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Author: Subject: Molten Thorium Salt Breeder Reactors - a discussion
j_sum1
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[*] posted on 21-9-2017 at 04:47
Molten Thorium Salt Breeder Reactors - a discussion


https://www.youtube.com/watch?v=c7baTdyHv8g

This video came over my YT feed and I watched it and a couple of others like it.
It hails loudly the potential benefits of breeder reactors and thorium. More specifically than that it promotes a reactor design where the coolant is liquid fluoride salts, the fuel is thorium(IV) contained within the coolant (I think) and the reaction is moderated by graphite.

Parts of the video smack of conspiracy theory tripe that a technology developed post war was suppressed by the powers of government and now the Chinese are furiously advancing a technology abandoned by the West.

A number of benefits are stated or implied:
  • fuel source about 400 times as abundant as U235 and already easily obtainable from current mining operations
  • non-fissile fuel that cannot be diverted to weapons
  • no pressurised coolant (which has been the main danger associated with the various nuclear disasters we have incurred thus far)
  • No incidental H2 produced by bombardment of water molecules
  • No degradation of fuel rods by reaction with hydrogen
  • Efficient harvesting of nuclear energy with several steps of the nuclear reaction chain involved
  • Safer, less radioactive fuel material
  • Safer, less voluminous and less radioactive waste stream
  • Utilisation of lower energy thermal neutrons to sustain the reaction
  • Negative feedback inherent within the system such that the reaction slows if the reactor becomes too hot
  • A simple, mechanical, gravity-powered drain system that removes the liquid fuel from the moderator and automatically quenches the reaction in the case of failure


Not mentioned in this video and not explained in others I watched is a "kidney" system for processing and replenishing the coolant/fuel and diverting the reaction waste products. From a chemistry point of view this sounds interesting but I have not yet found details.


I guess my question is how much of this is over-stated hype? How much is feasible? What are the things that have been misrepresented in this presentation?
(Something very easy to do with this kind of edited stream.) And what difficulties, problems, engineering challenges or potential disasters have been glossed over or omitted?

Is this something that should be getting a lot more air-time than it is?
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[*] posted on 21-9-2017 at 11:30


I have nothing against Thorium, and in the long run it does sound like a better choice. But do we really need Th to produce clean, safe energy?
We already have good reactor designs (at least far better than Chernobyl and Fukoshima), what we're lacking is breeders that can utilize more of the fuel.

Even if we were to conclude that fission is a lost cause, wouldn't a breeder be the best way to reprocess the current stockpile of spent fuel?




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[*] posted on 22-9-2017 at 15:57


So what you are saying is that we could easily invest in current safe technologies without having to develop a more novel technology?


I hadn't come across the liquid fuel concept before. I am interested to know how much of what I have recently discovered is hyperbole. And I am intrigued to know more details about the so-called "kidney" process -- the chemical side of things.
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[*] posted on 22-9-2017 at 21:29


ask tony abbott about the idea j_sum



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[*] posted on 23-9-2017 at 00:17


One can always chase after newer and better technologies, but these take decades to develop and implement. In the mean time we're still relying on 1. generation plants or fossil fuels.
None of the newer designs can solve the real problem with nuclear reactors either: Radiation and complexity. No matter which technology we pursue accidents are bound to happen, and they will release radiation to the surrounding areas. And even with less waste there will still be challenges with handling and storage. But if the alternative is global warming, what choice do we have?

Lets face it: Chernobyl and Fukushima were disasters for us, but not really for the planet. Within a few years these places turn into wildlife sanctuaries where life flourishes like never before.




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[*] posted on 23-9-2017 at 15:36


I don't dispute that thorium is a potentially better source of fission and for producing cleaner energy.
But the underlying issue is the fact that thorium must be irradiated with neutron before it can be used as fuel.
As we all know.

I think the main and perhaps only reason why we haven't seen breeder reactors used in industial energy production is because its far far too easy for someone to simply swap out that thorium for some uranium and start producing weapons grade fuel from it.

If we were to hand out permits to lots of companies to run their own breeders then im sure most would stick to the rules and just run them for energy production.
But there is always that problem of some reactors being used to make plutonium, even if not within the united states but in other countries such as india or iran or something, which i think is why is has been suppressed.

Taking breeder reactors in general out of the research level and placing them into the industrial level is just too dangerous for fear of clandestine use.

Molten salt also has one other disadvantage, in that the molten salt cannot be allowed to solidify within the reactor, presenting a problem when changing out fuel.
We could by all means do it, but it would make things a hell of a lot more difficult.

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