APR: your source for nuclear news and analysis since April 16, 2010

Monday, April 25, 2011

Further brief details on Fukushima Daiichi

Just to add a couple details from the general Japanese press on the situation:

TEPCO has shown a map of the rad levels on site. The discovery of a general 300 mSv area (30 R/hr) has been noted and our previously reported finding of a piece of debris reading 900 mSv (90 R/hr) has been repeated. This helps explain why TEPCO is now working so hard on using the remote controlled vehicles to clear the debris from the area of the reactor buildings.

Going now to the water problem, TEPCO now sees a rising water level in the No. 3 and No. 4 plant turbine buildings... and this water is now much more highly contaminated than it was one week ago. There doesn't seem to be much use in speculating where the water in each building is coming from; it may be one water mass, essentially, through fissures and voids in the ground / concrete / foundations and there could be water from all the plants in communication. The same tired line is obvious; TEPCO needs to re-establish some sort of recirculating cooling ASAP. At least as of this time repeating this line we can also say that TEPCO clearly knows this and has already ordered equipment (the heat exchangers) to make it happen.

In the meanwhile TEPCO tries to stay ahead of the water storage problem by buying and shipping in storage. Tanks are being placed on site, and so far as we know work on the mega-float continues.. this particular tank having arrived April 7th at Yokohama for modification for this operation.

Here are some interesting TEPCO press photos. First, a Komatsu PC200 excavator with claw attachment in place of the normal bucket. The arm of this machine has the number 2.9t on it which we assume means lift capacity of 2.9 metric tons. In the background is the lead-shielded mobile operating center for the remotely controlled equipment such as the Komatsu.

And we also have a look inside the control area for remote controlled equipment. We aren't sure if this is the inside of the mobile vehicle or not, but it might be. Again, this is a TEPCO press photo.

9:00 PM Eastern Monday 4/25


  1. I've been quoting from you and pointing to your items over at bravenewclimate.org -- thanks for the ongoing technical info (and for adding cites to sources you're using, which really helps). Your description of the "catch-22" is the clearest I've seen.

    Question--I'm wondering about the idea of building a cofferdam around the entire site to contain the radioactive material carried by the leaking cooling water. Has any soils data from the site construction been published? The cofferdam is described as going down to an 'impermeable layer' -- ending with the plants sitting on mud instead of solid ground.

    I hope they're drilling a test well from the side to sample water flowing through the groundwater over time--and that they know which direction the 'impermeable layer' tips to know which direction groundwater is moving.

  2. er, make that: bravenewclimate.com (not .org)