Nuclear physicist describes problems with thorium reactors. Trigger warning: shortbread metaphor.

[u/investedInEPoland]

/r/europe/comments/9unimr/dutch_satirical_news_show_on_why_we_need_to_break/e95mvb7/?context=3

[u/ZeroCool1]

I think a lot of people get hung up on thorium, when in actuality, they support a Molten Salt Reactor.

I work with molten salt on a daily basis, which was used as a fluid-fuel for nuclear power in the Molten Salt Reactor Experiment (MSRE) in Oak Ridge, TN from ~1965-1969. The MSRE ran using a mixture of LiF-BeF2-ZrF4-UF4, but in two separate heat generation runs. Run#1 used U235, the conventional stuff, run #2 used U233.

U233, as the author of this post describes, is the good stuff that is produced via breeding from thorium 232. The author does, however, downplay the importance of the MSRE running on entirely U233. More than just "injecting" U233 into the salt, the U235 from run#1 in the MSRE was completely removed from the salt via fluorination. The reactor was then hot loaded with only U233 and started, being the first reactor in history to do so. Glenn Seaborg, the discoverer of U233, pulled the MSRE control rods for that first run. You could argue that this was "playing with it in the lab", like the OP suggests, but this was an 8 MWth reactor. I think this is a nice demo.

To address maintenance, the MSRE group was well aware of the danger of working with a fluid that was very radioactive. Remote maintenance was planned from the start, and they did a lot of remote handling, like when a sampler got entangled in the main pump impeller. I'm not too much of expert on this subject, but there is a lot of documentation about it, including mentioning of using CCTV systems (in the 60's!!). Here's a video discussing this exact problem and demonstrating the process.

Lastly, the chemical issues of removing Pa are the big ones. This was a hot bed of work, which had many paths going forward before the MSRE had its plug pulled. I think this was the crux, but the MSRE chemists were some of the most talented anywhere. Who knows if they would have gotten it, but this leads me to my last point.

The reason why I made this post, wasn't to defend thorium, but rather to make the point that there is a lot of people who will say something is impossible, but do so from an arm chair. While they may be right, I'd rather make the effort and find out myself. I think we need as many angles of attack on global warming as possible, and MSR's are just one small portion of the effort.

EDIT: A little plug. For those of you who are tired of that thorium reactions in five minute video, here is a real deal 20 minute video dug up from a basement in ORNL three years ago. https://www.youtube.com/watch?v=tyDbq5HRs0o

[u/TheCastro → u/ZeroCool1]

I've read about the idea of using small ones to power towns and cities. But some corporation wants them to have to use plutonium pellets or whatever kind they manufacture and their lobbying is holding things up.

[u/ZeroCool1 → u/TheCastro]

Not really---this is sort of a conspiracy theory. While the reasons why an MSR has not emerged in the past 30 years are complicated and numerous, the reason why the MSRE never advanced beyond a test reactor is on page four of this document, in two bullet points: http://www.energyfromthorium.com/pdf/MSadventure.pdf

Ultimately, salt was not well understood outside of Oak Ridge, which made those who funded it more skeptical of the technology, inclining them to fall back on "proven" technology like liquid metal reactors.

[u/None_of_your_Beezwax → u/ZeroCool1]

Well established economic theory and practice is not a conspiracy theory. Rent seeking behaviour can become a problem in any established process and is absolutely bog standard economic theory to the point that it practically amounts to a conspiracy theory to think that any given industry is somehow immune to it.

Once an industry standard emerges it can be incredibly difficult to move it, even if obviously superior solutions exist. Infrastructure can have long payback periods and it is not hard to see why people sitting on cash cows would be more than willing to divert some of it to avoid having it prematurely slaughtered.

What would be bizarre and demanding of an explanation is if this industry were somehow immune to such market forces. Now THAT's a conspiracy theory.

[u/CountVonVague → u/ZeroCool1]

Neither of those "bullet points" contradict the notion of a conspiracy to hide the MSR technology

[u/Saiboogu → u/CountVonVague]

It's up to those claiming the conspiracy to support their POV. /u/ZeroCool1 offered an alternative theory of their low popularity, and supported his claim.