They don't produce plutonium. Department of War (later the Dept of Energy) had a LFTR (liquid fluoride thorium reactor) running at Oak Ridge but the primary goal there was to produce plutonium for the military's nuclear weapons arsenal, not electricity.
In addition to having a far more plentiful fuel source, a LFTR runs at ambient atmospheric pressure so it's not necessary to have a massive containment dome surrounding the reactor in case of a core loop breach. Also, the chemistry of a LFTR tolerates the addition of partially spent uranium fuel (popularly mislabeled as "nuclear waste") which is then consumed in the normal fuel lifecycle of a LFTR. Why this wonder of chemistry isn't more commonly known is beyond me: we could simply solve the Yucca Mountain problem by recycling the partially spent fuel stored there into liquid metal reactors like the LFTRs. The downside is that if you have to scram a LFTR the core chemistry solidifies (it's liquid metal, after all) and restarting is time and energy intensive.
Ultimately, though, because the LFTR didn't produce plutonium for bombs the Department of Defense didn't have interest in running it.
I disagree with this. 233U is part of the Th cycle. You definitely get transuranic elements out, though admittedly less. There is an advantage though, you can produce power and pull out enriched uranium while doing that; an enticement plant that generates power. (Note: we already use reactors that have low plutonium yields)
The real reason that we don't have thorium reactors is that it's difficult. All the kinks aren't worked out. Compound that with that it's hard to implement new reactor designs and the process becomes really slow to work out those kinks.
The answer, unsurprisingly is extremely complicated but certainly isn't just because it doesn't produce Pu, or rather creates low yields. This myth needs to die.
I think it's fair to say our expertise in Uranium cycle fuel came out of the fact it generates substantially more plutonium for nuclear weapons. This was a huge reason it was selected over Thorium initially. Now, it may just be momentum. I argue it's because back in the day, it didn't product Pu.
Also keep in mind that the Uranium cycle is SIGNIFICANTLY easier. I'd argue that that played a major role. But I'm also not denying that weapons didn't play a role.
The fact that as a total percentage of the cost of generating the power Uranium is cheap as heck. All of these complex alternative fuel plans are solving a problem that doesn't currently exist.
If we went all in with fission we still have thousands of years before it's an issue, by which point we'll probably have figured out some even better alternatives.
Oh dear this ancient repeated never ending debate. Nuclear lost - in cost, in failure modes, in lack of private funding, in plant build time, in risk of enrichment systems... dead horse is dead.
Edit. Add the fact the reactors take decades to develop, cool story we have about ten of those decades before really shit has hit irreversible climate destabilization fan.
Tell that to the US Navy which operates dozens of reactors in wartime vessels travelling millions of miles and enduring rough conditions and even combat with one of the best safety records of any industry.
The US has 2 sunk Nuclear submarines (129 and 99 lives lost). With at least USS Thresher being related to a loss of propulsion and thus at least indirectly the reactor. Considering how few where in service and none being sunk in wartime that’s not a great safety record. https://en.m.wikipedia.org/wiki/List_of_sunken_nuclear_subma...
The cause of USS Scorpion’s sinking is unknown so it may be related to the reactor or it may not.
We're discussing safety record for nuclear power specifically, not lost ships for any reason. The USN has about half of all the reactors running by the USA. How is that a "few"?
If you read the page about USS Thresher then it clearly explains it had nothing to do with the reactor and was a "high-pressure water spraying from a broken pipe joint may have shorted out one of the many electrical panels, causing a shutdown ("scram") of the reactor, which in turn caused loss of propulsion" followed by other personnel and procedure issues that led to a sinking.
That quote directly says the loss of reactor power was part of the chain of events leading to a sinking.
Sure it did not blow up, but that does not mean the reactor was safe to use as a critical piece of equipment. Loss of power is a huge deal and the reactor being unable to recover in that situation is a major design flaw.
That's like saying a torpedo hit the sub and the reactor stopped working so it's a reactor problem. You're being disingenuous. The reactor was not the part that malfunctioned.
Again, if you read that page then you'll find several other causes like faulty ballast tanks that didn't eject, isolating the steam system too quickly and eliminating potential energy from the turbines, and inexperienced personnel not restarting the reactor after shutdown. If just the ballast tanks had worked then the sub would be safe for rescue, if the steam was used then it could continue to drive to surface.
According to an official report [1]: "U.S. Nuclear Powered Warships have safely operated for more than 50 years without experiencing any reactor accident or any release of radioactivity that hurt human health or had an adverse effect on marine life. Naval reactors have an outstanding record of over 134 million miles safely steamed on nuclear power, and they have amassed over 5700 reactor-years of safe operation." and this is from several years ago.
Steam turbines are part of a nuclear reactor. If it had used batteries and Diesel engines there would have been no steam system to fuck up.
I absolutely agree it was not the single cause of failure, it was even recoverable in theory. But, if the reactor had continued to supply power, like large result battery systems tend to, then it would have likely made it. That directly means using a reactor was less safe to put on the sub.
If an aircraft lost all engine power over the ocean because of a defective engine design and thus crashed. Well you can bet the navy would blame the engines, but with nuclear power they care about perception. The loss of a crew is acceptable risk, the loss of nuclear reactors from a public backlash is a loss of capability.
PS: They can and do mitigate this risk by having large battery systems for redundancy, it’s only a few hours of power. But, it can run a redundant electric engine to move the sub, and that’s an important lesson learned.
If it was a diesel-electric then the broken water-pipe would've shorted out the batteries and electrics, and the flooded engine room would've stopped the engines, resulting in the exact same loss of power.
The fact is that the reactor didn't fail, it worked normally. The steam system didn't "fuck up" but was used incorrectly. The part that did fail was the ballast tank safety system. Diesel-electrics aren't a magical answer and have major disadvantages (like the need for air intake in a submarine).
It seems you're arguing that nuclear-powered designs aren't good, which is an entirely different topic than the safety record of the reactors themselves. Bad design of a system is not an argument that that core principles are inherently wrong, which is exactly the same thing any nuclear expert will tell you about Chernobyl.
It’s very possible that a broken pipe would have shorted out all batteries on an equivalent non nuclear sub. But, that would also have been a significant design flaw.
Anyway, I think this is more a case of disagreements about what constitutes a system than about what happened. I would say if the design of a critical system lets people mess up then that’s a failure of the design and the system. Chernobyl was very much a case of operators doing a long series of dumb things as people do. Similarly, the operators caused an issue with the steam system, but that just means the system and it’s design was also faulty. (IMO, the steam system should be considered part of the nuclear power plant as civilian nuclear power plants also use a steam loop for similar reasons.)
I would rate the US Navy highly on nuclear safety operations especially over the last 50 years.
