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Small nuclear reactors: tiny NuScale reactor gets safety approval

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

#111

Post by stickfigure »

adrianmonk wrote: post #39
EricE wrote: post #12

This is huge. Not only are micro reactors far more economical, it dramatically reduces the need to maintain a massive nationwide grid and provides flexibility to people in remote areas including greater autonomy. Efficiency should be greater without massive transmission line losses. Might start fewer fires in California too.

I'm not an expert, but I'm not convinced about it reducing the need to maintain a nationwide grid. Nuclear reactors take ages to ramp up and down. It's basically going to be generating the same amount of power 24x7, but demand is going to fluctuate. The more other areas you're connected to, the more opportunity there is to send that power to someone who can use it. Obviously there's a law of diminishing returns at so…

Nukes are slow from a cold start but they can throttle up and down with load.

https://en.wikipedia.org/wiki/Load_following_power_plant#Nuc...

Modern nuclear plants with light water reactors are designed to have maneuvering capabilities in the 30-100% range with 5%/minute slope.

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

#112

Post by karaterobot »

xigency wrote: post #68
vlovich123 wrote: post #65

Earlier quoted context omitted.

Is there a paper on that? 40 trillion sounds like a lot and I’m curious how that number is generated.

If you could solve climate change for less than that, I think it would be splendid. To put that number in context, which is just an order of magnitude, it's $5,000 for every person on Earth, about 1.5x the current US national debt, and just under the combined market cap of NYSE+NASDAQ. As an existential problem for humanity that doesn't currently have a solution, I think that's a decent cost estimate.

This is in no way to disagree with your overall point, but marine cloud brightening looks like it might be a fairly cost-effective solution to climate change. It's unproven, but not an insane gamble either, and it has little risk of second-order consequences if it doesn't work. All that at a cost of single-digit billions per year.

https://en.wikipedia.org/wiki/Marine_cloud_brightening#Costs

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

#113

Post by throwaways885 »

Retric wrote: post #89
xigency wrote: post #68

Earlier quoted context omitted.

If you could solve climate change for less than that, I think it would be splendid. To put that number in context, which is just an order of magnitude, it's $5,000 for every person on Earth, about 1.5x the current US national debt, and just under the combined market cap of NYSE+NASDAQ. As an existential problem for humanity that doesn't currently have a solution, I think that's a decent cost estimate.

Climate change his hardly an existential threat for humanity. We survived the last ice age with stone tools, this is a less severe change. Economic impacts from things like rising sea levels really depend on how much we spend on maintaining things as they currently are vs adapting to the new normal. Aka do you live below sea level, raise the city, or move somewhere else. https://en.wikipedia.org/wiki/Raising_of_Chica…

People fleeing the climate alone could collapse the global food chain. I personally thing we're a little too interconnected in the name of efficiency.

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

#114

Post by manigandham »

marshray wrote: post #67
RhodesianHunter wrote: post #58

Earlier quoted context omitted.

This is IMO a positive for nuclear, not a negative. You're forced to confront the cleanup as opposed to fossil fuels, where you just blow your waste out into the atmosphere and make it the commons' problem.

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 create much more of it every year.

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

#115

Post by newacct583 »

ColanR wrote: post #103
natcombs wrote: post #100

Earlier quoted context omitted.

>> What happens when the ultimate heat sink is lost? What's an example event where the ultimate heat sink might be lost?

No expert, but if it's a pool of water then an earthquake might cause a leak?

Or an attack, of course. Or some other event (social unreset, invasion, coup, etc...) causes an evacuation of staff and it boils off during the resulting excursion.

People tend to have poor mental models for the long tail of external failures that happen in real life. It's easy to imagine that things that have never happened in the last century would Never Happen. But... they will, somewhere.

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

#116

Post by jabl »

jessaustin wrote: post #94
jabl wrote: post #73

Earlier quoted context omitted.

The idea is to put multiple reactors at the same site, not to spread out mini reactors all over the landscape. So the end result would be a powerplant that produces about as much power as a "normal" nuclear power plant, just that it contains many small reactors instead of a few big ones.

This undermines some of the claimed benefits. A bunch of little Fukushima Daiichi reactors in the same location wouldn't have fared any better than the actual Fukushima Daiichi reactor.

In this particular case, a power plant with these nuscale reactors would probably have survived a Fukushima type accident. One effect of being small is that the reactors are designed to be passively cooled after shutdown, using convection instead of pumped flow. So there is no need for emergency diesel generators to keep the coolant pumps running.

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

#117

Post by brandmeyer »

natcombs wrote: post #100
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? What's an example event where the ultimate heat sink might be lost?

Many inland rectors are built on waterways. A plant can shut down due to drought. That's a slow enough process that you have plenty of advance warning, though.

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

#118

Post by gambiting »

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…

Another option which is completely safe and permanent* is drilling a borehole few km down and dumping the waste there. It's not coming back no matter what. The research done into it shows that "only" 800 boreholes would be required to store literally all nuclear waste ever produced.

https://en.wikipedia.org/wiki/Deep_borehole_disposal

*to a point where it was actually brought up as a negative, because if we ever wanted to recycle that waste into something else, it's literally impossible this way.

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

#119

Post by erentz »

marshray wrote: post #106
erentz wrote: post #77

Earlier quoted context omitted.

Yes. It appears to very explicitly is about DOE sites, national labs with waste dating back to the Manhattan project and Cold War. This figure would seem to be better described as the clean up cost for our nuclear weapons programs with maybe a small side dish of reactor research in places like INL.

The defense waste is just a fraction of the total: "The U.S. commercial power industry alone has generated more waste (nuclear fuel that is "spent" and is no longer efficient at generating power) than any other country—nearly 80,000 metric tons. This spent nuclear fuel, which can pose serious risks to humans and the environment, is enough to fill a football field about 20 meters deep. The U.S. government’s nuclear we…

Ok now you’re conflating two separate things. The link and original figure you shared was about DOE sites. From your link: “EM’s mission is to complete the cleanup of nuclear waste at 16 DOE sites...” You suggested this was connected with commercial reactor waste, it wasn’t about that.

Commercial reactor waste is not anywhere near the same kind of beast. It’s contained and easily disposed of when the US eventually embraces science again. Other countries don’t have as much problem and are building deep geologic repositories. Canada even let local communities bid to take the waste.

If your in the PNW take a visit to Hanford when you can. What they did on these DOE sites during the nuclear weapons programs is absurd to think about with what we know today. They just buried all kinds of random toxic stuff everywhere and didn’t even keep records.

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

#120

Post by normanmatrix »

I was thinking Nuclear would be the stable baseline for renewable. But this is not a sustainable option. We need to enforce hydrogen.

Do not submit to the fallacy of nuclear waste disposal. First Elon needs to fix space travel and make transport into the sun feasible. And we will have iter by then.

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