Undersea tunnel planned to release treated water

NHK -- Aug 25
NHK has learned that Japan's government and the operator of the crippled Fukushima Daiichi nuclear power plant plan to release treated water from the facility into the ocean through an undersea tunnel.

The government officially decided in April that the treated water will be diluted to well below national standards and will then be released into the sea beginning in about two years' time.

The government and the Tokyo Electric Power Company have since been studying two methods. One is to dig a tunnel under the sea to release the water about one kilometer off the coast. The other is to discharge the water directly from the coastline.

Sources told NHK that the government and TEPCO are now planning to create a tunnel so that the water would better diffuse into the ocean.

The sources say TEPCO is set to start a magnetic survey of the seabed as early as next month before conducting a boring survey of geological features.

The company is to work to complete the tunnel by early 2023. It aims to submit the plan to the Nuclear Regulation Authority as early as next month for screening.

There is strong opposition to the plan to release treated water into the environment, mainly from local fishermen.

The government and TEPCO are hoping the tunnel can minimize reputational damage that could affect the local fishing industry.

Water is used to cool molten nuclear fuel at the plant. It mixes with rain and groundwater seeping into damaged reactor buildings.

The water undergoes a treatment process that removes most radioactive material, but it still contains tritium.