Dark Matter evidence found at Chicago not HLC: 12/18/09

tullio
tullio
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RE: The concepts behind

Message 96141 in response to message 96140

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The concepts behind ITER are pretty well established, really. A reactor of its kind has simply never been built at that scale before, which does of course pose some impressive engineering challenges. It will also be the first fusion reactor to -produce- energy - the previous best has been to break even, I believe.


AFAIK ITER is only a proof of concept and shall not produce electrical energy, only I4 MeV neutrons. Then you must use them to boil some water and produce some vapor. Unfortunately the vessel containing the water shall become radioactive in a short time and then suffer what in fission reactors is called "swelling". Then you must substitute it and dispose of a radioactive container. It is simply not true that fusion reactors do not produce any radioactive waste. They also use tritium, which is radioactive and, if inhaled as a vapor, will produce lung cancer.I have played with neutrons in my youth and, being neutral, you cannot detect them with a Geiger counter or a ionization chamber like you do with charged particles. Very nasty beasts, the neutrons are.
Tullio

Chipper Q
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RE: RE: The impression I

Message 96142 in response to message 96135

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The impression I get from the mainstream media and literature from policy makers is that they are looking for an end result.

Speaking of end results, I wonder where fusion reactors are at these days? Now that's an area well worth plugging at, for some benefit. With a similiar level of material investment that 'big science' has. Last I heard they had not achieved technical 'break even' rates - a net output of energy - and way off anything economically feasible. Yet. They need to 'surf' the plasma for longer.

Cheers, Mike.


This is from PhysicsWorld, last December – Fusion Challenges and Solutions – it's an 8 MB pdf file. It's worth checking out just to see the advertisements – not sure what I'd do with an Emittance/Phase Space Scanner, yet, but it's nice to know one is available should the need arise :)

As near/far as I can tell, it looks like a controlled/sustained output is still just too hot to handle – but since the job can also now be done with photons, well, that looks like a bright way to go about it!

tullio
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Fusion research is still

Fusion research is still Physics research, not yet nuclear engineering. Enrico Fermi was able to light a bulb with electricity produced by the first nuclear fission reactor, his Atomic Pile in Chicago.ITER is still away from it. As a former Bull Italy employee I am glad to see that Bull is taking part in this Big Science project.
Tullio

Rod
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Because of the engineering

Because of the engineering complexities with regard to fusion, It is pie in the sky for a intermediate future. Spending a lot of money on proof of concept at this stage, I think, (not a waste of money) just not a wise use of resources.
I have the following conference just 150Km from my house.. I am looking forward to it. (Just to Check it out)

Electrical Power and Energy Conference

There are some who can live without wild things and some who cannot. - Aldo Leopold

tullio
tullio
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Canada has built its own type

Canada has built its own type of fission reactors, the CANDU series, using natural uranium as a fuel and heavy water as moderator. Now they have a new design, the ACR-1000.
Tullio

Rod
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RE: Canada has built its

Message 96146 in response to message 96145

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Canada has built its own type of fission reactors, the CANDU series, using natural uranium as a fuel and heavy water as moderator. Now they have a new design, the ACR-1000.
Tullio

The ACR-1000, I doubt if it will ever be built. My province(pop: 140,000) is part owner in a one reactor vessel CANDU. It is currently undergoing an expensive refurbishment. We have the highest electrical rates in Canada at 13.65 cents per Kilowatt/Hour. The Canadian Dollar and American Dollar are at par.

edit: It looks like we are going to loose the distinction of being the highest to 'Ontario'

There are some who can live without wild things and some who cannot. - Aldo Leopold

tullio
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RE: The ACR-1000, I doubt

Message 96147 in response to message 96146

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The ACR-1000, I doubt if it will ever be built. My province(pop: 140,000) is part owner in a one reactor vessel CANDU. It is currently undergoing an expensive refurbishment. We have the highest electrical rates in Canada at 13.65 cents per Kilowatt/Hour. The Canadian Dollar and American Dollar are at par.

edit: It looks like we are going to loose the distinction of being the highest to 'Ontario'


Well, I am paying 19 eurocents/kWh that is about 26 US cents. That because our electricity is provided by thermal power stations fueled with methane.All nuclear development was stopped in 1987 after a referendum. A 40 MWe nuclear reactor, CIRENE, very similar to CANDU, was never started. It had been designed by prof. Mario Silvestri of Milan Polytechnic. He asked to be authorized to test at least its softare but he was not allowed. He died soon after.
Tullio
PS I had known him personally, he was one of my advisors at Edizioni Scientifiche Mondadori. He was also an historian. One of his books was "Isonzo 1917" which described the causes of the catastrophic defeat of the Italian Army at Caporetto (Koparid) in the First World War.But probably "A farewell to arms" by Ernest Hemingway, which describes the same event, is more know outside Italy.

Mike Hewson
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Fusion does produce

Fusion does produce radioactive remains, but there are key differences compared with fission processes :

- tritium is produced ( as that's what hydrogen/deuterium is generally fused to ) but in masses/amounts far less than fissile waste. Half life is about 12 years and is a beta emitter. Dangerous in the 'short term' if you're nearby, but is readily shielded - thick cardboard will stop beta emission. The main health trouble thus would be inhalation/ingestion. Decays to stable Helium 3.

- the containing vessels are induced to be radioactive, primarily by isotope production on receipt of a neutron. The half lives generally aren't comparable with the high mass radioactive metals - many measured in fractions of a second or minutes compared to multi-years. See here. But of course you'd still need to isolate the remains of the reactor ...... so quite rightly it's not the sort of thing that people want in their backyard.

If you look at this curve you will see the energy 'value' returned for given transitions. A good fraction is just in going from hydrogen ( one proton ) to Helium alone. Which is why the Sun is so hot. Whereas all the mucking about at the high atomic mass end, iron and above, requires large amounts ( relatively ) to get an equivalent output. Roughly :

[ fusion with high energy per nucleon x smaller number of nucleons ] vs [ fission with low energy per nucleon x larger number of nucleons ]

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Note : nucleon means a proton or a neutron, whereas a nuclide/nucleus is a bunch of them


this is what makes fusion more alluring, and fission ever so problematic. If only we could get it to happen on Earth, or as Tullio rightly points out - why aren't we using the free stuff delivered regularly everyday, at the crack of dawn. Put that way, it is a no-brainer really, or thus : why are we so stupid to not take every advantage of that?

Cheers, Mike.

( edit ) One might ask where did the high end metals come from if not energetically favourable via fusion in stars? Supernovae produce them, from the
kinetic energy of imploding stellar cores.

Another way of thinking of nucleons is : suppose I am to give you 1000 nucleons in any form you want. What could you choose? I'd suggest taking them as hydrogen nuclides for the above reasons, yielding say 5 Mev per nucleon in transitions ( 5000 Mev the lot ). Whereas if you chose say Uranium, you'd only get about 4 atoms worth with a rather lower rate of return ( about 1 Mev per nucleon, so 1000 Mev for the bunch ) when fissioning down to lead/iron etc.

( edit ) The binding energy per nucleon curve is key to understanding many processes. If one looks at progressive fusion in older stars, they relatively rapidly burn the higher mass ( but lower than iron ) nuclides in the twilight of their lives. So they may spends billions of years on the main sequence doing hydrogen/helium processing - but only spend months, days and hours with some elements beyond Silicon ( atomic mass 30+ ) say. There's only small 'profit' in those reactions, the core can't be held up, gravitational contraction occurs ....

Sometimes the binding energy curve is flipped over to show energies as negative ( emphasising the binding aspect ), in which case iron ( or a particular isotope of cobalt actually ) is at the very bottom of the pit.

( edit ) Whoops. Nickel-62 has the most binding energy/nucleon ...

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

tullio
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In the small town near Milano

In the small town near Milano where I live they are building condos with solar panel on their roofs, both thermal and photovoltaic, and air conditioning coming from the ground. I think there is a European law saying that from 2020 all new buildings must be selfsufficient in energy terms. This is a way to reduce both imports of methane gas from Russia and air pollution.
Tullio

tullio
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According to New Scientist

According to New Scientist the Xenon liquid detector at the Gran Sasso Laboratory shows no sign of dark matter.
Tullio

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