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In February 2017, the World Economic Forum's Futurism column reported on a lecture given by University of Bristol materials engineering professor Tom Scott. As part of the university's Cabot Institute's annual Ideas to Change the World lecture series, Scott spoke in generally theoretical terms about the potential to turn a specific part of nuclear waste into a radioactive diamond which could then be used as a source of energy. In this talk, titled Diamonds Are Forever, Scott spoke optimistically about the prospect of solving two problems at once: The buildup of undisposable radioactive graphite used in containers that store spent nuclear fuel, and the need for a long-lasting source of constant energy. The solution could lie in deliberately radioactive diamonds made from carbon found and extracted from the this graphite casing, as described in Scott’s lecture: Diamonds, by their nature, are made up entirely of carbon, and take hundreds of thousands to millions of years to form naturally. That means that they would never naturally contain any of this radioactive carbon, which has a half life of more than 5,000 years. The prospect of radioactive diamonds, however, raises interesting possibilities for energy generation. That is because carbon-14 emits beta radiation, which in this case simply means it that it puts out high-energy electrons as it decays. Since the 1970s, beta radiation (which does not travel far through air and is therefore relatively safe compared to other forms of radiation) has been investigated as a possible source of energy through the production of what are known as betavoltaic cells. A 1973 paper described the topic as follows: In other words, as individual carbon atoms making up the diamond matrix lose electrons, certain regions with missing electrons (electron holes) would carry a net positive charge than surrounding areas. One could theoretically exploit this to maintain a current of electricity that lasts as long as the carbon-14 is decaying — a process that would take many thousands of years. The specific concept of a diamond battery exploiting these process is, for the most part, theoretical. The concept's individual components — synthetic diamonds and betavoltaic cells — are already a reality, however. Betavoltaic cells which utilized the radioactive elements promethium or plutonium were once a common energy source for pacemakers, prior to the advent of lithium-ion batteries. Today, many betavoltaic systems are employed in applications where a constant supply of low power energy that can also withstand harsh environments are beneficial, according to a 2014 review of the technology: Synthetic diamonds have been a reality for some time as well, and are increasingly common. In his lecture, Scott says: We can grow diamonds, and we do that every day of the week. That process, known as chemical vapor deposition, occurs at high temperatures but (unlike real diamond formation) at low pressure. The process has become increasingly refined and perfected over the years, per a 2009 review on the topic: The benefit to using a diamond (which is, by definition, made up of carbon atoms) to create a betavoltaic cell is threefold. First, it is the hardest material on the planet, and as such will not break apart as its decay continues (or through any other physical mechanism). Second, diamonds are superconductors that readily carry a current. And third, according to Scott, their diamond-making process makes it possible to encase the radioactive carbon-14 diamond with a thin layer of regular diamond made from carbon-12, thus confining its radiation and amplifying its output: A final benefit would be that, in theory, the removal of large amounts of carbon-14 from the graphite in these holding containers would make disposing of that material much cheaper. This idea, as neat and as flashy as it sounds, is, as best we can tell, still entirely theoretical. At the time of his lecture, Scott said they have developed a prototype battery, but this was made using nickel-63 as the radiation source and is therefore not a diamond, and also was not harvested from nuclear waste. Since then, Scott tells us, he and his team have created a prototype synthetic diamond that uses a combination of carbon-14 and bits of tritium (a form of radioactive hydrogen) as the source of beta-radiation. Some devices will have just 14C and others will have tritium and beryllium as additional beta emitting radioisotopes, he told us via email. So far their work has remained private, however. We have filed patents in the US and the UK and a number of publications and demonstrations will shortly be forthcoming. It also bears mentioning that, while the total output of energy from this theoretical battery would far exceed the length of time that modern agriculture has thus far existed, it would likely have fairly limited applications, according to the researcher’s press release: The science discussed in Scott’s Diamonds Are Forever lecture is valid, and rests on decades of research into both betavoltaic systems and synthetic diamond production. However, as such a battery has yet to be made, and because its applications would in all likelihood be somewhat limited, we rank any claim that suggests this technology is a reality now as a mixture.
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