Researchers have found a way to ‘mass’ produce graphene sieves which could vastly reduce the amount of energy used in the production of heavy water for the nuclear industry.
Heavy water is used predominantly as a moderator in nuclear fission reactors.
To make heavy water, deuterium – a heavy isotope of hydrogen – is combined with oxygen. Deuterium occurs naturally in tiny concentrations, but it needs to be isolated in much the same way aluminium needs to be separated from its mineral ore. However, this process is energy intensive and costly. According to Manchester University, the production of 1kg of heavy water consumes enough energy to power an average American household for an entire year.
In the experiment carried out by Manchester University, graphene was used to sieve the heavy isotope from a hydrogen gas feed which naturally contains deuterium. The university said the introduction of the revolutionary material into the process could reduce energy consumption by over one hundred times compared with current technologies.
Last year, the same group of researchers found that graphene could be used in this process, but it said the industrial opportunities of the discovery were not analysed at the time as scalable manufacturing methods for the membranes did not exist.
Now, the Manchester researchers said they had developed fully scalable prototype membranes and demonstrated the isotope separation in pilot scale studies.
Graphene honeycomb lattice
University of Manchester research fellow Sheng Zhang said: “This is a crucial milestone in the path to taking this revolutionary technology to industrial application.
“The potential gains are high enough to justify its introduction even in the highly conservative nuclear industry.”
The team is also looking at ways of using the membranes to sieve tritium – a radioactive isotope of hydrogen.
Manchester University professor of condensed matter physics Sir Andre Geim added: “Tritium discharged both from nuclear power plants and as a result of environmental disasters is a major global concern.
“We believe this technology can economically transform the environmental footprint of future nuclear plants.”