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Descripción
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| Previous research carried out at the Cofrentes Nuclear Power Plant (NPP) showed that in the water of the Spent Nuclear Fuel (SNF) pools there are microorganisms which colonize metallic materials immersed in the pools and form biofilms. We observed that these biofilms retain radionuclides, so they could be used to decontaminate radioactive water in a bioremediation process. In order to analyze the effectiveness and the economic viability of this process two bioreactors were designed and installed on-line in the water cooling system of the SNF pools in the fuel building at the Cofrentes NPP. Inside each bioreactor 12 stainless steel balls were located, and were removed periodically for analysis along 22 months. Scanning electron microscopy (SEM) revealed that the stainless steel balls were progressively colonized by filamentous and long rod-shaped bacteria that formed biofilms on their surface. After 15 months corrosion products were observed on the materials; at the end of the study the material was corroded and no microorganisms could be seen on the stainless steel surface. The radioactivity of the biofilms was determined by gamma-spectrometry. We found that the biofilms started to retain radionuclides after 3 months and accumulated them until about 300 days when radioactivity began to decrease. The main radionuclide detected in the biofilms was 60Co. After 22 months radioactivity came back to almost the initial levels, probably due to biofilms detachment as the SEM images demonstrated. The identification of bacteria through molecular techniques such as cloning and sequencing of a discrete fragment of 16S rDNA gene showed that biofilms were formed by a low diversity of nonculturable microorganisms. A total of 502 clones were sequenced, belonging most of them to Gammaproteobacteria, Alphaproteobacteria and Actinobacteria classes. In our opinion metagenomic studies searching for relevant enzymatic activities implicated in the radionuclides retention would be very useful for the enhancement of those activities. Procedures developed by this research are of interest for the decontamination of radioactive waters in the Nuclear Power Industry. | |
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Internacional
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Si |
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Nombre congreso
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COST D33: Nanoscale Electrochemical and Bioprocesses (Corrosion) at Solid-Aqueous Interfaces of Industrial Materials: Final Workshop |
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Tipo de participación
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960 |
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Lugar del congreso
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Cluj-Napoca (Romania) |
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Revisores
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Si |
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ISBN o ISSN
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978-973-1937-09-0 |
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DOI
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Fecha inicio congreso
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13/05/2005 |
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Fecha fin congreso
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15/05/2005 |
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Desde la página
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49 |
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Hasta la página
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49 |
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Título de las actas
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COST D33: Nanoscale Electrochemical and Bioprocesses (Corrosion) at Solid-Aqueous Interfaces of Industrial Materials |