Six workers at Japan’s crippled Fukushima Dai-ichi nuclear power plant were exposed to a leak of highly radioactive water yesterday, the latest in a string of mishaps the country’s nuclear watchdog has attributed to carelessness, saying they could have been avoided.
Plant operator Tokyo Electric Power Co (TEPCO) has been battling to contain radioactive water at the facility, which suffered triple meltdowns and hydrogen explosions following a devastating earthquake and ensuing tsunami in March 2011.
In the latest incident, a worker mistakenly detached a pipe connected to a treatment system to remove salt from the hundreds of tonnes of water TEPCO pumps over the melted fuel in wrecked reactors at Fukushima to keep them cool.
“It is serious in that it was another problem caused by carelessness, but I do not believe it is a seriously troubling dosage,” Japanese Nuclear Regulation Authority chairman Shunichi Tanaka said. “But the fact that there has been a string of incidents occurring on a daily basis that could have been avoided — I think that is the large problem.”
Tanaka urged TEPCO to improve its handling of contaminated water, but stopped short of saying if it faced any penalties.
The accidents at the Fukushima plant, 220km north of Tokyo, are adding to a crisis no one seems to know how to contain and stirring doubt over TEPCO’s abilities to carry out a complex cleanup widely expected to take decades.
Last week, the regulator ordered TEPCO to draft in additional workers and report within a week on its measures to tackle the hazardous clean-up.
TEPCO said 7 tonnes of water were spilled in yesterday’s incident at the treatment facility, but were contained within the site, adding that the leaked water had an all-beta radiation level of 34 million becquerels per liter.
Tanaka said the leaked water had already been treated to remove cesium, which emits strong gamma radiation harmful to humans.
On Monday, TEPCO said a plant worker accidentally halted power to pumps used to cool the damaged reactors. A backup system kicked in immediately, but the event was another reminder of the precarious situation at the plant.
Last week, TEPCO said 430 liters of contaminated water had spilled out of a storage tank at Fukushima and probably flowed to the ocean.
Japan’s nuclear regulator said yesterday that incident was equivalent to “Level 0” on the International Nuclear and Radiological Events Scale, but gave no official rating.