If they are uranium based - nay!
Thorium based reactors can't cause a meltdown and if something happens they simply shut off, the reaction is self moderated, and if power goes off or it gets too hot the reaction slows down, unlike unranium based where they need control rods to NOT explode.
A lot of the benefits of the Thorium reactors that are being envisaged are because they are a molten salt design, not because they use Thorium. Molten salt reactors can't cause a meltdown, simply because they are already molten. Traditional reactors have the potential to explode because they are cooled by superheated pressurised water, not because they use Uranium. You can run standard Uranium through a molten salt reactor and get the safety benefits, and you can burn Thorium in more traditional reactors. Likewise, you can make self-regulating reactors that aren't molten salt reactors - it's just that molten salt reactors have one particular really neat mechanism for self-shutdown.
Thorium does have some inherent advantages, two of which are plentiful supply and proliferation resistance.
And conversely, pressurized water reactors, especially older designs are not passively safe, and must go through a cool-down process which requires some of the control systems to be operating properly.
In general I'd like to see more development work in the area of molten-salt reactors, especially those that can reprocess existing nuclear waste.
> Molten salt reactors in general can't cause a meltdown because they are designed to passively moderate in the event of a problem.
At least one design I've seen has a plug in the main salt loop that is made of lead or something with a relatively low melting point. It is actively cooled to keep it solid. If there is a total power failure, and nothing is running, the cooling system shuts off, the plug melts, and the main loop drains out into a containment pool.
The MSR is just running at atmospheric pressure, not super-high pressure like a pressurized water reactor (hence the name). You can crack a pipe, and that's bad, but then the loop will drain out to the containment pool below the reactor. [1]
Unlike a PWR, where cracking a pipe may well lead to a steam explosion. Even if initially contained, this is super bad.
It is unfortunate that many of the reactor designs out there in operation now are not 100% passively safe. Having one or two backup systems (like a Fukushima Daiichi) sometimes just isn't enough.
[1] Now note that recovering from such an emergency reactor shutdown on a MSR is no fun process, and will take a while to do cleanup and get things back up and running. A normal shutdown will not drain into the pool, as I understand it. (Edit: this is wrong, see reply.)
They can also be captured, which gives the enemy the ingredients for a dirty bomb and/or a nice bargaining chip.
My understanding is also that "thorium-based" means U-233 as fuel [1], so that's what would be in the reactor.
Seriously though, from what I read, these can't be used to make weapons, so it's actually a win/win if they get used or stolen.
"In Germany, the story about how Frederick the Great was responsible for bestowing “potato happiness” on his subjects is well known. King of Prussia form 1740 to 1772, he is still referred to as “Alte Fritz” (Old Fritz) to this day. It is said that he ordered soldiers to guard a field of field of potatoes, ostensibly to protect this highly precious crop. Their curiosity aroused, the local farmers, who had up till then showed no interest in cultivating potatoes, stole some of them and started growing them themselves – or so the story goes."
https://www.alumniportal-deutschland.org/en/germany/eating-d...
I don’t know anything about it, but I worry about who is making those safety assessments and what their conflicts and incentives are. It seems like a lot of things can be weaponized or used to nefarious purposes. I can imagine a portable energy source having a lot of potential uses, say powering small sea craft or whatever.
"The concept for the reactors began with the requirement that they would run off of tristructural isotropic particle fuel, or TRISO...Each TRISO particle is made up of a uranium, carbon and oxygen fuel kernel which is encapsulated by three layers of carbon- and ceramic-based materials that prevent the release of radioactive products"
and then further down...
"The fuel has two secondary benefits...the first being its resiliency to proliferation which can help deter the reactors from being targets for bombings or attacks.”
The key advantage seems to be that it can be deployed, turned on, then left to run without refuelling for literally years whereas diesel obviously requires constant refuelling.
The key disadvantage is that IMHO it may be big risk, especially in hostile territory because... well nuclear.
I assume, you will fart in their general direction.
Pretty much everything you say has to do with they type of reactor, and not the fuel. This is a common misconception (perpetuated by some pop-science youtube video stuff).
You can build reactors with different fuels be passively safe. In fact most companies that would like to develop Thorium Breeders are in fact all starting with Uranium reactors but non are not passively save. Terrestrial Energy from Canada for example is party based out of a group that got to know each other at a Thorium conference, yet they are building a Uranium fast reactor. This reactor is passively save and doesn't need 'control rods' to not explode.
Please stop perpetuating this sudo-science.
There is basically s single real benefit to thorium. That is the ability to breed thorium in a thermal spectrum. U-233 that is the actual fissionable material in a thorium reactor generates 2.1 neutors in a thermal spectrum.