Trenches almost clear

July 31, 2015

TEPCO removes radioactive water from No. 3 reactor trench at Fukushima plant

http://mainichi.jp/english/english/newsselect/news/20150731p2a00m0na018000c.html

Tokyo Electric Power Co. (TEPCO) announced on July 30 that it had completed the removal of radioactive water collected in the trench for the No. 3 reactor at the crippled Fukushima No. 1 Nuclear Power Plant.

With the removal of the No. 3 reactor's trench water, the work to clear the trenches of the No. 2 through No. 4 reactor trenches is almost over. In addition to lowering the risk of highly contaminated water leaking into the ocean, the removal of the radioactive water sets the stage for the creation of walls of frozen dirt around the No. 1 through No. 4 reactors to block any more underground water from flowing onto the premises of the reactors.

According to TEPCO, after the disaster struck the plant, the amount of contaminated water in the trenches measured 4,500 tons in the No. 2 reactor trench, 5,800 tons in the No. 3 reactor trench and 660 tons in the No. 4 reactor trench, for a total of around 11,000 tons. In the water from the No. 2 and No. 3 reactors, where meltdowns occurred, the water contained up to 100 million becquerels of radiation per liter. The Nuclear Regulation Authority had been concerned that the water would escape into the ocean.

The trench for the No. 4 reactor still has around 60 tons of water in it, but at up to 100,000 becquerels per liter, the radiation level is low compared to what was in the No. 2 and No. 3 reactor trenches.

The water from the trenches had previously been planned to be removed by April 2014, but a plan to freeze the areas where the reactor buildings and the trenches connect and stop the flow of water into the trenches failed. The plan was changed to pouring in a special kind of concrete to fill up the trench while draining out the water, setting back the schedule considerably. The draining of the No. 2 reactor's trench was completed around the end of June this year.