23 Septembre 2014
August 20, 2014
The Tokyo Electric Energy Corporation (TEPCO) announced today their failure to create an ice wall in a part of the underground tunnel connecting to a damaged reactor at Fukushima No. 1 power plant. This has not stopped TEPCO from pursuing an alternative.
The Fukushima Daiichi nuclear disaster has now become the world's worst "man-made" disaster ever, and one that is continuing without any end in sight. The difficulty in attempts at stopping the seepage of radioactive water has proven to be an insurmountable task, as the notification from TEPCO officials today has proved.
Leaking water the most pressing problem
The earthquake and resulting tsunami on March 11, 2011 resulted in the meltdown of three of the plant's six reactors. It wasn't until August of 2013 that it became clear that the most pressing problem affecting cleanup was the escaping radioactive water. At that time, it was estimated the cleanup would take several decades.
TEPCO officials have tried several remedies, yet radioactive water has continued to escape into the ocean. As late as August 20, 2013, it was discovered that radioactive water had been continually leaking into the Pacific Ocean, as many people suspected, but TEPCO had denied. This discovery resulted in the government taking "emergency measures" on August 27, 2013.
In trying to contain and then reduce the radiation levels of all the groundwater that continues to seep into the reactor basements, TEPCO has been trying several unique remedies, and to date, none of them has worked. Earlier this year, they started construction of an "ice wall" that would freeze the contaminated water, sealing it forever, but that in itself is questionable.
Alternative plan: Dump the treated water in the ocean
Up until now TEPCO has been pumping the contaminated water up out of the basement areas, and storing it in large storage tanks on the site of its Fukushima reactor. About five days ago, TEPCO officials said they were running out of space to store the contaminated water. They made a request to the Nuclear Regulatory Authority (NRA) to treat the radioactive water and then dump it into the ocean.
We know we have to get an agreement from the relevant government authorities, the prefecture and local fishing unions,” a TEPCO spokesman said recently. TEPCO is well aware of what the public reaction will be, locally and worldwide. A TEPCO official told Asahi Shimbun, "We would never consider dumping the water into the ocean unless we received the consent of local residents. The water close to the plant buildings is already contaminated. Fishermen are sure to raise objections to the plan, so it will be difficult to gain their understanding."
Diagram of proposed pumping of groundwater, treatment and disposal into the ocean.
The plan is meant to reduce the amount of groundwater flowing into buildings that already have contaminated water. It also involves wells called sub-drains that have already been built around the buildings on the site. The two-pronged measure would allow uncontaminated groundwater to be pumped directly into the ocean, and through the use of the sub wells, the contaminated water would be pumped up, treated and then dumped into the ocean.
Nuclear Regulatory Authority critical of TEPCO
Shunichi Tanaka, NRA chairman was critical of TEPCO when he spoke at a news conference on August 7, according to the Wall Street Journal. Saying the stricken company needed to get their priorities straight, and place greater emphasis on solving the issues with the greatest risk.
“The biggest risk is the trench water. Until that matter is addressed, it will be difficult to proceed with other decommissioning work,“ Shunichi Tanaka, chairman of the Nuclear Regulation Authority, said on Wednesday at his weekly news conference. “It appears that they are getting off track,” he told reporters.
Another failure announced today
Tanaka was referring to the now failed attempt by TEPCO to freeze a section of the underground tunnel that connects to a damaged reactor,blocking the escape of the highly radioactive water. By freezing the water, TEPCO thought they would have a wall of ice blocking the flow of water between the turbine building and the tunnel.
Diagram showing failed proposal at blocking tunnel with an ice wall.
This tunnel holds about 5,000 to 6,000 tons of highly-contaminated water, and since July the power company has used over 400 tons of ice and dry ice trying to create the ice wall. The temperature never fell low enough to freeze the radioactive water. TEPCO told the NRA today they are going to try using filler in an attempt to slow the flow of water until maybe the freeze they want takes affect.
TEPCO's past history with the Fukushima power plant has greatly influenced public opinion against nuclear power use in Japan. The disaster ultimately ended up being labeled a "man-made" disaster with blame being put on, among other things, poor judgement in locating the plant in an active seismic zone. Probably even worse has been the cover-up by TEPCO officials of the true conditions at the site. And this issue is still a problem today.