Molten Salt and Pebble Beds and Breeders, Oh My! Alternative Reactor Designs (Part II)

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Our discussion of alternative nuclear reactors concludes with a look at the Integral Fast Reactor, Molten Salt Reactor, Pebble Ped Reactor, and other Generation IV designs.

[@limabravo6065]

Aside from the misconceptions surrounding waste, most people have no idea that there are as many different types of nuclear reactors as there are. A lot of the safer types of reactors that either can't melt down or only do so if the wildest of scenarios come up were looked at and abandoned by the US government because they couldn't produce weapons grade fuel. Thorium reactors are a great example, because while they do produce fissile uranium suitable for a bomb that fuel is contaminated with an even less stable uranium isotope that if not removed could cause any weapon it was in to just do its own thing instead of being detonated when we wanted. Back when serious nuclear reactor research was being done the government was footing the bill and really only concerned with fuel for weapons which is extremely difficult to produce. The US having thousands of weapons at the end of the cold war required massive effort in order to produce the required tons of uranium 235 and plutonium 239. Chernobyl, and later Fukushima werent the result of inherently dangerous tech, rather irresponsible and stupid humans making catastrophic mistakes. Chernobyl was built on the cheap with a fatal flaw, and Fukushima was built on the beech on a coastline prone to earthquakes, tsunamis etc... etc.... in other words the exact place you don't want a regular power plant let alone a Nuke plant.

[@Grumskiz]

The German PBRs showed some serious problems with the concept in general that offsets benefits: - the graphite moderated reactor will be uncontrollable if water enters it - there is no online monitoring within the pebble bed, you only have the coolant temp - pebbles don't flow freely, despite being low friction and surrounded with helium - since pebbles don't flow freely, control rods (as in the THTR-300) will crush them on insertion PWRs may be boring technology, but their control and management is well understood.

[@kasel1979krettnach]

pebble bed is such a typical german overengineered idea, that some professor was able to push through. it has so many dis-advantages that it is almost silly. (the control rods are guided in pipes of course, you can remove that)

[@DumbSkippy]

#OurOwnDevices, Thank you so much for making this video. I'm just an amateur but followed every word with glee. Kudos and much gratitude from Western Australia!!

[@benjammin9745]

This channel is soooo gooood

[@stickynorth]

Let a hundred flowers bloom or in this case, nuclear reactor designs flourish... Just as long as we recycle the high-level waste and store the low and medium waste in deep level waste repositories...

[@kasel1979krettnach]

we have deserts. we can store it open air, nearly forever... the amounts are really not significant compared to other waste streams

[@nos9784]

​@@kasel1979krettnachdunno about deserts... wouldn't deep sea sediments be the geologically most stable place, least likely to be disturbed by low- tech civilizations?

[@j.s3612]

interesting

[@RiDankulous]

This is promising. This method theoretically has less likelihood of failure. Of course, the pebbles and containers need to be manufactured according to specification to be safe, just like any other nuclear reactor type. If there's flaws in the manufacturing, the results can be just as bad.

[@thomaswade3072]

They've made basically no traction so far

[@Reagae-fv3cp]

I love me some super critical steam as much as the next guy but pwr is an extremely safe, reliable and proven technology (when implemented corrrectly). I know supacrit plants are safe, but the inherent risk of operating at more than 3x the pressure is just… uncomfortable to my untrained brain.

[@GothGuy885]

but when it rains, does it pour -out mega watts? oh molten salt, I read that wrong and thought it said Morton Salt 😁

[@PaulHigginbothamSr]

So then every time pebble bed reactors became critical, they plugged up on the outlet of the pebbles. Also the triso fuel pebbles were less robust than thought releasing it's actinides into the gas cooling material thus contaminating everything in the outlet. I personally see no reason to test triso fuel pebbles as reactor methods because of 1. The amount of fuel needed to go critical. 2. Delivery methods of pebbles. 3. Breakdown of fuel unknown in length of time of failure with concomitant radiation release & or reactor and surrounding area contamination. 4. All these demerits reduce and or eliminate pebble bed as a power source. Too risky.

[@markdavis8888]

Sodium will always find water and burn down the reactor on TV. Salt will never cause these problems.

[@ravener96]

Except salt finding water will also be destructive, as it vastly increases the corrosiveness of the salt. Leaking the reactor contents into the outer vessel is also considered a bad look.

[@Inflorescensse]

Its too bad molten sodium is opaque, if they could just have seen through it to id problems so many shutdowns and delays could have been avoided.

[@AsbestosMuffins]

idk if any utility could stomach the risk of a liquid metal. only Russia really puts up with the dangers

[@nibiruresearch]

Thank you for this clear explanation of the past and present situation. The main reason for not developing the Thorium Molten Salt reactor is most likely the influence from the oil and coal companies, both producing the most pollution in the world. They see this development as a threat to their business. And the many people who work in those industries and the shareholders will do everything in their power to stop or at least slow down this development.