The ruined Fukushima nuclear plant leaked radioactive water, but none escaped the facility

TOKYO (AP) — Highly radioactive water leaked from a treatment machine at the tsunami-hit Fukushima Daiichi nuclear power plant, but no one was injured and radiation monitoring shows no impact to the outside environment, the utility operator said Thursday.

A plant worker found the leak Wednesday morning during valve checks at a SARRY treatment machine designed to mainly remove cesium and strontium from the contaminated water, the Tokyo Electric Power Company Holdings said. The machine has been idled for maintenance work.

An estimated 5.5 metric tons (6 tons) of radioactive water — enough to fill two ordinary backyard swimming pools — leaked out through an air vent, leaving a pool of water on an iron plate outside and seeping into the soil around it, TEPCO said, but no radioactive water escaped the compound.

The leaked water was 10 times more radioactive than the legally releasable limit, TEPCO said. The pool of water has been wiped off and the contaminated soil is being removed, said TEPCO spokesperson Kenichi Takahara.

It’s not clear when the machine began leaking, but TEPCO said that no problems were detected in an inspection Tuesday.

The leak may have been caused by valves left open while workers flushed the machine with filtered water — a process intended to reduce radiation levels before the maintenance work, Takahara said. TEPCO said that 10 of 16 air valves that should have been closed were left open during the flushing, and the leak stopped when the valves were closed.

Radiation levels around the plant and inside gutters on the compound have showed no increase.

Takahara offered an apology for the leak, and said that TEPCO is committed to fully investigate and take preventive measures. He said the company pledged to