Frozen wall test

February 25, 2014

Frozen wall test to begin at Fukushima plant

http://www3.nhk.or.jp/nhkworld/english/news/20140226_03.html 

Engineers are to start testing a plan to build frozen walls at the Fukushima Daiichi nuclear power plant.
The government and the operator of the plant will carry out the plan to deal with the massive buildup of radioactive wastewater.

The government and Tokyo Electric Power Company are to begin the test on March 11th at the earliest.

The amount of wastewater has been increasing as 400 tons of groundwater is flowing beneath the facilities from nearby mountains every day.

The government plans to spend more than 300 million dollars to build frozen walls around the Number One to Number 4 reactors. The test will be conducted at the Number 4 reactor.

Engineers will drive steel pipes to a depth of 30 meters in an area measuring 100 square meters. They will inject liquid coolant at a temperature of minus 40 degrees into the pipes. The refrigerant is expected to freeze the soil in a month or so.

Engineers will check whether the frozen wall can stop the flow of groundwater despite the presence of piping or other structures beneath the soil. They will also study how to replace the pipes.

The government and TEPCO aim to start building full-scale walls in the fiscal year that starts in April. They will be 35 meters deep, nearly 5 meters more than initially planned. This is because radioactive substances were detected in groundwater taken from a deep layer last December.

Some engineering and geology experts warn that the walls could change groundwater flows and have a significant impact on underground features.

They also doubt that frozen walls of such an unprecedented size can be properly maintained over the long term.

Feb. 25, 2014 - Updated 22:20 UTC