On 04/04/2011 09:04 PM, Jörn Nettingsmeier wrote:
On 04/04/2011 08:42 AM, Patrick Shirkey wrote:
On 04/04/2011 04:14 PM, Erik de Castro Lopo
wrote:
Patrick Shirkey wrote:
So just to make sure I am correct here... All
nuclear weapons
require an
assisted explosion?
Yes, you need both high heat and high pressure to force the
fissile
material into the required chain reaction.
So, just having enough Pu-239 in one location is definitely,
categorically not going to be able to cause a nuclear explosion? Not
even a little one that might cause a rapid escalation?
no. and to see how hard it actually is: there were news of a botched
nuclear test in north korea a while ago, where international observers
found evidence of an explosion (by satellite or seismic measurements)
that was vastly less than what was anticipated. such a situation is
called a "fizzle", and what happens is that you bring the two halves
of sub-critical material together too slowly or in the wrong way, and
the chain reaction then heats it up and tears the material apart again
before the entire mass has started to react.
When it comes to news about North Korea who do you trust?
when you pile up too much plutonium or uranium, criticality accidents
can occur, but there is no possibility of an explosion even remotely
comparable to a fission bomb. which is not necessarily a good thing:
iiuc, a good clean atomic bomb test can be more "environmentally
friendly" than a botched one, because a fizzle explosion distributes
the material over a large area and could even lead to greater
contamination than the fallout of a full explosion.
In the case of Fukushima it will be very nice if the whole facility
doesn't go up in a nuclear explosion. 1760 metric tonnes of fuel would
be entirely cataclysmic.
all this information can be found all over the web, in
wikipedia, and
various physics textbooks. for instance, there's a very interesting
anecdote where richard feynman claims he had to show the uranium
processing guys at oak ridge labs how to avoid criticalities (during
the manhattan project) - they had been kept in the dark about this
problem because some nuthead top-brass figured they had no "need to
know". turns out they were keeping large cauldrons of enriched
material lined up against a dry wall, and guess what a second team was
doing on the other side of this wall? yup.
btw, there have been reports cropping up every now and then that
re-criticality incidents have indeed happened in fukushima after the
cold shutdown, either due to overcrowded spent fuel pools or the
melting of one or more core. this was substantiated by traces of very
short-lived decay products that should not have been detectable
anymore if no more chain reactions had occured after the cold shutdown.
this is of course reason to worry, because criticality would pose a
great danger to the crew who has to mop up the mess, due to extremely
high and uncalculable radiation peaks.
but it also shows that criticality != fission explosion.
But what it doesn't prove is that the situation is not getting worse.
And btw, there is not and has not been a cold shutdown of the 4
reactors. They have not got the situation under control and they will
not fix it any time soon. Therefore all the radionuclides that are
spewing out of the earth as the cores work their way down to the mantle
will continue until they cover them up by pouring tonnes of concrete
down the radioactive pits. Until that point there is every possibility
that the situation could get substantially worse with a large "fizzle"
explosion of 870 metric tonnes of melted cores. In the meantime the
Japanese are being subjected to insane amounts of radioactive fallout
and the Pacific ocean is also being polluted beyond belief. It is a
catastrophe of teh like we have never witnessed before.
One idea we are kicking around over here to protect against a massive
explosion or even just the constant explosions that are happening at
this very moment is to create a dome and pump it full of two or three
phase gases/solid mix. Something along the lines of barium infused
concrete with reinforced steel for the dome. Similar to what they use to
create nuclear weapons bunkers. The first layer will be a shell of
concrete and the second will be used to contain the gas/liquid mixture.
The point being that it will buffer against the explosions as the cores
descend into the earths mantle.
i'm as pissed as you at the nuclear industry and current energy
politics (and in fact, it looks like that at least in germany, the
political climate will now finally allow us to retire nuclear energy
for good and fully replace it with renewables).
but spreading vague fear and misinformation is really not helpful at all.
there is a very clear danger, but it's important to get the facts
straight, otherwise it's too easy for proponents of nuclear energy to
re-spin the current outcry into irrational fearmongering - which is
going on alright, but the fact remains that fukushima is a huge
environmental fuckup and the source of much human tragedy.
and if you continue to go on record with perpetuum mobile schemes and
other easily refutable statements, you will not only be wasting your
and other people's time, but also ultimately discredit your vote and
work against your own political ends. (meta-conspiracy theory anyone?)
I don't buy that. There are very real results and experiments of energy
harnessing techniques that are and have been suppressed and shelved by
the mega corps and the military complex. Physics is constantly being
challenged by this fact and the vested interests are well aware of the
threat that such technologies pose to their societal structure. You can
choose to believe that everything is fine in the world and you were
taught everything there is to know about how the universe works. That
won't stop people from figuring out otherwise.
--
Patrick Shirkey
Boost Hardware Ltd.