A worker takes radiation readings on the window of a bus at the screening point of the Tokyo Electric Power Company's (TEPCO) tsunami-crippled Fukushima Daiichi nuclear power plant in Fukushima prefecture in this June 12, 2013 file photo. Since March
A worker takes radiation readings on the window of a bus at the screening point of the Tokyo Electric Power Company's (TEPCO) tsunami-crippled Fukushima Daiichi nuclear power plant in Fukushima prefecture in this June 12, 2013 file photo. Since March 2011, Japan's government has focused on the cost of cleaning up after Fukushima, the worst nuclear accident since Chernobyl. Now, the bill is coming due for another unbudgeted consequence of that disaster - shutting down the nation's 48 remaining nuclear reactors for costly safety reviews that could see many of them mothballed. REUTERS/Toshifumi Kitamura/Pool/Files REUTERS/Toshifumi Kitamura/Poo

A technical malfunction at the crippled Fukushima nuclear power plant in Japan has triggered the release of some 240 tonnes of radioactive groundwater into a wrong part of the facility.

Citing Tokyo Electric Power Co (TEPCO), Japan's Kyodo News agency said the misplaced groundwater has an extremely high level of radionuclides, which has reached 37 million becquerels per liter of accumulated Cesium. The safe limit should only be at 25 becquerels or lower.

The contaminated water have flooded the basements of buildings on the plant site, TEPCO said. It assured the public the contaminated radioactive groundwater has no means to leak out of the flooded basements to reach the ocean or leak out to any other areas. The Nuclear Regulation Authority nonetheless ordered TEPCO to strictly monitor the situation and collect the leakage the soonest time possible.

The technical malfunction moved groundwater back into the submerged portion of the plant. Four pumps that should not have been used were operating when workers discovered them on April 12. "Those pumps are normally used to reverse the flow of water or to send the water to other destinations when problems arise in pumping the water to the original destination," The Asahi Shimbun reported.

Some was also pumped into a waste disposal room.

Damaged by an earthquake and tsunami in 2011, the Fukushima Daiichi nuclear plant and Tepco have faced multiple problems, including leaks and power cuts. Tepco has been widely slammed for its extremely poor management.

The Fukushima catastrophe had leaked radiation into the atmosphere, soil and seawater from three of the plant's damaged reactors.