Nuclear waste disposal is a complex issue in dire need of a solid and reliable solution. Our current and most trusted method – burying very large volumes deep underground in geological disposal facilities (GDFs) – is riddled with problems.
One such problem with this disposal strategy is that, according to researchers at the University of Manchester, “the chemical and biological processes in and around this facility remain poorly understood, and therefore the impact of this facility on its surrounding environment remains uncertain.”
Even though waste materials are encased in concrete before its ultimate disposal underground, ground waters will still eventually reach the waste and react with the cement, causing them to become extremely alkaline. This development prompts a series of chemical reactions that eventually drives the breakdown of the “cellulose” based materials within these complicated waste products.
One notable product related to these reactions is called isosaccharinic acid (ISA). It is a great source of concern because it has the ability to react with an assortment of radionuclides – the famously unpredictable and highly toxic elements formed in nuclear power production and make up the radioactive constituent of nuclear waste. If ISA binds to radionuclides, like uranium, the radionuclides then become substantially more soluble, and the likelihood that they will flow out of the geological disposal facilities to surface environments is far greater.
Interestingly, findings recently published in The ISME Journal bring a new possibility to the table: bacteria with both waste-eating characteristics and the ability to survive the alkaline conditions typical of radioactive waste disposal sites have been discovered. These bacteria can also use ISA as a food and energy source under conditions expected in and in the vicinity of intermediate level radioactive waste disposal sites.
One of the researchers, Professor Jonathan Lloyd, said in a news release, “Nuclear waste will remain buried deep underground for many thousands of years so there is plenty of time for the bacteria to become adapted. Our next step will be to see what impact they have on radioactive materials. We expect them to help keep radioactive materials fixed underground through their unusual dietary habits, and their ability to naturally degrade ISA.”