The call on Wednesday comes just two days after a worker fell into one of the hundreds of tanks used to store contaminated water at the plant during an inspection, a fatal accident that has refocused attention on the need for improved safety measures and a longer term solution for the huge amounts of water in storage.
“Tokyo Electric Power must consider whether it (storing the water) is really necessary,” said Shunichi Tanaka, chairman of the Nuclear Regulation Authority, at a regular board meeting Wednesday. “It is surely harmful if it leads to the death of workers.”
The regulator discussed Wednesday a draft timetable for action by Tepco to address risks at the plant that sets out a 2017 start for discharging the water. The draft is likely to be approved next week.
The International Atomic Energy Agency already recommended more than a year ago that Tepco consider releasing water with low level tritium contamination in a controlled way so that it could focus on other issues.
A Tepco spokesman, speaking after Mr. Tanaka’s remarks, said the company wasn’t currently considering releasing the water into the ocean.
Contaminated water has been a constant headache for the operator of the plant since the triple meltdowns in March 2011. A large amount of groundwater is flowing into the site, adding 300 to 400 tons to the amount of highly contaminated water at the plant on a daily basis.
Tepco is using a processing system to remove radioactive material from the highly contaminated water, but the system is unable to take out the tritium. Tepco has been storing the tritium-contaminated water in about 1,000 tanks, but is reluctant to release it into the ocean to avoid adding to tension with local communities and criticism from neighboring countries and some nations with a Pacific Ocean coastline.
But the power company is close to running out of space to build new tanks at the plant and workers are increasingly under pressure to juggle their other duties with the ever-increasing workload of tank management, prompting the IAEA call in late 2013.
Tritium is considered one of the least harmful radioactive materials at nuclear plants. Water contaminated with tritium is discharged from plants elsewhere in the world after dilution.
However, there is no detailed study about tritium’s long-time effect on animal genes. Mamoru Takata, a Kyoto University professor and expert on radiation’s long-term effects, said monitoring would be necessary to detect any worrisome signals.
Plan OK'd for dumping Fukushima's water into ocean after treatment
The plan is one of the measures aimed at curbing the amount of contaminated water building up at the seaside complex. But it remains uncertain when the operator may actually release the water.
Local fishermen have registered strong concerns that dumping the water will heighten consumer apprehension about marine pollution, and TEPCO has said it will not release the water unless it obtains consent from the locals.
The company plans to treat water pumped up through 42 of its wells at a water treatment facility at the plant. After treatment, the water will be temporarily stored in tanks to check whether the amount of radioactive materials left in it is within levels deemed safe for release into the sea.
According to TEPCO, the amount of radioactive water at the complex is believed to be increasing by some 350 tons every day as fresh, untainted groundwater is seeping into reactor buildings and mixing with toxic water generated in the process of cooling the reactors that suffered meltdowns in the 2011 nuclear disaster.
Separately, TEPCO is running a groundwater bypass that is aimed at pumping up untainted groundwater before it mixes with radioactive water. Since the earthquake- and tsunami-triggered disaster, the operator has dumped such water into the Pacific numerous times after confirming its safety.