Fukushima’s giant ice wall fails to stop water leaking into radioactive area

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March 8, 2018
A giant ice wall constructed underneath the ill-fated Fukushima Daiichi power plant in Japan is failing to prevent groundwater from seeping into it, according to a new report from Reuters.
 
The failure to contain the water is preventing clean-up teams from removing the last of the dangerous radioactive fuel, seven years after a tsunami hit the plant and triggered a catastrophic meltdown.
 
The refrigeration structure, which resembles giant ice lollies, was completed in 2016 and was an attempt to limit the amount of radioactive water created by the incident.
 
The aim is to freeze the soil into a solid mass that blocks groundwater flowing from the hills west of the plant to the coast.
 
At the time of the ice wall construction, nearly 800,000 tonnes of contaminated water was being stored in 1,000 huge industrial tanks at the site.
 
Data released from operator Tokyo Electric Power Co (TEPCO) showed that water leakage has actually got worse since the structure was turned on.
 
An average of 141 metric tonnes of water per day seeped into the reactor and turbine areas, compared to an average of 132 metric tonnes a day during the prior nine months.
 
The structures cost around 34.5 billion yen (£233m) in public funds and consist of approximately 1,500 tubes filled with brine, cooled to minus 30°C, and buried 30 metres underground.
 
“I believe the ice wall was ‘oversold’ in that it would solve all the release and storage concerns,” said Dale Klein, the former chairman of the US Nuclear Regulatory Commission and the head of an external committee advising Tepco on safety issues.
 
“The hydrology of the Fukushima site is very complicated and thus the exact water flow is hard to predict,” he said, “especially during heavy rains.”
 
Overall, Tepco says a combination of drains, pumps and the ice wall has cut water flows by three-quarters, from 490 tons a day during the December 2015 to February 2016 period to an average of 110 tons a day for December 2017 to February 2018.
 
It is hard to measure exactly how much the ice wall is contributing, Tepco officials say, but based on computer analysis the utility estimates the barrier is reducing water flows by about 95 tonnes a day compared to two years ago, before the barrier was operating.
 
However, it expects to run out of space to store the water by 2021, so the decommissioning process needs to be completed as quickly as possible.
 
In 2016, the estimate for the total cost of the clean-up operation increased to 22.6tr yen (£151bn), more than double the previous estimate.
 
According to a Greenpeace report on Fukushima, published last week, the people, towns and villages in the surrounding area are still being exposed to excessive levels of radiation. A ground-level study conducted by an international research team also found that uranium and other radioactive materials, such as caesium and technetium, were present in tiny particles released from the damaged nuclear reactors.
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TEPCO: Frozen soil wall effect limited

 

2018/03/01
Tokyo Electric Power Company, or TEPCO, says an underground frozen soil wall around its Fukushima Daiichi nuclear plant has had a limited effect in reducing groundwater contamination.
 
The 1.5-kilometer-long barrier is designed to keep groundwater from flowing into reactor buildings that were damaged by the March 2011 earthquake, tsunami and nuclear meltdowns.
 
The wall was expected to be the main defense against groundwater contamination, as about 500 tons of water was being tainted daily by radioactive substances.
 
TEPCO officials on Thursday estimated the amount of new contaminated water to have decreased by about 95 tons a day from before the wall was built.
They said the estimate is based on 3 months of data including that from before and after the wall was almost completed last November.
 
TEPCO had introduced a so-called sub-drain system for pumping up water from wells dug around the buildings.
 
The officials estimated that the 2 measures resulted in a decrease of 380 tons of tainted groundwater a day, suggesting the wall’s effectiveness is limited and lower than that of the drain method.
 
The government plans to ask experts to look into whether the utility’s estimate is accurate.
 
Public funds worth over 300 million dollars have been used to build the wall. Its annual operating cost exceeds ten million dollars.

 

Groundwater level plunges near Fukushima reactor

The reason they didn’t divert the groundwater around Daiichi is because they need it to keep all the missing stuff cool & contained, relatively speaking …

“A sharp fall in the groundwater level just outside reactor buildings could cause contaminated water to leak from inside the buildings.”

 

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The operator of the Fukushima Daiichi nuclear power plant says the groundwater level briefly plummeted near a building that houses one of the crippled reactors.

Tokyo Electric Power Company, or TEPCO, says the fall was observed in a monitoring well about 11 meters southwest of the No.4 reactor building on Wednesday.

The utility says the groundwater level temporarily sank roughly 1 meter below the level of contaminated water inside the reactor building.

The firm says the groundwater rose above the usual level 23 minutes later.

A sharp fall in the groundwater level just outside reactor buildings could cause contaminated water to leak from inside the buildings.

TEPCO says it assessed the density of radioactive substances in the well water on Thursday and has confirmed no leak of contaminated water took place.

TEPCO stopped pumping out water from the well and reported the case to relevant local governments and the Nuclear Regulation Authority.

The company says it is conducting an investigation, suspecting that improvement work on another well 6 meters away may have caused the drop.

The utility publicized the drop on Thursday, one day after the phenomenon was recorded. The firm apologized for the delay in disclosure, saying it initially decided a problem had developed with the well’s water gauge as the water level in a nearby well remained unchanged.

The No.4 reactor building experienced a hydrogen explosion, but not a meltdown, during the 2011 accident.

https://www3.nhk.or.jp/nhkworld/en/news/20170804_06/

Ice wall at Fukushima plant to be examined

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Japanese government officials and the operator of the crippled Fukushima Daiichi nuclear plant say they plan to dig and check the ground around reactors. They want to see if an ice wall installed there is working as intended.

The underground ice wall is meant to prevent groundwater from getting into the damaged reactor buildings and becoming contaminated.

Tokyo Electric Power Company has been creating a 1.5 kilometer-long barrier of frozen earth since March. The ice wall is formed by circulating coolant in pipes buried around the reactor site.

Engineers believe that except for an area on the plant’s hillside, the freezing work has been completed.

Government and TEPCO officials have relied on thermometers in the ground to determine if the soil is frozen. But Japan’s nuclear regulator has urged them to more precisely check the conditions underground and the ice wall’s effectiveness.

This month, workers will dig several meters into the ground south of the Number 4 reactor to directly check the condition of the frozen wall. The area was chosen due to its relatively low radiation level.

Later this month, officials from a government task-force will inspect the site.

TEPCO’s decommissioning roadmap calls for most of the contaminated water to be removed from the reactor buildings in 2018. To achieve this, the ice wall needs to be completed and effectively preventing groundwater from flowing into the reactor buildings.

http://www3.nhk.or.jp/nhkworld/en/news/20161102_27/

Fukushima Untreated Bypass Groundwater Dumped into the sea

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Up to October 14, 2016, Tepco has discarded 137 times Fukushima Daiichi untreated groundwater from the bypass into the sea, all totalling now 222,816 tons (58,861,760 gallons).

That not including the 300+ tons a day of untreated groundwater flowing through the plant and into the ocean 24/7 for 5.6 years now.
http://www.tepco.co.jp/nu/fukushima-np/info/baypassold-j.html

Fukushima Daiichi Contaminated Groundwater Pouring into the Sea

 

Fukushima Daiichi Groundwater Rises from Typhoon N°16 Sept. 21, 2016

« Groundwater level rises in the aftermath of Typhoon 16, due to its heavy rain the groundwater now reaches now the surface.

It is unclear as whether or not the groundwater has been contaminated with radioactive material as it poured out into the sea, To be determined later, Tepco says. »

http://www.news24.jp/sp/articles/2016/09/21/07341567.html

 

Tepco pumping groundwater from Fukushima plant.

The operator of the Fukushima Daiichi nuclear power station says it is pumping groundwater from under the plant to prevent contaminated water from leaking into the adjacent port.

Tokyo Electric Power Company says the heavy rains brought by Typhoon Malakas have raised the underground water levels around the plant’s embankments.

TEPCO officials say they added pumps to prevent the groundwater from rising further. They say the water rose nearly to the surface shortly before 10 PM on Tuesday.

The officials say this has prevented rain from permeating the ground and increased the risk that the rainwater could become contaminated and flow into the port.
The utility says that while it is pumping the groundwater to prevent leakage, it will measure the radioactive substances in the water.
http://www3.nhk.or.jp/nhkworld/en/news/20160921_09/

Groundwater to be released into the sea on Monday

The operator of the Fukushima Daiichi nuclear plant plans to start releasing groundwater from around reactor buildings into the sea next Monday.

The government and the operator, Tokyo Electric Power Company, are to formally decide on the discharge date on Wednesday. The water has already been decontaminated.

Officials hope the move will help to curb the accumulation of radioactive wastewater in the reactor buildings. The contaminated water is increasing at a rate of 300 tons a day as the groundwater flows in.

The officials plan to first release some 4,000 tons of water pumped up from the wells around the buildings on a trial basis since August last year.

They say they will continue to pump up water and release it after removing radioactive materials.

Later this week, the utility also plans to resume the construction of steel walls along the coast to stop the groundwater seeping directly into the sea.

The construction work has been suspended until the release of the groundwater becomes possible. 

Source: NHK 

http://www3.nhk.or.jp/nhkworld/english/news/20150909_05.html