3 Juin 2014
June 3, 2014
TOKYO (Kyodo) -- The operator of the crippled Fukushima Daiichi nuclear power plant began construction on Monday of a huge underground ice wall around four reactor buildings, a key measure to tackle the toxic water buildup at the complex.
Under the government-funded project, 1,550 pipes will be inserted deep into the ground to circulate coolant and freeze the nearby soil. The measure is aimed at preventing groundwater from seeping into the buildings and mixing with heavily contaminated water.
Tokyo Electric Power Co. plans to finish constructing the 1.5 kilometer ice wall and start operating it by the end of March 2015. It will then take around a few months to fully complete the process of freezing the soil, a TEPCO official said.
Late last month, nuclear regulators gave the green light to TEPCO to implement the unprecedented project after the utility was able to convince them that it will not trigger significant sinking of the ground supporting the buildings.
On Monday afternoon, workers at the plant started digging a hole to place one of the pipes near the No. 1 reactor building. But the company said it still needs the Nuclear Regulation Authority's permission for work that could undermine the plant's safety.
The buildup of radioactive water at the complex is a major problem facing workers at the plant, where toxic water is increasing by around 400 tons per day due to the inflow of groundwater into the Nos. 1 to 4 reactor buildings.
In an another effort to deal with the toxic water problem, TEPCO said Monday it had dumped into the Pacific Ocean 833 tons of groundwater that is pumped out through wells before it can flow into the reactor buildings, the third such release, bringing the total volume of water released under a so-called groundwater bypass system to 2,035 tons.
June 2, 2014
Tokyo Electric Power Co. on Monday started building a huge underground ice wall around the Fukushima No. 1 nuclear plant to reduce the generation of toxic water at the crippled complex.
Under the government-funded project, 1,550 pipes will be inserted into the ground to circulate coolant and freeze the surrounding soil. The measure is aimed at preventing groundwater from seeping into the plant’s four cracked reactor buildings and mixing with heavily radioactive water leaking out of them.
Tepco, as the beleaguered utility is known, plans to finish the 1.5-km wall and have it up and running by the end of March 2015. It will then take a few months or so to fully freeze the soil, a Tepco official said.
Late last month, nuclear regulators gave the green light to the unprecedented project after the utility succeeded in convincing them that it will not trigger significant subsidence that could further endanger the buildings. Evidence of land subsidence was seen at one of the buildings early in the crisis and more recently under some of the hundreds of water tanks set up on land overlooking the reactor buildings.
On Monday afternoon, plant workers started digging a hole for one of the pipes near the No. 1 reactor building, but the utility said it still needs the Nuclear Regulation Authority’s permission for work that could undermine the plant’s safety.
The buildup of radioactive water generated by the need to cool the damaged reactors is a major problem at the plant, where toxic water is building by around 400 tons a day due to the groundwater from the mountains that is entering reactor buildings 1 to 4.
In an another effort to deal with the toxic water problem, Tepco said Monday it had dumped 833 tons of untainted groundwater into the Pacific Ocean after intercepting it and diverting it through wells. The third release brought the total volume of clean water released under the so-called groundwater bypass system to 2,035 tons.
June 2, 2014
Work on frozen wall begins at Fukushima Daiichi
Workers have started building part of an underground frozen soil wall that will eventually surround the reactor and turbine buildings at the damaged Fukushima Daiichi nuclear power plant.
The wall is intended to prevent groundwater from nearby hillsides from flowing into the plant and mixing with highly radioactive materials there.
The government and the plant's operator, Tokyo Electric Power Company, plan to freeze the soil in a 1.5 kilometer zone at a depth of about 30 meters around the facilities of reactors No.1 through 4.
The Nuclear Regulation Authority has yet to authorize the entire construction plan as studies on some technical issues are still underway.
But with its partial approval, construction started from the hillside behind the No.1 facility on Monday afternoon. Workers began digging a hole for coolant pipes to be laid and setting up equipment needed to freeze the soil.
The plan is to start freezing the soil around next March, and to complete the wall about 1 month later.
NHK's reporters say the frozen soil wall is expected to keep groundwater from being contaminated.
But, they point out that the wall will also change the flow of groundwater into the plant, and this might cause radioactive water in the buildings' basements to seep out. The utility is being urged to work out measures to prevent this from happening.
They also note that the construction is taking place in a area with seaside tunnels filled with contaminated water that are linked to the reactor buildings.
An expert panel of the Nuclear Regulation Authority will continue to study what monitoring systems and measures need to be put in place.
Jun. 2, 2014 - Updated 11:43 UTC