throwing off electrons and generating electricity. Because the diamonds become radioactive, they are given a second non-radioactive diamond coating to function as a radiation shield.
“Carbon-14 was chosen as a source material because it emits a short-range radiation, which is quickly absorbed by any solid material,” says Neil Fox from the School of Chemistry. “This would make it dangerous to ingest or touch with your naked skin, but safely held within the diamond, no short-range radiation can escape. In fact, diamond is the hardest substance known to man; there is nothing we could use that could offer more protection.”
An earlier prototype diamond battery was constructed using the isotope nickel-63, but the team plans on incorporating carbon-14 as it’s significantly more efficient, retaining 50% of its capacity after 5,730 years. Despite their low-power relative to contemporary batteries, the long lifespan of diamond batteries may revolutionize low-power devices like pacemakers, high-altitude drones, and satellites in the long term. Scientists haven’t yet finalized the amount of carbon-14 in each battery, but one battery containing 1 g of carbon-14 delivers about 15 Joules per day.
Source: Newatlas via Bristol University
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