Wednesday, August 16, 2017

Fukushima's Ice Wall Nearing Completion


Fukushima Daiichi's ice wall is nearing completion. The Mainichi has a detailed and quite interesting article about the problems with the ice wall here:
High-priced Fukushima ice wall nears completion, but effectiveness doubtful August 16, 2017, https://mainichi.jp/english/articles/20170816/p2a/00m/0na/016000c

But while 34.5 billion yen from government coffers has already been invested in the wall, doubts remain about its effectiveness. Meanwhile, the issue of water contamination looms over decommissioning work.
The problems with the ice wall are myriad and were identified early on in the process, as noted in the article:
Furthermore, during screening by the NRA, which had approved the project, experts raised doubts about how effective the ice wall would be in blocking groundwater. The ironic reason for approving its full-scale operation, in the words of NRA acting head Toyoshi Fuketa, was that, "It has not been effective in blocking water, so we can go ahead with freezing with peace of mind" -- without worrying that the level of groundwater surrounding the reactor buildings will decrease, causing the contaminated water inside to flow out.  
So, the main problem with the ice wall seems to be that it is not effective in blocking radioactive water, which was its main design purpose.

That is the bad news. The good news is TEPCO reports success in reducing the volume of contaminated water produced everyday from 400 tons to approximately 130 tons.

Still, 130 tons is an inconceivable amount of contaminated water to produce daily. Much of this water is captured and filtered but TEPCO admits it can only remove some of the radionuclides found in the water:
Tainted water is treated using TEPCO's multi-nuclide removal equipment to remove 62 types of radioactive substances, but in principle, tritium cannot be removed during this process.
I've posted previously about the hazards of tritium (e.g., see here).

I imagine that tritium is not the only radioactive isotope that resists filtration. For a few years TEPCO could not filter strontium. The ALPS water treatment system allegedly was finally fixed so that strontium could be filtered but my bet is that plenty of strontium-laced water has ended up in the ocean and in the water table.

The completion of Fukushima's ice wall seems a hollow victory.

I'm a bit more optimistic about the new cover on unit 3, which seems to have reduced the visible atmospheric emissions from that area of the plant:


The new cover on unit 3 is visible in the background of this screenshot, behind the tall white vent stack.

Now if TEPCO can figure out a way to cool down the common spent fuel pool, whose building seems steamy recently: