Biogenic metal phosphates: Low cost, high capacity, stable 'lockups' for the removal of radionuclides from groundwater and decontamination solutions

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The development of nuclear weapons and energy programmes since the 1940s have created a legacy of nuclear waste and contamination worldwide. In 2012, Sellafield Limited (named as the most hazardous nuclear site in the UK) hit the national press/media when a report by the National Audit Office highlighted the considerable challenges and spiralling costs faced by the UKs Nuclear Decommissioning Authority in taking forward the cleanup of this site. In 2012, the Fukushima Daiichi power plant and surrounding contaminated area (650 km2) also recently hit international news headlines when Tokyo Electric Power Company confirmed the accidental release of 300 tonnes of highly radioactive and concentrated waste water into the Pacific Ocean. An ice wall costing £300m has been pledged to prevent groundwater flow through the most contaminated reactor site but there are still plumes of contaminated groundwater that need to be treated and the decontamination of soil (estimated at 60 Mt) will produce even more complex liquid waste.British Nuclear Fuels invested in 30 years supply of naturally occurring zeolites (clinoptilolite) to remove aqueous Cs+ and Sr2+ from fuel cooling ponds. However, legacy and accidental waste is more complex (e.g. saline wastewater, complex and high organic soil decontamination solutions from Fukushima; and lower radionuclides concentrations and high background competing ions in Sellafield groundwater). Zeolites are inefficient under these conditions (e.g. lower sorption capacity and/or low mechanical strength), therefore, new innovative technologies are required for the safe remediation (cleanup) and entrapment (lockup) of radionuclides from these complex contaminated waters.Under complex chemical conditions, microbially-generated, rapidly produced biominerals have high metal adsorption capacity/functionality compared to natural zeolites and commercially available/laboratory grade materials, arising from their unique morphology and nanoscale properties. For example, biogenic hydroxyapatite materials (HA mass more than ten times the mass of the bacteria that produced it) have durable radionuclide adsorption capacity (up to 30 %wt for radionuclides tested: Actinides (U, Am), Sr and Co under simulated groundwater conditions, against high concentrations of competing ions (0.1-2000 mmol/L Na+, Cl-, Ca2+, Mg2+) and at wide ranging pH conditions (3-9.5); the specific nanostructured morphology of Bio-HA was shown to underlie these advantages. Bio-HA also has proven superior stability against metal remobilisation, economics, & function as compared to commercially available materials and, being biogenic will never run out or require procurement or import from other countries (enabling stable-supply and rapid-response). Additionally we have produced a new Bio-CeP material that shows great promise for Cs remediation. However, both biominerals have not been tested or applied as a permeable reactive barrier or ion exchange technology using environmental conditions found at contaminated sites.The grant will be held at the University of Birmingham, which has an established track record in nuclear research dating back to 1950s, (specifically, nowadays, in remediation, decommissioning, health monitoring and residual life prediction for existing nuclear power stations) and recently led a Policy Commission into the future of nuclear energy in the UK. The grant will also be supported by the National Nuclear Laboratory and the Japanese Atomic Energy Authority enabling the achievement of technology readiness level four, rapid worldwide dissemination of research outcomes and increased societal impact.