The management of radioactive waste and contaminated water at Japan’s tsunami-crippled Fukushima nuclear plant could be improved, the UN nuclear watchdog said.
The operator of the plant said in February that sensors in its drainage system had detected a leak of contaminated water, which was way beyond radioactive levels already seen on-site and had probably leaked into the sea through a gutter when it rained.
The decommissioning of the Tokyo Electric Power Co (TEPCO) Fukushima reactors hasn’t been plain sailing, as the plant has been plagued by a string of radioactive water errors since an earthquake and the tsunami hit the plant in 2011.
A highly diluted radioactive plume from the original incident made its way to waters off the coast of Northern California last year after two valves were allegedly left open by mistake.
The findings of the International Atomic Energy Agency (IAEA)’s report recorded good progress in cleaning up the site, while also acknowledging that some of the leaks have been dealt with to avoid a repetition of such incidents. Efforts have included filling and covering of gaps, recovery of contaminated soil and treating surfaces to prevent rainwater leakages.
However, “the IAEA experts encourage TEPCO to continue to focus on finding any other sources contaminating the channels,” the agency said.
There was room for improvement of how the newly created branch of TEPCO, Fukushima Daiichi Decontamination and Decommissioning Engineering Company (FDEC), handled the radioactive waste. More complete waste characterisation and packaging was called for.
“FDEC could better employ long-term radioactive waste management principles, beyond the segregation, relocation and dose reduction/shielding currently performed,” the watchdog said.
“While recognising the usefulness of the large number of water treatment systems deployed by TEPCO for decontaminating and thereby ensuring highly radioactive water ... is not inappropriately released..., the IAEA team also notes that currently not all of these systems are operating to their full design capacity and performance.”
The IAEA is expected to collect water samples from the sea near Fukushima to guide Japanese authorities with the decommissioning process.