Fukushima groundwater being released into Pacific

The operator of Japan's destroyed Fukushima nuclear plant began releasing groundwater that it said is within legal radiation safety limits into the Pacific Ocean on Wednesday, in a bid to manage huge amounts of radioactive water built up at the site.

Tokyo Electric Power, or Tepco, has been fighting a daily battle against contaminated water since the Fukushima nuclear station was wrecked by a massive earthquake and tsunami in March 2011.

The controversial release, which was agreed to by local fishermen after extended talks, coincides with a breakdown of a water treatment system for the highly contaminated water held in makeshift tanks.

It also comes amid revelations this week in the Asahi Shimbun newspaper that the majority of workers at the plant fled during the height of the meltdowns after the quake and tsunami knocked out cooling and backup power.

Groundwater flows down from nearby hills and 400 metric tons enter basements of the wrecked reactor buildings each day, Tepco estimates, mixing with highly radioactive water used to cool reactors.

Workers then pump out the contaminated water, treat it and store it in more than 1,000 makeshift tanks that cover the facility grounds. The tanks that hold the most contaminated liquids are nearly full and workers are rushing to build more capacity.

Tepco said 560 tons of groundwater captured and stored before it entered the basements is to be released on Wednesday, using a bypass system that funnels it toward the sea after checking for radiation levels.

Using the bypass, Tepco hopes to divert on average 100 tons of untainted groundwater a day into the ocean.

A water treatment facility known as the Advanced Liquid Processing System, designed to remove the most dangerous nuclear particles, was completely shut down again this week. The system has not been fully operational since it was installed nearly two years ago.

The manager of the plant has admitted the repeated leaks and equipment malfunctions are "embarrassing."

About 90 percent of Tepco workers defied orders and left the Fukushima Daiichi plant on March 15, 2011, after an explosion rocked the site, the Asahi reported on Tuesday, citing unreleased transcripts of interviews with the manager at the time, Masao Yoshida.

Yoshida, widely viewed as a national hero for taking decisive action in the critical days and weeks of the disaster that prevented a more serious crisis, died of cancer last year.