The Tokyo Electric Power Co. said the radiated water leaked for 41 hours beginning May 10 from the No. 3 reactor at the site, where four of six reactors were damaged in the magnitude-9 earthquake and ensuing tsunami, Kyodo News reported.
At a Sunday news conference in Tokyo, utility spokesman Junichi Matsumoto told reporters Tepco has drafted plans to install a water-circulation system to cool the spent-fuel pools at the plant by the end of July, The Wall Street Journal reported.
Since the disaster, officials have scrambled to prevent the radioactive cores from overheating and releasing catastrophic radiation clouds. As of Sunday, part of the stop-gap measures still involved the use of fire hoses to pump water into the reactors, the Journal said.
Matsumoto acknowledged radioactive vapor can still be seen "depending on the weather and wind direction of the day," the Journal said.