Control of microbiological processes during long-term storage of radwastes

Safonov, Alexey; Ершов, Б. Г.; Горбунова, О. А.

doi:10.1007/s10512-012-9554-1

Cited by 4 publications

(2 citation statements)

References 1 publication

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“…The microbiology of this field has been extensively studied (Wolfaardt and Korber, 2012;Safonov et al, 2012;Fru and Athar, 2008; Stroes-Gascoyne et al, 2010; Stroes-Gascoyne et al, 2011A, B) and it was concluded that the surface area and compacted bentonite surrounding the used fuel containers are likely to be completely sterile for many hundreds of years due to extreme heat, radiation and desiccation. These may lessen over time, but compaction of bentonite to a dry density of 1.6 g/cm 3 , with a corresponding saturation swelling pressure of >2 MPa and a w of <0.96, limits culturable microbial numbers to background levels in as-received, powdered dry bentonite (Stroes-Gascoyne et al, 2010).…”

Section: ! 5!mentioning

confidence: 99%

The interplay between microbial metabolism and survival at surface-air interfaces : Implications for the Long-Term Storage of Used Nuclear Fuel

Stone¹

2022

Preprint

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The Nuclear Waste Management Organization of Canada was mandated with the safe, long-term containment of the mounting nuclear industry waste (NWMO, 2005). The engineering of a multi-level barrier system in deep geological repositories to prevent radionuclide escape into groundwater involves the multidisciplinary collaboration of physicists, modelers, engineers, policy makers and legislators. This extreme environment is largely inhospitable to life nevertheless microbial ubiquity demands biological attention if we are to approach risk assessment with legislative integrity. Two decades of work driven by an engineer-turnedmicrobiologist (Stroes-Gascoyne et al., 2010) provided extensive data to support highly compacted bentonite clay for microbial suppression during repository saturation. However, interfaces still demand microbiological attention (Wolfaardt and Korber, 2012), and desiccated bentonite interfaces are thus the focus of this research. The foundational work (Chapter 2) developed tools for evaluating microbial activity in saturated and desiccated bentonite. Novel aspects included the evaluation of precipitated sulphides with fluorometry, and the use of closed loop CO2 measurements to assess microbial metabolism at bentonite-air interfaces. These tools were employed (Chapter 3) to measure the influence of relative humidity (RH) on persistent microbial metabolic activity at bentonite-air interfaces, and the influence of metabolic activity on the clay matrix. It was shown that the combination of bentonite interfaces and high RH stimulated the metabolic persistence of microbial communities during desiccation, despite high RH inhibiting the long-term survival of viable communities. A number of hypotheses were built on these observations (Chapter 4). These extended the observation of the interactive influence of high RH and bentonite to another hygroscopic matrix, polyethylene glycol, confirming that hygroscopic interfaces and high RH improve microbial access to water vapor at surface-air interfaces. It was also shown that oligotrophy increases biofilm desiccation-resilience in a desiccation-tolerant species (Arthrobacter), but not a desiccation-sensitive species (Pseudomonas). An appreciation of the microbial ability to harness their matrix for access to water vapor, and the interaction of this metabolic persistence with long-term survival, is applicable in the modeling and engineering of these industrial environments, and is an intriguing picture of the response of these versatile organisms to the vast challenges within which they so remarkably persist.

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Section: ! 5!mentioning

confidence: 99%

The interplay between microbial metabolism and survival at surface-air interfaces : Implications for the Long-Term Storage of Used Nuclear Fuel

Stone¹

2022

Preprint

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“…Penetration of nitrates and other components into the surface and submerged water-bearing aquifers may enhance the microbial processes 20 , 21 . At some plants, the microbial community was stimulated with organic substrates to immobilize uranium and other radionuclides and remove nitrates 22 – 24 .…”

Section: Introductionmentioning

confidence: 99%

Risk of colloidal and pseudo-colloidal transport of actinides in nitrate contaminated groundwater near a radioactive waste repository after bioremediation

Safonov

Lavrinovich

Emel’yanov

et al. 2022

Sci Rep

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The possible role of biogeochemical processes in the transport of colloidal and pseudo-colloidal U, Np, and Pu during bioremediation of radionuclide- and nitrate-contaminated groundwater was investigated. In two laboratory experiments with water samples taken from contaminated aquifers before and post bioremediation, we found that microbial processes could cause clayed, ferruginous, and actinide colloids to coagulate. The main mechanisms are biogenic insoluble ferrous iron species formations (goethite, pyrrhotite, siderite, troilite, and ferrihydrite), the aggregation of clay particles by microbial metabolites, and the immobilization of actinides in the bacterial cells, large polymers, and iron and clayed sediments. This process decreases the risk of colloidal and pseudo-colloidal transport of actinides.

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Biological factors affecting the evolution of safety barrier materials in the Yeniseisky deep geological repository

Abramova

Popova

Artemiev

et al. 2023

Engineering Geology

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Control of microbiological processes during long-term storage of radwastes

Cited by 4 publications

References 1 publication

The interplay between microbial metabolism and survival at surface-air interfaces : Implications for the Long-Term Storage of Used Nuclear Fuel

The interplay between microbial metabolism and survival at surface-air interfaces : Implications for the Long-Term Storage of Used Nuclear Fuel

Risk of colloidal and pseudo-colloidal transport of actinides in nitrate contaminated groundwater near a radioactive waste repository after bioremediation

Biological factors affecting the evolution of safety barrier materials in the Yeniseisky deep geological repository

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