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42 comments on On the hazards of ignorance of thermodynamics

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BobE on October 8, 2008 - 5:41am Permalink | Subthread | Parent | Comments top

Helium has very nice thermodynamic properties for heat transfer. But what about Peak Helium?

http://www.energybulletin.net/node/34563

BobE

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fluffy on October 8, 2008 - 5:51am Permalink | Subthread | Parent | Comments top

Is there any particular reason that Neon or Argon could not be used instead? (Neutron activation?)

In any case, technically a nuclear reactor should produce helium as a by product, although goodness knws how you'd go about capturing it..

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DIYer on October 8, 2008 - 6:32am Permalink | Subthread | Parent | Comments top

Argon isn't quite as good. The heavier the atom, the poorer the heat transfer characteristics of the gas. I don't think Argon has much of a neutron cross section, but I'd be guessing on that.

It does make argon useful in those insulating windows, though :)

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wkwillis on October 10, 2008 - 1:09am Permalink | Subthread | Parent | Comments top

Cryogenic plants for Oxygen and Nitrogen produce Argon, Neon, Krypton, Xenon, and Helium, in that order. Argon has a high thermal neutron absorbtion, like Nitrogen, but is widely available. Neon has a low thermal neutron absorbtion, and is available but scarcer. For Fast Neutron Gas Cooled Reactors, Argon is perfectly acceptable and we aren't about to run out.
If we have carbon sequestration rules, then there is also going to be a good deal of byproduct Neon arriving for Pebble Bed Thermal Neutron Gas Cooled Reactors.
Since we have a limited production capability for Pressurised Water Thermal Neutron reactor pressure vessals, the only quick reactor ramp up is going to be Fast Neutron Gas Cooled Reactors. Pebble Bed Thermal Neutron Gas Cooled Reactors don't have to worry so much about pressure surges, so the pressure vessal is simpler and cheaper to build.

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Engineer-Poet on October 10, 2008 - 10:42pm Permalink | Subthread | Parent | Comments top

Thermal-neutron molten salt reactors might be even faster to build than gas-cooled, because the fuel cycle might be started with plutonium from spent PWR fuel instead of enriching raw uranium.  MSR's don't merely dispense with forged reactor vessels, they operate at atmospheric pressure.

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wimbi on October 8, 2008 - 7:57am Permalink | Subthread | Parent | Comments top

Right. that's why, when I think of ways to save the world for heat engines after TSHTF, I restrict myself to nitrogen- (separated air ), or hydrogen (separated water) as the only sane choices for working fluid. Nitrogen is sluggish but ok, and hydrogen is just great, but has bad habits re alloys and such. So, nitrogen. Then you have a big sort of ugly engine, but works well enough. I am talking about the one you put on a tractor train to haul all the neighbors into town for the week end party, using moldy hay as fuel.

Truth of it is that I still can't beat a plain old IC engine running on a wood gasifier. Anybody can do it. Does not take any superannuated dreamers like me.

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Engineer-Poet on October 8, 2008 - 9:13am Permalink | Subthread | Parent | Comments top

Hydrogen is a great coolant, but it reacts with graphite and causes hydrogen embrittlement in metals.

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42 comments on On the hazards of ignorance of thermodynamics

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