Last updated on March 1, 2013
TEPCO has released a video that shows work being done at the Fukushima plant. Very interesting to watch.
One gets a real sense for the devastation the tsunami inflicted while watching that clip.
TEPCO also recently released this PDF file that gives an overview of work being done. I will add some pictures from it:
In the above picture one can see how they plan to rig up the new heat exchangers for reactor 1. Within the reactor building, but outside the containment, they will put a water to water heat exchanger. They will pump water from within the containment through this heat exchanger, where it transfers the heat to a secondary circuit that in turn flows to a heat exchanger outside of the reactor building that dumps the heat to the air. This is the original plan TEPCO had before they realized the full extend of the damage to the number 1 core and containment, so it is not sure they will progress as described. But the secondary heat exchanger and its piping is already being built.
Tepco also shows the above picture on how they plan to reuse leaking water from the containment as cooling for the reactor. It is not clear how the two plans are connected to each other. I would assume the second plan is the one that is going to be used instead of the first plan. Instead of taking water directly out of the containment they will use the existing leakage paths, purify the water and pump it back into the reactor.
For the number 2 reactor shown above the main problem is to stop the leakage from the suppression pool. They plan to excavate the reactor building in order to access the room where the suppression pool is housed and then fill the entire volume with grout. Considering that (probably) the suppression pool is leaking at number one as well then maby this plan will be implemented there as well (just my speculation).
Both in unit 2 and 3 are they planning to reuse the leaking water in the same manner as in unit 1.
In the rest of the document they give some basic information on how they plan to clean the massive amounts of contaminated water that exists on the site, some details on the protective building they want to build around the reactors and how to prevent more contamination of soil, water etc. Well worth scrolling through, massive work is certainly ongoing at the site and it seems TEPCO has a solid plan that they are implementing. Of course more surprises will without a doubt pop up during work, but it looks promising. We are still waiting for more in depth information on the situation of the number 2 and 3 reactors.
English blogs:
All Things Nuclear TEPCO Says Core of Unit 1 Melted
Atomic Power Review Fukushima Daiichi update, Weds. morning 5/18
English News:
New York Times Venting Failure in the Nuclear Reactors at Fukushima Daiichi
Reuters UK nuclear power gets green light
/Johan
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Nice, plate heat exchangers. My first summer job, ever 😀
PHEs are compact and easy to dismantle, I wonder how you will clean them under the current conditions though.
Simple as heck. Just dip the in some acid (sorry can’t tell you what or which, well I could but then I’d have to kill ya). The acid can be regenerated using ion-exchange resin which incidently will retain all the radioactive stuff. Neat, eh?
This seems bad:
“http://www.asahi.com/english/TKY201105130370.html
TEPCO concealed radiation data before explosion at No. 3 reactor
Tokyo Electric Power Co. concealed data showing spikes in radiation levels at the Fukushima No. 1 nuclear power plant in March, one day before a hydrogen explosion injured seven workers.
The Asahi Shimbun obtained a 100-page internal TEPCO report containing minute-to-minute data on radiation levels at the plant as well as pressure and water levels inside the No. 3 reactor from March 11 to April 30.
The data has never been released by the company that operates the stricken plant.
The unpublished information shows that at 1:17 p.m. on March 13, 300 millisieverts of radiation per hour was detected inside a double-entry door at the No. 3 reactor building. At 2:31 p.m., the radiation level was measured at 300 millisieverts or higher per hour to the north of the door.
Both levels were well above the upper limit of 250 millisieverts for an entire year under the plant’s safety standards for workers. But the workers who were trying to bring the situation under control at the plant were not informed of the levels. ”
I have not seen this confirmed or explained anywhere else. Was this data concealed from the Japanese government?
“Generator trucks proved useless at Fukushima plant
The operator of the stricken Fukushima Daiichi nuclear plant says dozens
of power-generating trucks brought to the plant just after the March
11th disaster mostly proved to be useless.”
“..”
“plant operator TEPCO says debris strewn across the compound and flooded switchboards hampered the trucks’ set up.
The utility says a switchboard for the No.2 reactor was finally wired to
one of the generator trucks about 24 hours after the disaster.
But moments later, a hydrogen explosion at the neighboring No.1 reactor
fried the wiring and cut off the power supply from the truck.
Another hydrogen explosion 2 days later at the No.3 reactor damaged generator vehicles with chunks of flying concrete.”
http://www3.nhk.or.jp/daily/english/17_11.html
I wonder how much it would cost to make “emergency assist points” (or whatever they should be called), say 200 meters away from the reactor buildings. Nothing special really, just places where you can plug in any emergency assist power or water, a bit away from the reactors. (Ofc, power lines and water pipes running towards the reactor.)
Another aspect would be designing multi-reactor power stations with larger distances between individual reactors. I am curious about how much this would cost, intuitively it seems increased costs for increased land usage would be very minor.
To get the reserve switchboard above the tsunami on dry land need not be far, or just 5 meter up on the reactor building itself. It would probably not have been an hydrogenexplosion, if an operating switch board survived. Seems easy. But the problem was that no preparations were made at all for a tsunami as high as it was! Seemed beyond imagination! Read about this on my comment in the forum http://nuclearpoweryesplease.org/forum/viewtopic.php?f=16&t=213
You made a question on another blog
“Om man jämför BEIR VII med RISC-RAD, finns det några avgörande skillnader?” Jag har bara läst en sammafattning av RISC-RADs slutredovisning. Jag har bett om den utförligare slutrapporten två gånger, men inte fått den. Jag törs därför inte ge ett mer utförligt svar. Men min gissning är att svaret är nej.
Locking in data and scientific articles is such a shameful thing. It is time more things went open access.
I hope you get the report soon, Dag!
Regarding radiation doses, does this blog post seem to be correct? It is made recently by the signature Radtact:
“In 1,193 cases, workers had internal exposure to radiation of more than 10,000 cpm. ”
“…”
“For Gamma, the device detects x-rays down to 10 keV through end window,
or 40 keV through case. Calibration is 1000 CPM = 1 mR Cs-137 per hour
(indicated in the picture above). So for example, if we were measuring
cpm with this particular unit, we will be able to establish a range of
absorbed dose readings based on what was mentioned in the article. ”
“10,000 cpm = 10 milliREM per hour. That equals 100 microSv/hr, or 876 milliSv/year.”
From http://falloutphilippines.blogspot.com/2011/05/more-revelations-about-radiation.html
The data was taken from the article “Nuclear plant workers suffer internal radiation exposure after visiting Fukushima”
http://mdn.mainichi.jp/mdnnews/news/20110521p2a00m0na021000c.html
800 mSv in committed dose would be awful. There still are reactors in intensive care, and a lot of stuff to clean up. (Frankly, if there was no need to work in the area, I would recommend just putting tarpaulins over the area, to keep rain water out. Then you leave it for the robots, or for later when the hottest stuff have decayed.)