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Why do they need larger arm then? Just to spray water from further away?

I heard they are going to use dust absorbing powders to clean the air, and then work with concrete. Water contamination will remain a problem though.

by das monde on Fri Apr 1st, 2011 at 03:24:45 AM EST
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Why do they need larger arm then?

Based on the photo of concrete pump truck action at the No. 4 reactor below, the currently used vehicle seems only enough to reach the edge of the buildings, so I guess it will help to better reach the parts of the top floor further away from accessible sides. (I'm not sure though whether the arm can be telescoped out further, but none of the photos I shaw showed it reaching further.)

I heard they are going to use dust absorbing powders to clean the air

No, resins to prevent dust on the ground being picked up by wind.

Fukushima plant groundwater likely contaminated despite data error | Kyodo News

In an effort to prevent radioactive dust from being dispersed by wind and rain from the plant, TEPCO will begin a test spraying of a water-soluble resin, which has coating effects, later in the day.

As a result of hydrogen explosions, masses of debris have been strewn around the site, which was ravaged by the March 11 earthquake and tsunami. A total of 60,000 liters of resin will be sprayed over a period of two weeks.



*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Fri Apr 1st, 2011 at 03:57:37 AM EST
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Would you expect them to solve the problems just by spraying water? Apparently they can't get it inside reactors anyway.
by das monde on Fri Apr 1st, 2011 at 06:11:36 AM EST
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Depends on which problem you mean. Spraying water is irrelevant to the reactor cores, they are now pumping freshwater across pipes to cool those. For the cooling of the spent fuel ponds, spraying water does solve the problem, but a permanent way of pumping water across a heat exchanger would be desirable eventually, and of course a cover overhead, but first the wreckage would have to be removed for anything stable. I'm not sure what problem concrete would be supposed to solve – maybe it would block aerial fallout, but that only if cooling efforts are abandoned (both in the spent fuel pools and reactor cores) and all steam is let off first, but then you have complete meltdowns and a bigger problem underneath the reactor.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Fri Apr 1st, 2011 at 06:20:53 AM EST
[ Parent ]
Do we know that the pools' structure hasn't been damaged so that water leaks out through cracks? Those explosions have been quite spectacular.

Economics is politics by other means
by Migeru (migeru at eurotrib dot com) on Fri Apr 1st, 2011 at 06:21:54 AM EST
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Do we know that the pools' structure hasn't been damaged so that water leaks out through cracks?

No we don't. (We don't know how far the pool was re-filled, either.) However, we calculated that the No. 4 spent fuel pond heats at least at 2°C/h when not boiling and evaporates at 3.7 tons an hour when boiling, that's 88.8 t per day. The amounts pumped into the No. 4 reactor's spent fuel pool (see here) were 125-150 t at a time, the last time 140 t two days after the previous filling. That is in the right ballpark if you take the re-heating of water cooled by the previous addition into account.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Fri Apr 1st, 2011 at 06:34:21 AM EST
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