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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

#301

Post by tootie »

ses1984 wrote: post #157
kbenson wrote: post #138

Earlier quoted context omitted.

Wasn't the big push (or maybe big PR push) for more research and development of Thorium reactors a few years ago because they fail closed/safely? That seems like the kind of thing you'd want for smaller reactors (which I assume means more and more geographically diverse, but don't really know).

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.

Bill Gates is funding a company called Terrapower that is planning to bring compact MSR to market in the next 10 years. They already have working prototypes but are still a few years behind NuScale.

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

#302

Post by pvaldes »

RangerScience wrote: post #131

Thinking about the cooling pool: Could you just make an off-shore in-ocean "farm" of these?

> Could you just make an off-shore in-ocean "farm"

Not! Ocean is inherently unstable!.

The first serious storm would dislodge and damage the whole farm crashing one module against the other before to vomit them in the shore. Some modules just would dissapear.

And then you have a humongous environmental damage and a really expensive rescue problem trying to clean the fragmented mess.

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

#303

Post by ClumsyPilot »

jaggirs wrote: post #189
moneytide1 wrote: post #174

Earlier quoted context omitted.

There's one in Finland: https://en.m.wikipedia.org/wiki/Onkalo_spent_nuclear_fuel_re... They have thought thousands of years ahead and set up many different types of warning signs and symbols in case a future civilization discovers it.

No, they put zero warnings. Warnings only make it more likely that someone decides to start digging.

The idea that civilisation collapses and then recovers to the specific extent, where it is advanced enough to have coal-mines or similar, but not to know about radiation. Then it must find this particular repository and start digging, and die. Thousands of years must pass but they must dig up this sight withing a particular 100-year period of their development.

This is such a stupidly contrives scenario that you might as well plan for an alien incasion or zombie apocalypse. Lime prerequisite for that theory is civilisation collapsing, our investment in making sirebcovilisation does not xollapse is zero. You deal with it by making sure civilisation does not collapse.

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

#304

Post by pvaldes »

X6S1x6Okd1st wrote: post #217
marshray wrote: post #67

Earlier quoted context omitted.

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

If only a method for permanent disposal of excess CO2 was viable.

Do you mean, like coral reefs?

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

#305

Post by credit_guy »

cm2187 wrote: post #236

I don’t understand what makes small reactors desirable. Don’t you loose economies of scales, not only production, but also demand (ie if you have small local sources of electricity you miss the diversification of the demand you have in the central grid and you need to overprovision a lot more)?

> Don’t you loose economies of scales

On the contrary, you gain economies of scale. The way the economies of scale work is if you build n identical widgets, it costs you less than n times the cost of building one single widgets. In other words the unit cost of a widget goes down as the number of produced widgets increases.

If you want to produce a bigger widget though, you generally have diseconomies of scale. For example the Saturn V rocket was about 20 times bigger than the Titan 2 rocket (from which it was derived) but cost about 60 times more.

So, if a Gigawatt-size nuclear power plant is too expensive to build, you build 20 plants of 50 MW each. This is how you achieve economies of scale.

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

#306

Post by bluejellybean »

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?

Absolutely, why not? As long as the waste dealer is offering a deal that is satisfactory for me as the landowner/waste site, I would happily store said waste. Your question is a bit absurd; nobody is suggesting to keep it inside of someone's home. Should an individual not be allowed to make rational decisions about their land and property? If I owned 20 square miles in the desert, why shouldn't I be allowed to lease my land to waste storage companies? The waste storage people are already regulated to death, for a good reason, and as long as the waste on site is stored safely why should I or anyone else mind?

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

#307

Post by throwaway0a5e »

throwaway0a5e wrote: post #164
thekyle wrote: post #158

Earlier quoted context omitted.

Wow. How do they design them to withstand a strike from a 747? That seems really difficult.

They shot an F4 target drone at a block of "reactor grade" concrete wall back in the 80s and they took measurements and did science on the resulting lack of damage and concluded that a reactor can shrug off one of anything. They didn't change containment buildings to be plane proof. It's just a side effect of the design required to contain a melting down reactor with a sufficient safety factor.

video of the test https://www.youtube.com/watch?v=F4CX-9lkRMQ

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

#308

Post by godelski »

pvaldes wrote: post #277
godelski wrote: post #150

Earlier quoted context omitted.

Nuclear sites are designed to withstand a strike from a commercial airliner (747). Like you, the designers imagined many of the events you mentioned and more. A good rule of thumb is that if you, a non-expert, can think of a scenario within 10 minutes, an expert has probably already thought of this scenario. Nuclear power plants and weapons sites have always been considered targets and thus considered extra scrutiny…

> the designers imagined many of the events you mentioned and more Designers are awesome. Sadly they were also unable to find some time in 50 years to raise a wall a few m so it can stand a Tsunami. It seems that the extra scrutiny, was not so extra in the real life when the company will need to allocate real money.

The event you are referring to was also a freak event. The Tohoku earthquake was the 4th largest _ever_ recorded and the largest ever recorded in Japan (by 0.2M, it is a log scale btw). The closest earthquake to that, in the region, in the previous 100 years was 0.7M lower (and the 6th largest ever recorded, in the area). The Tohoku earthquake also resulted in one of the largest tsunamis ever recorded.

We should note that a lot of rare things happened all at once, more than just the freak earthquake and freak tsunami. There is no such thing as perfect. But consider that there were no lives lost due to the reactor accident. Yes, there is economic damage, but that is the worst. Lives were not lost and the environment was not irreparably damaged. Nature has actually started to take back the region and it more looks like a scene out of I Am Legend rather than The Road or The Book of Eli. I do not intend to dismiss the event, as it is concerning (and we've learned a lot since then), but however you measure it coal or oil or gas have had far greater environmental (or human/health) impacts than nuclear. The difference is that it is more in our mind. Despite the Fukushima cleanup estimate (2x Chernobyl's) costing about 9x Deep Water Horizon (2010) I'll let you decide what costs more[0], even if we ignore all the costs to health and atmosphere. There simply is no free lunch.

[0] https://ourworldindata.org/oil-spills

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

#309

Post by et2o »

jjoonathan wrote: post #169
adammunich wrote: post #85

Earlier quoted context omitted.

It's really hard to comprehend just how much heat a reactor can make from decay alone. Like... boiling a hot tub in only a minute.

Have people really found no way to dump it in an emergency with t^4 transfer?

What is t here?

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

#310

Post by et2o »

godelski wrote: post #152
sandworm101 wrote: post #134

Earlier quoted context omitted.

You don't need to be an expert. Ask anyone who has owned an in-ground pool. Leaks are rare but do happen.

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 not bad faith or disingenuous. Fukushima happened because of an earthquake, remember?
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