Molten-salt reactor vs Thorium reactor

I remember a lengthy piece Jan Van Eck wrote on thorium reactors a little while ago and I have to admit, I was fascinated.  Would these be on a par, do you think?

 

https://www.nationalgeographic.com/magazine/2019/03/nuclear-engineer-leslie-dewan-clean-energy-plan/?cmpid=org=ngp::mc=social::src=linkedin::cmp=editorial::add=li20190216ngm-newngmlesliedewancleanenergyplan::rid=&sf207861555=1

 

 

Share this post


Link to post
Share on other sites

(edited)

4 hours ago, Kit Moore said:

I remember a lengthy piece Jan Van Eck wrote on thorium reactors a little while ago and I have to admit, I was fascinated.  Would these be on a par, do you think?

https://www.nationalgeographic.com/magazine/2019/03/nuclear-engineer-leslie-dewan-clean-energy-plan/?cmpid=org=ngp::mc=social::src=linkedin::cmp=editorial::add=li20190216ngm-newngmlesliedewancleanenergyplan::rid=&sf207861555=1

Just to clarify:

AFAIK, molten-salt and thorium are not an "either or" design choice.  Thorium is a fuel.  Molten salt is a moderator and working fluid.  You can mix-and-match fuels & moderators.

To expand on that:
1)   Some fuels:
     a)  Uranium
     b)  Plutonium (byproduct of burning uranium)
     c)  Thorium
2)  Some moderators:
     a)  "Light" water.  I.e. just plain H2O
     b)  "Heavy" water.  Deuterium, an isotope of hydrogen with an extra neutron, is separated from regular water and used as the moderator. 
     c)  Carbon.  Not as effective, but you can build a reactor core with solid fuel and solid moderator.  Makes for a safer design. 
     d)  Molten salt (might require addition of other moderators since it's not as effective)
3)  Some working fluids:
     a)  Light water
     b)  Heavy water
     c)  Molten sodium
     d)  Molten salt
     e)  Helium
     f)  Molten lead

Most reactors currently use light water and uranium.  Those reactors could use plutonium were it legal, and a Scandinavian country is working on mixed uranium/thorium fuel for existing reactors.  Canada uses heavy water reactors.  We reprocess some of our nuclear waste (plutonium) into fuel for Canada's reactors.   At one point, Britain built reactors with uranium as fuel, carbon as moderator, and helium as a working fluid.  South Africa worked on these as well.  Some Soviet submarines use molten lead as working fluid.  Some experimental reactors used molten salt or molten sodium as moderators & working fluid. 

When people talk about "advanced reactors", they're usually talking about different combinations of fuels, moderators, and working fluids packages in different sizes with modern electronic controls and a few neat tricks keeping it stable.  When some entrepreneur claims they have a brilliant new idea, there's usually nothing new or brilliant about it; they've just tweaked existing ideas.  The real question is, "Will the Nuclear Regulatory Commission allow them to do it?"  That's the real crux of the nuclear issue: plenty of nuclear ideas are decades old and obvious, but regulation prevents people from implementing those ideas. 

All that said, the best nuclear idea I've seen is the holos reactor.  There's nothing new or different about the nuclear side of it; it just incorporates a few useful ideas:
1)  100% factory built (cheap to build)
2)  Containerized (cheap to transport)
3)  Meltdown proof (cheap safety systems)
4)  Can follow electrical loads (useful for the most lucrative markets)
5)  Small (cheap financing for end users)
6)  Effectively zero maintenance (cheap to operate)
7)  Built entirely with proven technologies (cheap to develop & obtain regulatory approval)
8 ) Useful for the military (has a lucrative market independent of NRC oversight that can bootstrap its development)

Of course, I'm oversimplifying this, but I do hope these new reactor designs survive.  Realizing their potential for cheap, abundant energy would end oil wars.  Cheap, abundant energy would also make circular economies more feasible.  Between those two things, the major world powers could entirely withdraw from the Middle East and the 3rd world. 

Edited by mthebold
  • Upvote 1

Share this post


Link to post
Share on other sites

You may find instructive an opinion of Michael Shellenberger on molten salt reactors. In essence, you adding chemical complexity on top of nuclear and amount of RA waste is not smaller. Also argues against reprocessing of the spent rods - no shortage of Uranium; no appreciable gain in waste volume reduction and concerns with Plutonium.

Heard him on Mike Alkin's podcast but understand he is quite prolific nuclear advocate (coming from anti-nuclear background) and there are TED Talks with him.

Share this post


Link to post
Share on other sites