Japan prepares to release treated water from Fukushima nuclear plant

Preparations were underway Wednesday at the wrecked Fukushima Daiichi nuclear power plant in Japan for beginning the discharge of treated radioactive water into the sea the following day.

The plant’s operator, Tokyo Electric Power Company Holdings Inc., measured the concentration level of tritium in the treated water, which is diluted with seawater to ensure it is below one-40th of what is permitted under Japanese safety standards, before discharging it via an underwater tunnel 1 kilometer from the complex.

The Japanese government announced Tuesday that the discharge would begin on Thursday if...