Isolation and characterization of culturable bacteria present in the spent nuclear fuel pool water

A spent nuclear fuel (SNF) pool is a key facility for safe management of nuclear waste, where spent nuclear fuel rods are stored in a water pool. The spent fuel rods carry a significant amount of radioactivity; they are either recycled or stored for further processing. Pool water acts as a heat sink as well as a shield against the radiation present in spent/burned fuel rods. The water used in these pools is filtered by an ultra-filtration process which makes certain the purity of water. As the life span of these pools is approximately 20 to 40 years, the maintenance of pure water is a big challenge. A number of researchers have shown the presence of bacterial communities in this ultrapure water. The bacterial types present in SNF pool water is of increasing interest for their potential bioremediation applications for radioactive waste. The present study showed the isolation of six bacterial species in the SNF pool water samples, which had significant radio-tolerance (D10 value 248 Gy to 2 kGy) and also biofilm-forming capabilities. These strains were also investigated for their heavy metal removal capacity. Maximum biofilm-mediated heavy metal (Co and Ni) removal (up to 3.8 μg/mg of biomass) was observed by three isolates (FPB1, FPB4, and FPB6). The ability of these bacterial isolates to survive in radioactive environments can be of great interest for remediation of radioactive contaminants.