[warfangle]

>You're confusing issues from pressurized reactors with LFTRs.

Nope, pretty sure I'm not. I'm well aware that LFTRs run at low (even sub-atmosphere) pressures.

>We built and ran LFTRs commercially in the 1950s in New York State and Pennsylvania

We never ran LFTRs commercially. If you know otherwise, please cite. I only know of two experimental reactors at the Oak Ridge facility: the Aircraft Reactor Experiment and the Molten-Salt Reactor Experiment.

> I don't know where you got that idea.

I got that idea from some pretty simple facts about nickel alloys (like Hastelloy N) under neutron bombardment.

When you bombard nickel with neutrons, you produce helium. When the helium builds up irregularly, the alloy becomes brittle. You can dope Hastelloy N with titanium or niobium to even out the distribution of helium deposits (this is what ORNL did) but that brings the maximum temperature down to 650C.

As well, tellurium (one of the fission products of a LFTR reactor) corrodes the grain boundaries of Hastelloy N. You can reduce this effect by doping it with niobium and keeping the UF4/UF3 ratio to less than 60.

You have to trade off lower temperatures with whether or not you want to deal with beryllium toxicity. You can replace BeF2 with a eutectic lithium fluoride/thorium fluoride composition, but that requires an increased temperature of the reactor salts. There are other problems with using beryllium, though - it produces lithium-6, which is a strong neutron poison.

You also have to filter out noble element deposits, because they don't form fluorides.

There are also serious design challenges with modifying current turbines to work with supercritical CO2 or helium. You can use supercritical steam instead, but it isn't nearly as efficient.

You also have to worry about tritium diffusion. It's small enough that it leaks through the heat exchangers.

There are issues with the rapid expansion/contraction the graphite moderator, but some are working on graphite pebble designs.

Once you throw the corrosive salts, strange reaction byproducts, and neutron bombardment into the mix, I highly doubt that 'the average body shop' could pull off the fabrication of a LFTR style molten salt reactor that could run safely for longer than a week.

[Gravityloss]

I was surprised to hear from GE that a CO2 working fluid power plant using turbine waste heat is a thing nowadays. They have a contractor, Echogen, who provides that part.

http://www.cospp.com/articles/print/volume-14/issue-01/featu...

http://www.echogen.com/documents/why-sco2-can-displace-steam...

In ships, when fuel costs just keep on rising, that starts making sense. (There are other reasons why it might not be good though.) On land power plants, it might make natural gas electricity more competitive against coal with this better efficiency.

Though I don't see the keyword supercritical on the Echogen site yet...

[warfangle]

Oh neat, I didn't know about that either.

[JohnHaugeland]

You are quoting verbatim as fact from an unsourced blog post you provide in another comment. That blog post says what you're claiming as fact are /rumors/. It points out beside the issue things like that a heat generation experiment that wasn't hooked up to dynamos didn't generate electricity, in literally the same paragraph as claiming they produced too much heat (so use some of it?)

In the meantime, it refers to hypotheticals as its only criticisms, many of which are mutually contradictory, many in ways as obvious as the above.

On top of that, one of the best bullshit detectors that has ever existed is watching for basic quality of language, and this guy has not yet mastered the wily apostrophe.

With apologies, I'm not going to be your unpaid research assistant tonight. You made a claim without evidence. I dismissed it without evidence. You seem to believe the burden of proof is now on me. Sorry; I have other things to do which are more important to me, and you flat out ignored several of the things I said, so I'm comfortable doing the same (like when you claimed that building ceramic housings was a challenge, and I thought you were confused about Japan Steelworks; you have provided no explanation for believing that ceramic containers, which Hitachi uses extensively, are out of our reach.)

Similarly, your story about grain boundaries is compelling, at least if you don't consider lining the reactor. But then you go on to observe that a 50s reactor ran for four years without a problem on 50s metallurgy, and don't seem to think that that's a problem for your concern.

Finally, that's true, you don't want to be around irradiated fluorine. But if you would rather be near a failed coal plant than a failed lftr, my interpretation is that you don't know much about what happens in either a fluorine leak or a coal plant explosion. Fluorinated uranium rain two countries away? Buddy, not even six blocks away. What makes that shit dangerous is how violently and universally it reacts. There would be less uranium and fluorine in the rain than in to day's seawater.

Helen Caldicott off, please. Either do the envelope math or stop pretending it's anything more than blog fuelled FUD.

[warfangle]

> You made a claim without evidence

So did you :)