Tokyo Electric Power Co. (9501)’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.
Nuclear Regulation Authority Chairman Shunichi Tanaka said today 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.
“It is important for us to understand the need to make difficult judgments in order to avoid larger problems in the future,” Tanaka said of the possible ocean discharge during a speech to reporters in Tokyo.
Tepco boosted the number of tank-inspection patrols from twice a day to three times a day after last month’s 300-ton leak, Yoshikazu Nagai, a company spokesman, said by phone. Patrols are increasing further to four times a day beginning today, when the number of inspection staff grows to 60 members from 10, he said.
The company also planned to install gauges on all of its tanks to monitor changes in water levels that suggest leaks, Nagai said. Those water level checks are currently done by measuring the temperature of the tanks’ outer walls, he said.
“They threw these tanks together, they’re exposed to the elements and now that they have more people looking at it with a higher degree of diligence, they’re finding leaks,” said Friedlander, who spent 13 years operating U.S. nuclear plants. “Those leaks have probably been around for quite some time and they’ve probably been growing because until now they haven’t been doing any work on them.”
Radiation levels Tepco disclosed at the weekend don’t raise an immediate concern for the general public because the site is off limits, Tetsuo Ito, head of Kinki University’s Atomic Energy Research Institute, said yesterday by telephone.
Direct exposure to 1,800 millisieverts for four hours can be lethal, but it’s not life-threatening for Tepco’s inspectors as they don’t stay in one spot for four hours, he said.
Tepco’s unit for filtering such contaminants, known as ALPS, was taken off line due to corrosion on Aug. 8, just months after beginning operation. Trade Minister Toshimitsu Motegi said last month that Tepco was being given until mid-September to restart the system.
“If we do decide to discharge into ocean, we will make every effort to ensure that contaminant levels are below the accepted limits,” Tanaka said. “One way to achieve it is to use the ALPS system, which does remove many radioactive elements.”