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Reverse the sewers to cool Fukushima

Better than helicopters
 
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Sewers are underground, where you are safe from radiation. Robots to traverse and repair sewers are well established. The Fukushima plant certainly has sewer grates.

I propose that robots be deployed to traverse the sewer and come up inside the power plant. These robots could drag a firehose behind, or otherwise modify the walls of the sewer as it went. Once in, the sewer could be used to pump water or colder substances up into the plant rather than dropping them from high above and hoping they get in.

A robot effort like this could be done in tandem with whatever else is going on above ground.

bungston, Mar 17 2011

long lines problems http://www.aviation...heavylift/9023.html
500+ hours "experienced" for long-line helicopter loads [not_morrison_rm, Mar 19 2011]

Don't panic. http://www.theregis...8/fukushima_friday/
[hippo, Mar 19 2011]

We are the robots http://www.popsci.c...get-robot-assistant
[Ian Tindale, Mar 19 2011]

This Guy Is Falling http://languagelog....hisGuyIsFalling.jpg
[Ian Tindale, Mar 20 2011]

[link]






       I have huge sympathies for the Japanese. However, it seems to me that they're handling the reactor situation badly. The problem is "just" to get reasonable (not vast) tonnages of water into reactors and particularly into a storage pond, but it's as if they're not used to improvising and jury-rigging.   

       Even the latest helicopter air-drops of water seem to be very few and far-between, and are made from too great a height to have any effect. Dose rates above the reactors are said to be on the order of 100mSv/hr, which means that a fatal dose would be received in 10 hours. I can't believe that the danger to a pilot at low altitude for two minutes would be significant, even though it would be above "recommended" levels.   

       On the other hand, there are probably too many armchair experts on this one, and not enough information. Best wishes and best of luck to them.
MaxwellBuchanan, Mar 17 2011
  

       /probably too many armchair experts/   

       Can that happen?
bungston, Mar 17 2011
  

       At the moment, Fuk-D unit 2 has just been connected to power, while US UAVs observe from above. The coolant can now be pumped. Fuk-D unit 2 is the most problematic one, with suspected containment damage, although reactor 1,2 and 3 all have non-functional core cooling systems 1 (Emergency Core Cooling System) and 2 (Reactor Core Isolation Cooling System). Reactor unit 4 was defueled a the time, and reactor units 5 and 6 were on a scheduled outage and aren’t damaged and are safe (although their spent fuel pool temps are increasing).
Ian Tindale, Mar 18 2011
  

       All these robots doing our bidding for all these years but along comes a little radiation and where are they?
bungston, Mar 18 2011
  

       Come down off the furniture.
rcarty, Mar 18 2011
  

       would snow drop into place better than water?
po, Mar 18 2011
  

       I suppose abbreviating Fukushima Daiichi to Fuk-D is a bit indiscriminate, as there’s also Fukushima Daini.   

       “Dai” means number, level or place, and “ichi” is one, “ni” is two, “san” is three, “shi” is four, etc.
Ian Tindale, Mar 18 2011
  

       //snow// Comparatively larger ice pellets would drift less than water and be far superior in terms of temperature inhibition.   

       What I don't get is why they're using helicopters instead of real water-bombers.
FlyingToaster, Mar 18 2011
  

       I would tell GE the reactors are obviously defective (ie, on fire) and to pick them up.
ldischler, Mar 18 2011
  

       there is no way that sewers connect to the inside if the containment area.
WcW, Mar 18 2011
  

       O/T, but related - My brother mentioned something the otherday akin to this idea. He said, "Do you know why the helicopters are missing their target when dropping water? (they can't fly close enough... due to the radiation)..."Well," he said, "why don't they just put another 200m of line on the bucket?"
Dub, Mar 18 2011
  

       //they can't fly close enough... due to the radiation)//   

       But that's not (as far as I can tell) true anyway. The quoted doserates (though, who knows if they're correct) above the reactors would not pose significant danger to a helicopter pilot who was over them for only a few minutes in total, which could equate to several flights by each pilot. I just think they're being too by-the-book in a very out-of-the-book situation. Either that, or the situation is very different from what we are being told.
MaxwellBuchanan, Mar 18 2011
  

       / there is no way that sewers connect to the inside if the containment area /   

       where does the hot water usually go, then? Probably a dedicated sewer or outflow pipe to the ocean. This is why they put these things close to the ocean: a place to get cool water and get rid off hot water.
bungston, Mar 18 2011
  

       the sanitary sewer system is not used to cool the plant. Under normal conditions in a wet boiler plant the water used in the boiler that "cools" the rods is condensed and re-circulated. This water is "hot" and hopefully never escapes the plant. A second body of water acts as a heat sink. If the container around the rods is damaged by an explosion it no longer functions to condense the steam that is naturally and apparently persistently produced by the rods. This also means that the atmosphere above the rods is not purged of oxygen by steam pressure allowing for H2 explosions. The order of events must have gone something like this IMHO :   

       1)Earthquake   

       2) Turbine shut down   

       3) Circulation pumps fail   

       4) Control rods lowered fully to begin reactor shutdown   

       5) Reactor continues to boil as would be expected   

       6) Leakage somewhere allows pressure out of the core, boiling increases, circulation decreases, air enters.   

       7)Rods, still submerged, are boiling at above safe temperatures (much like a car with a failed radiator cap) and emitting H2. Normally this would bubble safely away in the cooling pool. However the core is now contaminated with Oxygen. Always this is an emergency. Likely all resources to purge the core are immediately used. To little avail, an explosion occurs, likely at the site of the leak. Leak worsens.   

       8) The containment of the core is further damaged. Boiling is now runaway and the levels drop below the top of the rods.   

       9) Rods are now melting. Adding water to the core is a desperate attempt to prevent the core from melting down into a shape that defeats the control rods and leads to an explosion. If the core is kept cold enough it may subside in time. If not it will melt down, and with no additional input explode.   

       We passed the "when will we get this under control" point two days ago. We are solidly in the "this plant is fucked, lead casket and all". Even circulation of water in the plant may not be enough. If the plant is brought under control will find out how many rods melted how much, but conditions may exist in the core at this moment that would make an explosion inevitable. INEVITABLE. Scary thing about exponential processes.
WcW, Mar 19 2011
  

       You should be able to go directly from 1) to 4). Ideally, it takes 4 seconds to scram a bwr, and the earthquake caused reactors 1, 2 and 3 to scram, inserting the control rods (upwards in a bwr) to cease nuclear fission.
Ian Tindale, Mar 19 2011
  

       if the control rods are raised it's a little counter intuitive but so be it. 1-4 seem to have happened at the same time. while it is possible that the pumps had failed before the earthquake it seems more likely that they either could not be powered or that debris in the system clogged them immediately. The fact is that once the rods get hot (atomically and thermally) they self excite to a degree that without effective cooling they will melt themselves. Critical to making an efficient reactor. The other side is that cooling must never ever fail. You must be able to cool the reactor for days, even weeks, before the thing can be considered shut down.
WcW, Mar 19 2011
  

       //while US UAVs observe from above//   

       Hung over operator turns up at the drone centre "Jeez, never seen this part of Afghanistan before..ah whatever." then leans on the fire button looking for somewhere to put the coffee. which would explain all those subsequent explosions...   

       As for the length of the line, looks difficult (see link) and those black Chinooks are just the regular army helicopters, so not a lot of practice with water carrying.   

       As for more major support, like offshore ships/aircraft carrier I'm guessing that it's a possibility that more tsnuamis are expected. The reactor then getting hit by a wave, which is carrying a nuclear powered aircraft carrier, isn't a very appealing prospect.
not_morrison_rm, Mar 19 2011
  

       Why couldn't they splice the power cables. Just hack the plug off on one and splice them?   

       Impure water is p art of the problem, from my understanding.   

       Power plant was guarded against horrific catastrophes, all. Earthquake- backup deisel commits the shut down.   

       Tsunami, internal power acheives the shutdown.   

       Both?
Zimmy, Mar 20 2011
  

       these motors don't plug in. They are massive, with control and starting circuits to match. Starting a motor of this size required that the complete divorced starting circuit is present and that the appropriate voltage phase and current is present. I assume that either the starting circuits were damaged, making starting the pumps using generators impossible, or that all was fine with generators and starting circuits and the pumps were clogged, or obstructed by broken valves, blocked screens etc.
WcW, Mar 20 2011
  

       It was a water pump that needed the power. Perhaps I fail to grasp the scale.
Zimmy, Mar 22 2011
  

       /the sanitary sewer system is not used to cool the plant./ one last thing on this - the rationale behind this idea came from the fact that they were using firehoses and helicopters to splash water around on the outside of these reactors in hopes some of it would go inside then make its way to the right place to be useful. I am sure loads bounced off the sides of the structure and wound up in the shrubbery.   

       Presuming that somewhere inside the building is a sewer line, at least the use of this line would ensure that applied water went into the building, somewhere.
bungston, Mar 23 2011
  
      
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