TOKYO — Tokyo Electric Power’s plan to manage radioactive water at its wrecked Fukushima plant may include a controlled discharge into the ocean once its toxicity is brought within legal limits, Japan’s nuclear regulator said Monday.
Shunichi Tanaka, chairman of the Nuclear Regulation Authority, said the ocean dump could be necessary as the country’s government prepares to present its plan for handling tainted water at the site that’s increasing by 400 tons a day.
Managing the water used to cool melted fuel at the Fukushima plant’s reactors has become a fundamental challenge for the utility known as TEPCO, which has struggled to contain a series of leaks including the loss of about 300 tons of contaminated water from a storage tank two weeks ago.
‘‘It is important for us to understand the need to make difficult judgments in order to avoid larger problems in the future,’’ Tanaka told reporters in Tokyo.
Contaminant levels must be brought below accepted limits through filtration or other treatments before the water is discharged, he said.
Japan’s Nuclear Emergency Response Headquarters may present its response to the water management crisis as early as Tuesday, Deputy Chief Cabinet Secretary Katsunobu Kato said, relaying comments Chief Cabinet Secretary Yoshihide Suga made to lawmakers. The government wants to present a ‘‘complete package’’ of steps to tackle the water problem, Suga said, according to Kato.
TEPCO’s challenge was further illustrated Sunday when the utility said it had found a new radioactive leak, capping its worst month since the March 2011 earthquake and tsunami caused reactors to melt down.
The company said it had halted the contaminated water leak from a pipe near an area of high radiation levels discovered on Aug. 31. Of the hot spots found over the weekend, one recorded radiation of 1,800 millisieverts per hour around the bottom of a bolted-flange tank storing water used to cool melted reactor cores. That’s 18 times the level reported at the same spot on Aug. 22, TEPCO said.
The weekend’s findings probably reflect TEPCO’s beefed-up monitoring crews finding contamination that was missed earlier, former nuclear engineer Michael Friedlander said.