On 3/20/2015 9:18 PM, 'Chris de Morsella' via Everything List wrote:
*From:*[email protected] [mailto:[email protected]] *On
Behalf Of *meekerdb
*Sent:* Friday, March 20, 2015 5:20 PM
*To:* [email protected]
*Subject:* Re: TEPCO admits Fukushima Daiichi Unit 1 core completely melted down
On 3/20/2015 10:43 AM, 'Chris de Morsella' via Everything List wrote:
*From:*[email protected]
<mailto:[email protected]>
[mailto:[email protected]] *On Behalf Of *Telmo Menezes
*Sent:* Friday, March 20, 2015 10:32 AM
*To:* [email protected]
<mailto:[email protected]>
*Subject:* Re: TEPCO admits Fukushima Daiichi Unit 1 core completely melted
down
On Fri, Mar 20, 2015 at 6:20 PM, 'Chris de Morsella' via Everything List
<[email protected]
<mailto:[email protected]>> wrote:
http://www.beyondnuclear.org/japan/2015/3/19/tepco-admits-fukushima-daiichi-unit-1-core-completely-melted.html
Just in case anybody wanted to pretend that the Fukushima disaster is
behind us;
here is this piece of bad news, based on recent telemetry using muon
detectors for
imaging the reactor vessels. The core of reactor units 1 appears to have
melted
through both the reactor itself and the outer containment structure. This
is also
the likely situation for units 2 and 3 as well. A total meltdown is not a
good
scenario – and that is a huge understatement.
It sounds bad for sure.
What can the consequences be?
They cannot be good, that is for sure. If the cores of units 1,2, and 3
have melted
all the way through the outer containment structures that implies that the
radioactive materials that had been contained in those cores has now
migrated into
the ground beneath these units. I would imagine that the intensely hot
corium, at
first melted down in a tendril like manner forming a branching structure
until it
becomes diluted with enough melted rock to decrease the intense
temperatures. At
some point – I would imagine – it would become dilute enough so that it no
longer is
above the temperature required to melt rock and at this point it will
become fixed
into the sub surface geology beneath those plants.
As ground water comes into contact with this highly radioactive materials,
it will
continuously leach some of the content and transport this radioactive
material
elsewhere, including into the Pacific ocean and underlying aquifers.
I believe that this is the prime motivation for the – desperate – attempt
to create
a sub-surface wall of frozen ice around the affected area to try to contain
this
radioactive hell within the ice wall so that it does not migrate into the
larger
surrounding environment.
I have no idea how one could go about trying to remediate this; how would
one go
after the concentrated tendrils of dilute corium that has become frozen in
place in
the surrounding rock matrix. A first step would be to get a better idea of
the
3-dimensional sub-surface distribution of the highly radioactive material,
in order
to at least begin to get an idea of the scope of the problem.
-Chris
I'd guess the best solution is: Don't mess with it and see that nobody else messes with
it. Just keep monitoring food and water. The corium should all be solidified into a
glassy mass by now and not very susceptible to dissolution in water.
I agree the branching like glassy mass of the corium/rock mix is probably best left in
place. However I also believe that it is incumbent – and this is a long haul effort of
many decades and perhaps centuries – to isolate the very hot sub-surface glassified
branching structures of solidified corium melt/rock mix from the larger environment. As
you noted glass is not **very** susceptible to dissolution in water. However glass is
not immune to leeching what is contained within the glass mass – slowly – into water
that it comes into contact with. Water is an excellent solvent.
The ice wall though flawed is a necessary first start. Apparently this reactor complex
had been sited over an area with substantial subterranean water migration going on, not
the best place to put a reactor over (nor was it wise to site it in a tsunami zone
either). The ice wall’s aim is to form a barrier that diverts the flow of water around
the Fukushima complex. If they can also clear – using hardened robots, because there is
some very hot debris still covering the site and especially within the damaged
structures themselves – if they can clear away all debris and cover the surface with
impermeable covering in order divert runoff away from the site. And they then pump away
the water table from below the hot zone; then this hot zone could in principal become
isolated from water, which is the major carrier of stuff in our environment.. and hence
largely isolated form the rest of Earth’s living systems and biosphere. A wall made of
ice is an emergency measure. Eventually they will need to trench and trench very deeply
around the hot zone and back fill those trenches with something very impermeable like
compressed bentonite; perhaps even well injecting high pressure concrete mixes into even
deeper areas beneath the trench in order to get the barrier to intersect even deep zones
of water movement.
This is a massive engineering undertaking! Many times the mass of the great pyramids
will need to be moved. Which is why getting the best picture of where the radioactive
stuff has ended up is important so that the job can be correctly scoped and only what is
absolutely necessary can be walled in from the rest of the earth.
If the hot areas can be kept from contact with water they will remain contained, and for
as long as they are kept out of contact with moving water will continue to remain
contained within the surrounding mass of earth and rock.
Chris
I think you're over reacting. Is there any evidence that corium products are showing up
in ground water or the ocean? It isn't necessary to keep the corium from leaching into the
ocean; only to make it slow enough so it becomes so diluted as to be indistinguishable
from background. So far I don't think any corium products have been detected in the water
table or in the ocean around Fukushima. The cesium 134 found is from the initial
explosion and run off.
https://www.whoi.edu/page.do?pid=83397&cl=101673&tid=5122
http://www.ourradioactiveocean.org/results.html
Brent
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