Tuesday, August 22, 2017

The Ice Wall Update-eth

Another bit of PR from the ice wall people; they've been coming about one a day for several days now.

This one has a nice video, which I hope you will be able to access for some time; NHK has recently added the ability to share their news posts with several social media.  I'm hoping that means their links will last more than one day.

The video has good diagrams, and even real footage of the ice wall apparatus; good to help understand.  Take a look-

Typically for NHK, the printed text is almost exactly the same as what the newsreader presents, quoted below, then I have a couple comments on the hydraulics/physics after that:

"Fukushima ice wall's last section being frozen

Final procedures have begun to complete an ice wall to prevent groundwater from entering the contaminated Fukushima Daiichi nuclear power plant.  Tokyo Electric Power Company workers started the process to freeze the remaining 7-meter section of the ice wall on Tuesday.  They opened 11 valves to allow coolant at a temperature of minus 30 degrees Celsius to circulate in the underground pipes.

TEPCO began freezing the 1.5 kilometer long wall in March of last year. The last section on the mountain side of the facility had been left unfrozen as officials said the move could cause a sudden drop in groundwater levels around the reactor buildings.  But the Nuclear Regulation Authority said safety measures were in place and gave permission for the procedure earlier this month.

TEPCO says it could take longer than the 2 months projected based on past records for the section to freeze, because the groundwater is flowing at a rapid rate.

They say once the wall is completed, the volume of groundwater flowing into the reactor buildings will be reduced to less than 100 tons a day, from the current 140 tons.  The nuclear regulators say they will carefully monitor the effectiveness of the wall.

In good PR fashion, they are setting the stage for it to - not work.  "It could take longer..."

And; the physics: so, the ground water is flowing - IN - at a rapid rate?  That does mean - it has to be also flowing OUT - somewhere, somehow - at a rapid rate.  Which means if/when you shut the flow off, there WILL be increased pressure on the 'up' side - and decreased pressure on the 'down' side; which means the pressure gradient will be increased.

The pressure on the upside is the easiest to understand, but actually the entire gradient is a better predictor of the likelihood of new leaks.  Think of it as more "incentive" for the water to find a new way to move.

Other Japanese news sources include more definite doubts:

"But some experts have cast doubt on the ice wall, and the country's Nuclear Regulation Authority said it has not yet done an independent analysis.

" 'We doubt the ice wall is going to be as effective as TEPCO claims it will be," said an NRA official who spoke on condition of anonymity. 'We're going to monitor its progress after it is finished to check the impact. ' "

"In June, the NRA's acting chief Toyoshi Fuketa publicly accused TEPCO of lying about the wall's effectiveness."

Ice wall cost so far admitted to: ~ $320 million; paid by the "government"; i.e. Japanese taxpayers.

Monday, August 21, 2017

The Ice Wall Leaketh

Back in March, 2016, I put up this post about the proposed "ice wall" to prevent water movement in bad places around the nuclear reactor melt-down site at Fukushima, Japan.

It won't work, I said.  By one sensible measure, I can claim to have been correct already; in the news release cited there the "authorities" stated "The wall is expected to start restricting the inflow of groundwater about 45 days after the freezing starts."  And be finished in 4 months.

Here we are, not 45 days but 17 months after they started freezing - and - the wall is not closed.  It still leaks 140 tons of water a day.

The whole episode is a fabulous lesson in how to spin information for public consumption.  Today's press release, that they are "about to start the final phase of the freezing process" - states that "a 7 meter section has been left unfrozen" - implying that they intended to leave it unfrozen, for various arcane, scientific, and benevolent reasons.  That is not the case.  They were unable to freeze it.  Which is just what I predicted from my modest understanding of hydrology and fluid dynamics (I thought that any good ecologist should be familiar with environmental forces; like rivers, ocean currents, jet streams; so, I studied them.)

Reality back there was they were very unhappy and embarrassed that some of the wall refused to freeze, and they had to "study" to determine "why"; eventually coming up with the obvious- the water in those areas was flowing so fast it never got cold enough to freeze; and the high flow rate kept re-warming the soil.

Most of us have personal experience with this principle of hydraulics; water under pressure, when forced to flow through a smaller channel, will flow faster.  And it's very powerful.  Ever have a running garden hose in your hand? Ever put your thumb over the open end- maybe to make it squirt your little brother, who thought he was a safe distance away from you?  It'll really squirt.  Because when you restrict it, the pressure in the immediate area of the constriction- goes way up; and the smaller stream flows much faster.

And- when you tried to totally shut off the flow, using just your thumb; you couldn't do it.  The pressure simply builds higher, until it finds a way through your block.  Powerful stuff, water.

So they've had well over a year to figure out how to freeze the high flow area.  It's not impossible they may have figured out a way to shut off what has to be an enormous stream of ground water, with potentially very high pressure and flow.  It can probably be done.  They could make the refrigerant there much, much colder.  Or, they could build an arc of more refrigeration upstream of the leak, so the water reaching the leak is just about to freeze when it gets there.

And if they succeed in shutting that 7 meter leak- what will happen?

100% - other places in the wall; not currently leaking; will start to leak.  As a little leak starts, it will warm the area from the warmth in the water, and it will become a BIG leak; since the local pressure there is now higher than when it wasn't leaking.  Shut that leak?  Another will start.

Check my prediction; in another year.  I'm betting - 100%.  And ANY physics professor should have been able to tell them this.  So why do it?  They have to appear to be doing something - and they have no clue what might actually be useful.  None.  But they're spending hundreds of millions of dollars - so it has to be worthwhile, right?  It is for the contractors, I guarantee.

Below is the text from the NHK press release.  If you search this blog for "ice wall" there are multiple additional posts on this debacle, with more facts.

"Work to finish ice wall at crippled plant to begin

"The operator of the crippled Fukushima Daiichi nuclear plant will begin the final phase of creating an underground ice wall on Tuesday. Tokyo Electric Power Company started the work 17 months ago, with the aim of preventing groundwater from entering reactor buildings and getting contaminated with radioactive substances.

"The 1.5-kilometer ice barrier is deemed a key step to curb the buildup of tainted water at the plant.

"The soil is frozen by sending liquid at minus 30 degrees Celsius into pipes buried around the buildings. But the utility has left a 7-meter section unfrozen, fearing the sudden fall in groundwater levels around the buildings. There were concerns that the difference of water levels in and outside the reactor buildings would cause tainted water inside to leak out.

"But last Tuesday, the Nuclear Regulation Authority said safety measures are ready and gave its approval to freeze of the final section.  Officials of the utility say they will carefully monitor the freezing process of the remaining section.

"They say it may take longer to fully freeze than other areas, because the flow of groundwater has been concentrated in that section.

"The officials expect that the wall, when completed, will reduce the inflow of groundwater to the buildings from 140 tons a day to less than 100 tons."