Amplicon Sequencing Reveals Microbiological Signatures in Spent Nuclear Fuel Storage Basins

Area of Science:

• Environmental science
• Microbiology
• Materials science

Background:

• Water quality is critical for the integrity of spent nuclear fuel (SNF) during wet storage.
• Formation of white flocculent precipitates in an SNF storage basin prompted detailed investigation.

Purpose of the Study:

• To characterize the chemical and microbial properties of precipitates in an SNF storage basin.
• To identify unique microbial signatures associated with SNF storage environments.
• To assess the potential for developing bio-indicators for water quality management.

Main Methods:

• Spectroscopic and chemical analyses of precipitate samples.
• Environmental DNA extraction and 454 pyrosequencing of bacterial 16S rRNA genes.
• Comparative analysis of microbial communities in natural and engineered aquatic ecosystems.

Main Results:

• Precipitates were primarily amorphous to crystalline aluminum (oxy) hydroxides with minor Fe, Si, Ti, and U.
• High levels of organic carbon were found co-localized with precipitates.
• Bacterial densities varied significantly; associated diversity exceeded 4,000 OTUs, dominated by Burkholderiaceae, Nitrospiraceae, Hyphomicrobiaceae, and Comamonadaceae.
• Unique microbial community and taxonomic signatures were identified in the SNF storage basin.

Conclusions:

• Episodic changes in basin conditions likely drive aluminum (oxy) hydroxide polymerization, creating microhabitats for bacterial growth.
• The identified microbial signatures are specific to the SNF storage basin environment.
• These findings support the development of novel bio-indicators for SNF facility water quality monitoring and management.