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Small nuclear reactors: tiny NuScale reactor gets safety approval

popularmechanics.com

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Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#291

Post by Pfhreak »

birdyrooster wrote: post #231
jhallenworld wrote: post #52

Here is the NRC website about this reactor: https://www.nrc.gov/reactors/new-reactors/smr/nuscale.html Here is an interesting sub-report: https://www.nrc.gov/docs/ML2022/ML20224A525.pdf Information withheld for security reasons. One item concerns the "ultimate heat sink". What happens when the ultimate heat sink is lost? Well a design assumption is that it is not lost: https://www.nrc.gov/docs/ML2020/ML20205L410.pdf…

>What happens when the ultimate heat sink is lost? The reactor ceases to transmit power and is shutdown for maintenance?

Reactor's aren't boolean. If a reactor has no heat sink and attempts to shut down, there's still going to be a catastrophic amount of heat to disperse.

That said, rapidly losing the UHS should be incredibly rare/difficult (as several other posters have mentioned).

Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#292

Post by pvaldes »

manigandham wrote: post #114
marshray wrote: post #67

Earlier quoted context omitted.

If only a method for permanent disposal of nuclear waste actually existed.

We could dump it into the ocean and not worry about it. There's so much cooling capacity and radiation shielding in the oceans alone that we'd never run out of space, so all of the current disposal strategies are way above and beyond what's needed. Containment is solved problem. It's important to note that other energy types also produce waste. For example, coal ash is incredibly toxic and hard to dispose of, and we…

> We could dump it in the ocean and not worry about it

This is the things that make me cringe when I see this people saying again "This time will be different, we promise".

Look mum, radioactive tornadoes coming from the ocean...

Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#293

Post by runarberg »

karaterobot wrote: post #286
runarberg wrote: post #257

Earlier quoted context omitted.

We have many proven solutions to the climate disaster, including, carbon tax, renewable energy, cleaner and more efficient infrastructure, telecommuting, international agreements, etc. Going after a single unproven solution (yes this includes non-existing types of nuclear energy too) is just magic at this point and it doesn’t work.

I wouldn't say those approaches have turned out to be sufficient by themselves, so far. Why not keep improving them, and try additional measures with some hope of success and little risk?

All of these solutions have been deployed on small scales and are proven to work. However they always stop short of implementing on the scale required for the problem. International agreements in particular worked really well to stop the destruction of the ozone layer. However they have never agreed on enough carbon emission reduction for any significant reduction in climate harm.

Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#294

Post by Pfhreak »

jacobwilliamroy wrote: post #274
dodobirdlord wrote: post #88

Earlier quoted context omitted.

The world is filled with naturally occurring phenomena far more dangerous than a big pile of low-grade nuclear waste. The really dangerous stuff ceases to exist after a few decades of sitting in a cooling pond, and then what’s left has such a long half life that it’s not particularly threatening. Water is an incredible radiation dampener, and the ocean is already chock full of dissolved uranium. The only reason we do…

So we can just put it all in your house and you'll be cool with that? After all, there are more dangerous things out there, and we won't be putting any of those in your house, so that makes it okay right?

This question is asked in incredibly bad faith. No one anywhere has suggested storing waste (nuclear, coal ash, solar manufacturing, or any other kind of waste) in anyone's home. Or even their neighborhood.

Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#295

Post by birdyrooster »

Pfhreak wrote: post #291
birdyrooster wrote: post #231

Earlier quoted context omitted.

>What happens when the ultimate heat sink is lost? The reactor ceases to transmit power and is shutdown for maintenance?

Reactor's aren't boolean. If a reactor has no heat sink and attempts to shut down, there's still going to be a catastrophic amount of heat to disperse. That said, rapidly losing the UHS should be incredibly rare/difficult (as several other posters have mentioned).

If it's big enough and makes enough noise, it will be harder to lose.

Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#296

Post by liability »

baybal2 wrote: post #204
liability wrote: post #91

Earlier quoted context omitted.

> Nuclear reactors take ages to ramp up and down. Naval reactors are apparently very fast in this regard, so it's evidently not an inherent property of nuclear power. (The USN also has an unparalleled record of safely operating reactors; more that 5,000 reactor-years clocked without major incident.)

> Naval reactors are apparently very fast in this regard, so it's evidently not an inherent property of nuclear power. Ramping up is easy, ramping down... not so much. It's not as much of an issue if you swim in your coolant, hence naval reactors are unique in being able to ramp both up, and down quickly.

Most civil reactors are next to lakes or rivers so it seems like they should have plenty of water. Is it a matter of civil reactors using smaller[cheaper] plumbing and pumps? My intuition is that Naval reactors are built to be very responsive because that's useful for naval applications, but civil reactors aren't built like that because that ability has less relative value for civil reactors.

Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#297

Post by cameldrv »

_jal wrote: post #265
AngryData wrote: post #258

Earlier quoted context omitted.

It also helps to not be running a reactor based on designs from the 1950s and then decades later ignore all the known potential problems.

It does, but it makes sense to explore fail-safe designs. Depending on a lack of incompetence in dangerous systems works until it doesn't. To the extent that these things can simply halt when incompetently managed, they should. If anyone disagrees, I'd like to know why they think the next hundred years are going to be so much freer of political shortsightedness and corruption than the last hundred.

Fukishima is a perfect example. Unit 1 had been retrofitted with an isolation condenser, which should have been able to prevent a meltdown even with no power, but it wasn't activated, for reasons that remain murky.

Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#298

Post by jhayward »

kortex wrote: post #256
baybal2 wrote: post #195

Earlier quoted context omitted.

> This is huge. Not only are micro reactors far more economical No, they aren't. They are more expensive per unit of power produced, by far bigger than any other powerplant in practical use. The only way I see nuclear getting economical is it getting bigger . Nuclear's biggest advantage after the cost of fuel is its huuuuuuge power density, and power scalability. With currently technology level, it's possible to gene…

Bigger means bespoke. More NRE, more paperwork, more one-offs. Smaller means the entire supply chain is simpler and easier. Management is easier. And of course, the more times you do something, the easier and cheaper it gets. Mass production is a no-brainer.

> Mass production is a no-brainer.

This is very much an unproven assumption. There is nothing in the history of nuclear technology to suggest that what most industries experience, an industrial learning curve that lowers production cost, will be found for these reactors. In fact, just the opposite - the more experience we get with them the more likely we are to find problems that are very expensive to fix. This is even more true now that they've given up on doing serial production in a single factory.

Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#299

Post by ClumsyPilot »

dheera wrote: post #271
ses1984 wrote: post #157

Earlier quoted context omitted.

There's no research being done on materials to safely contain molten radioactive salt, that research could be dangerous, pretty much only superpowers would have the resources to do the research.

> materials to safely contain molten radioactive salt Wouldn't a giant steel or stone vat work, in theory?

The problem is that the nuclear reactions produce many random materials which in turn might be corrowive to the reactor veasel. Dont forget that the vessel has to last decades, so even minor corrosion is a big deal.

Re: Small nuclear reactors: tiny NuScale reactor gets safety approval

#300

Post by ClumsyPilot »

ses1984 wrote: post #193
godelski wrote: post #152

Earlier quoted context omitted.

Nuclear power plants were designed with this in mind. It would take a substantially larger earthquake to damage a nuclear power plant and cause it to leak than a commercial pool. Such a comparison is in bad faith and disingenuous.

It's a people problem. People are fallible on the best days, assuming everyone did their very best from nuclear physicists to construction workers, mistakes are made. You take steps to reduce the risk. Research gets review. Engineering schematics get review. Construction gets inspection. Still some mistakes will get through. And people always act their very best all the time right? You can even have a perfect design,…

A sufficiently large pool can be built, that any plausible leak will take many days. Think about it: a million liters of water take a long time to dissapear, after all lakes stay there for a long time without rainfall. Weve built many many ponds, it's not hard.
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