Um. Hey, if cement was going to work, wouldn't it have been cheaper to just pump cement in the first place?
Nope, not going to work, either. If water flow is reduced here- the pressure, and flow rate, will go up there- making a new leak in a place where the ice was - sort of- working.
Which is why they didn't try cement in the first place. It's a game of whack-a-mole; where the moles dig new holes as fast as you whack. But hey- we're doing something!
http://www3.nhk.or.jp/nhkworld/en/news/20160606_28/
"TEPCO expands ice wall operations at Fukushima
"Tokyo Electric Power Company has expanded operations to create an underground ice wall at the Fukushima Daiichi nuclear plant to stop the volume of contaminated groundwater from increasing."TEPCO on Monday began injecting a liquid refrigerant into more pipes that make up the 1,500-meter wall surrounding 4 damaged reactor buildings. The operation now covers 95 percent of the wall.
"Groundwater flows into the buildings and becomes tainted with radioactive substances. Reducing its volume is a key to decommissioning the reactors.
"The operation started in March on the downstream side of the wall because lowering the water levels too much could cause tainted water to leak from the buildings.
"Workers began freezing the upstream side after making sure there were no leaks.
"The ice wall project still faces challenges. Ground temperatures have not fallen in some places, and groundwater levels outside the wall have not gone down.
"Also on Monday, workers began injecting cement into the ground where temperatures have not fallen."
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Particularly fun is this bit:
"Workers began freezing the upstream side after making sure there were no leaks.
"The ice wall project still faces challenges. Ground temperatures have not fallen in some places, and groundwater levels outside the wall have not gone down."
Translation: They started freezing the other side after making sure there were no leaks. But there are leaks - with no measurable effect on water levels anywhere.................
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6 comments:
I'm guessing about this.
I think they mean making sure there are no leaks in the downstream side has to be done first -- because the ground water level has to stay about where it is around the outside of the plant -- because they don't know how low it can go safely.
Status quo so far has been a combination of ground water flowing through the site around (mostly) the fractured containment, plus cooling water injected into the containment structure and pumped back out (plus some leaking out), all summing up to keeping the hot stuff submerged.
Ideally added cooling water gets pumped back out of the plant and (maybe) cleaned and added to the tank farm, while the groundwater flows around without picking up too much contamination. Nobody knows for sure how much the containment structures are broken, so all that separates water inside from water outside is having the water pressure about equal.
But if they walled off the groundwater coming in on the uphill side, but let the groundwater continue to drain out on the downhill side -- the water level inside the broken containments would have no back pressure and that stuff would all drain out going downhill.
So they don't want to stop the groundwater flowing into the site from uphill -- until they know the site will maintain a stable water level and not drain down from the downhill end once the incoming groundwater is blocked (if it ever is).
And they can't simply trench on the uphill side all the way down to bedrock and build a dam and pump the groundwater around the area and out to sea -- because they're not getting clean water out of the ground on the uphill side of the site --- there's contamination all around the site, I recall reading this a while back.
Handwaving here. It's as close as I get to prayer, I suppose.
Everybody is guessing; they don't really tell the whole truth and nothing but the truth. Way back there- when they were in the middle of the runaway meltdown, they gave up on any previous plans and just started pumping SEAWATER directly onto the reactor core. Corrosive, yes. It's not entirely clear what happened to the water that went in- except it went away. Months later, when they were sure it was "cool" and they had the reactor chamber full of water at least, they finally got a camera to look that the radiation didn't kill immediately - and discovered that far from being full of water, the chamber was something like 9 meters lower than they had been "sure of". ('m guessing on the exact number of meters; but not the fact. No water. And they were still pouring water in, tons per day; and it was disappearing.
Are they still pouring sea water in? They don't say. They ARE pouring some kind of water in every day. Re-using water doesn't seem to be an option, since they keep storing it; and are mostly out of storage space (and the storage leaks).. Cleaning it hasn't worked; and ultimately it's crazy radioactive from tritium, which cannot be cleaned out by any filter or chemical process - you have to use an ultra-centrifuge- not an option.
All we get are these dribbles- and the assurance that everything's fine, nothing to see here... move along...
One thing is clear, it's a mistake to give either TEPCO or the Japanese government any credit for good intentions; they've lied repeatedly, been caught at it- and 3 days later the world is on to the next entertainment.
Hey, what about all that contaminated soil?
How about, oh, using it along the seashore to raise the level of highways and railroads and seawalls?
What could go wrong with that? Cap it with something clean and it'll, um, never go anywhere .....
"Good Lord willing and the sea don't rise ..."
http://www.asahi.com/ajw/articles/AJ201606080056.html
> Re-using water doesn't seem to be an option, since they keep storing it
If they reused the contaminated water, cycling it through the pipes and pumps again, those would end up radioactive as well, and then people couldn't get near them
"All over the polluted zone thousands of workers are busy scraping up the topsoil into large black bags, and only from the air can you appreciate the sheer scale of this operation. So far more than ten million of these bags have been filled. They're then stacked at thousands of separate locations across the contamination zone. ...
...
"As well as the earthworks to raise the town, authorities are building towering seawalls, some more than five storeys high. They're part of a 400 kilometre chain of gigantic tsunami defences being built along the coast of north east Japan...."
http://www.abc.net.au/news/2016-05-24/into-the-zone/7441758
My community is getting smaller. I cannot log on into TAE. I going to miss them.
It's probably a good thing.
I'm out of helpful, useful wisdom.
Jal
All over the polluted zone thousands of workers are busy scraping up the topsoil into large black bags, and only from the air can you appreciate the sheer scale of this operation. So far more than ten million of these bags have been filled. They're then stacked at thousands of separate locations across the contamination zone
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