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Proud Mary

Thu Jan 23 2014, 12:11AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Re-criticality a threat at Fukushima; Concern melted fuel to change itâ€™s form

This was published last month, so the concern over possible 're-criticality' of the corium can't have magically disappeared in life quite as easily as it has from the media.

Notice how all the research into the problem of re-critically will be done in the "future, [when we] will develop the technologies for monitoring and evaluation of sub-criticality in order to prevent re-criticality."

So as yet, no one knows what to do - not even how to monitor and evaluate the risk. This means that whether it blows up or not is at present squarely outside human control. It may blow up, or it may not.

BigBad

Thu Jan 23 2014, 01:24AM

Registered Member #2529 Joined: Thu Dec 10 2009, 02:43AM
Location:
Posts: 600

wrote ...

As far as I'm aware, the only significant radiation from Chernobyl to 'escape into the environment' was airborne pollution from the initial fire, which, as we know, had significant repercussions as far afield as the sheep pastures of Wales. The rest has been pretty much contained.

That was about the worst possible fallout pattern, it rained out over farmland, and then dried into the soil, so it contaminated food chains.

wrote ...

Fukushima, on the other hand, continues to release increasing amounts of radioavtive pollution into the sea and groundwater, with no sign that it will stop increasing for some considerable time.

Yeah, but to a fair degree that's into ocean where it gets fairly thoroughly diluted in a huge mass of water.

I mean, the earth is fairly radioactive anyway; there's a massive amount of background radiation from natural sources, the additional radiation from Fukushima hasn't been very significant, except locally (which is bad enough).

wrote ...

I'd be very surprised if Fukushima hasn't already exceeded Chernobyl regarding radioactive pollution released into the 'wider environment'.

Yes, sure, but it's not been as bad, due to largely fortuitous weather and geography. Still, Japan is fairly polluted now, and there's no reasonable way to decontaminate it.

Patrick

Thu Jan 23 2014, 01:51AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Proud Mary wrote ...

Notice how all the research into the problem of re-critically will be done in the "future, [when we] will develop the technologies for monitoring and evaluation of sub-criticality in order to prevent re-criticality."

So as yet, no one knows what to do - not even how to monitor and evaluate the risk. This means that whether it blows up or not is at present squarely outside human control. It may blow up, or it may not.

It doesnt even need to "blow up" just "re-energize itself" through some means not known to us humans yet, then get 2600C hot again. (very inconveniently.)

unmanned pipe bots and nano/micro ground vehicles will be all thats available even decades into the future. I imagine in my mind, heaps of dead little machines piled up over decades. Abandoned in underground vaults and spaces they were dropped into, after having served humanity.

decontaminating cameras used in the underground Hanford tanks im sure isnt useful...

Proud Mary

Thu Jan 23 2014, 09:36AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Patrick wrote ...

It doesnt even need to "blow up" just "re-energize itself" through some means not known to us humans yet, then get 2600C hot again. (very inconveniently.)

My knowledge of the conditions that must be met for criticality is very small, but we all know that the proximity of two sub-critical masses is one parameter that may be varied to induce criticality - this means that in a heterogenous corium body containing sub-critical masses that factors such as distortion of the body under its own weight resulting from, for example only, compression of the ground beneath, could bring sub-critical regions closer to one another until the criticality condition is met. Cosmic-ray induced fission (used in security applications to scan shipping containers for nuclear materials) would ensure a constant and unending supply of trigger neutrons to keep fission processes alive in the material indefinitely.

The natural nuclear fission reactors discovered in the Oklo uranium mine, Gabon, Africa, expand our understanding of possible corium catastrophe scenarios. The natural nuclear reactor formed when a uranium-rich mineral deposit became inundated with groundwater that acted as a neutron moderator, and a nuclear chain reaction took place. The heat generated from the nuclear fission caused the groundwater to boil away, which slowed or stopped the reaction. After cooling of the mineral deposit, the water returned and the reaction started again. These fission reactions were sustained for hundreds of thousands of years, until a chain reaction could no longer be supported.

Fission of uranium normally produces five known isotopes of the fission-product gas xenon; all five have been found trapped in the remnants of the natural reactor, in varying concentrations. The concentrations of xenon isotopes, found trapped in mineral formations 2 billion years later, make it possible to calculate the specific time intervals of reactor operation: approximately 30 minutes of criticality followed by 2 hours and 30 minutes of cooling down to complete a 3-hour cycle. - Wikipedia

Patrick wrote ...

unmanned pipe bots and nano/micro ground vehicles will be all thats available even decades into the future. I imagine in my mind, heaps of dead little machines piled up over decades. Abandoned in underground vaults and spaces they were dropped into, after having served humanity.

Not just little machines either, as this picture of the vehicle graveyard at Chernobyl proves:

1390469387 543 FT127504 Chernobyl Vehicle Graveyard

Consider the staggering loss of national treasure that abandonment on this scale means. Clearly, though a private company like TEPCO may enjoy the profits of its fission business, the resources of an entire nation are needed to clean up the mess when private enterprise goes wrong. The 'polluter pays' principle can only fail in the face of any Level 7 nuclear accident.

Patrick

Thu Jan 23 2014, 03:58PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Proud Mary wrote ...

Not just little machines either, as this picture of the vehicle graveyard at Chernobyl proves:

yes companies often try to "publi-tize" cost and risk, but of course the profits are entirely private. I was stunned when i started working for Wal-mart, and saw all of my level 5 bosses working 40 hours a week, make more money than i and yet all of them have been on public welfare for at least a 1/3 of their employed years. (i didnt believe any of this from the anti walmart activists --till i saw it, wide and deep with my own eyes, and its not coincidence. its a deliberate business model. ) I dont mean to get political, but the nuclear industry, defense and companies like Wal-mart do this very deliberately.

i hope i get credit for inventing that word...

stop4stuff

Thu Jan 23 2014, 05:29PM

Registered Member #64 Joined: Thu Feb 09 2006, 06:25AM
Location: Southampton, UK
Posts: 68

Thanks for sharing the info you've found out about Fukushima. I've been following this thread for a while and it amazes me that nothing is coming out in UK news.

There's more of the Chernobyl vehicle graveyard at

and more from their homepage

Proud Mary

Thu Jan 23 2014, 09:04PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

stop4stuff wrote ...

Thanks for sharing the info you've found out about Fukushima. I've been following this thread for a while and it amazes me that nothing is coming out in UK news.

You shouldn't be surprised. The UK government has been colluding with the nuclear industry to keep it quiet:

Patrick

Thu Jan 23 2014, 09:48PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Isn't humanity only 2 or 3 million years old?

Proud Mary

Thu Jan 23 2014, 10:42PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Patrick wrote ...

Isn't humanity only 2 or 3 million years old?

The Homo genus of great apes is about 2.4 million years old, but stone tool use begins about a million years earlier.

On this timescale, for modern homo sapiens to create a biocidal global problem like high-level nuclear waste or corium requiring supervision for up to one million years of our future evolution is beyond madness - it shows how disconnected the nuclear dreamers are from the fundamental facts of our life on Earth.

The contracts awarded to private nuclear power companies in the UK only require that they accept responsibility for operating a reactor while the responsibility for cleaning up afterwards reverts back to the public sector. No private companies would bid for nuclear power contracts if they were to be held accountable for clean up costs once the reactor was closed down, and there has been no public dialogue about responsibility beyond a mere 100 years. In March 2012, the total undiscounted cost of decommissioning all present sites was estimated at Â£100 billion, a figure which assumes that there are no more disasters.

The cost of decommissioning a nuclear power station - conveniently ignored:

Patrick

Thu Jan 23 2014, 10:53PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

have you and i discussed the air breathing reactor and its "unwanted episode" proud mary? it seems like we have, but im tired ad my mind is a blur ATM.

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