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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

#351

Post by Klinky »

rstupek wrote: post #200
Klinky wrote: post #166

Earlier quoted context omitted.

You're underplaying the danger and overplaying the value. Who exactly is investing in this "green gold"? If it's so valuable why does no one actually want it, and why is the DoE stuck with half a trillion liability?

Isn't the "green gold" as you state it what the traveling wave reactor folks https://www.terrapower.com/our-work/traveling-wave-reactor-t... hoping to use to generate their power?

A nuclear concept product. It's probably eternally "10 years from commercialization".

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

#352

Post by Lineup »

phkahler wrote: post #144
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.

And so a pool of water is not enough because it will boil away. A continuous flow must be present that can not be interrupted.

Making statements as fact does not help to clarify the discussion. Try posing a question instead. You are not adequately informed on reactor design or operation

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

#353

Post by valuearb »

manfredo wrote: post #109
Retric wrote: post #89

Earlier quoted context omitted.

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…

The last ice age occurred gradually over the span of millennia. Anthropic climate change is occurring in an instant by comparison. Not to mention, humanity survived by mass migration, something that's a lot harder for integrated global economies to do. Few believe humanity is going to go extinct. But extinction of industrialized civilization is a more real concern. And the collapse of industrialized civilization will…

Humans aren’t at risk from climate change, it’s all the other species without our powers of quick adaption.

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

#354

Post by selectodude »

runarberg wrote: post #285
throwaway0a5e wrote: post #279

Earlier quoted context omitted.

You ever notice that the countries where the people are pissed off at the rich for taking too much, pissed of at the government and pissed off about climate change are all countries where basically everyone is fed, clothed and has running water and stable electric power? Advancements in technology (including GMO crops) and productivity in general have massively raised standards of living in the developing world. Rais…

I’m not sure anything you say here is true: * I really doubt GMO has raised the standard of living for the average person. * I really doubt people in less then stable economy have any less salt towards the rich, the government, or polluters. * I really doubt there is a correlation between the standard of living caring about your neighbors. So to answer your question. No. I have never noticed that countries where peop…

>I really doubt GMO has raised the standard of living for the average person.

Then you are absolutely not paying attention at all whatsoever. In fact, the majority of the impact of GMO crops has been felt in countries where there was literally not enough food to go around. You’re welcome to your organics in a country as food secure as in the west but starving poor and middle income countries is not okay.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4218791/

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

#355

Post by selectodude »

Dylan16807 wrote: post #332
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.

All of those reduce emissions but they don't stop them and they don't do anything about the existing already-too-high levels.

We have methods of removing carbon out of the atmosphere. They all have the same thing in common, they require a whole lot of electricity. We have something in our back pockets that can generate a whole lot of electricity without any additional carbon...

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

#356

Post by i_am_proteus »

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…

Nuclear engineer here. I've read through a good portion of the regulatory submission to the NRC and have a few takeaways that oppose some of the less-well-informed takes in this thread:

- The reactor differs substantially from existing PWRs by encasing the primary in double containment, using natural circulation flow for both normal operation and emergency cooling. There are no pumps needed (or installed) to move coolant through the reactor.

- During normal operation, the primary is entirely contained within the primary containment, and circulates naturally, using the differential temperature and gravity. The steam system can is used to remove heat.

- During an emergency, valves open to admit the reactor coolant into the backup containment. These valves are normally held shut by hydraulics with positive control from electronics-- their failure mode is to open with no other operator action in case of a loss of power. No additional operator action is needed to initiate the emergency cooling flow, which is also a natural circulation loop to the backup containment shell, which then conducts heat to the pool.

- The backup containment shell is designed to withstand hydrogen explosions such as those that occurred at Fukushima, and which was possibly prevented at Three Mile Island by venting (whether there was a hydrogen explosion at TMI-2 is not fully understood).

- There is no mechanism for positive reactivity addition via graphite moderator rod such as in the Chernobyl design. The specific failure mode at Chernobyl is not possible with this reactor.

- The pool is specified as a stainless-steel-lined reinforced concrete and designed to withstand earthquakes. The safety systems are such that no reactor electricity supply is needed to remove heat-- the pool could be filled e.g. from a fire truck, and the immediate decay heat from shutdown does not require any additional heat removal or water addition. So the failure mode we saw at Fukushima (inability to remove decay heat due to loss of electricity) and hydrogen explosion breaching containment does not apply to this design.

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

#357

Post by willis936 »

anonymousiam wrote: post #347

From the article: "In the event of any runaway reactor event, NuScale says, the reactor quenches itself in its pool, making it 'passively safe.'” So what happens when an earthquake causes a rupture of the pool barrier and all the water leaks out?

This is a solved problem. Tokyo is a good example.

https://en.wikipedia.org/wiki/Earthquake-resistant_structure...

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

#358

Post by core-questions »

regularfry wrote: post #123
core-questions wrote: post #81

Earlier quoted context omitted.

Flaws? The meltdown was caused by a deliberate action on behalf of people with control of the plant. I haven't watched Chernobyl because I prefer to not get my history from television shows with a narrative axe to grind.

My understanding is that those actions were only capable of causing the problems they did because of specific design choices involved in the coolant and moderation systems. Is that wrong?

That's not wrong so much as it is a disingenous way of looking at the problem. It's like saying the Titanic only sank because there was no system that prevented them from sailing it into an iceberg; I mean, alright, sort-of true, but sort of a "missing the forest for the trees" sort of take, isn't it?

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

#359

Post by rtx »

godelski wrote: post #331
natmaka wrote: post #320

Earlier quoted context omitted.

In France this 'success story' led to a state law (2015-992, from 2015, the "loi relative à la transition énergétique pour la croissance verte") stating that the part of nuke-produced electricity must fall to less than 50% in 2025, from 72% then, and that renewables must replace it. In France nuke-power is backed by gas (which produced 10,3% of gridpower in 2017). The sole reactor currently planned (Flamanville-3) is…

I'm unsure what you are suggesting here, so I want to be extra clear about the French policy and current state of affairs. As in stands, France has one of the lowest CO2 emissions per capita[0][1]. No one is saying that we should _only_ use nuclear. Not diversifying your energy portfolio is a terrible idea. France is trying to reduce its dependence upon nuclear (which is a good idea) and replace its fossil fuel infra…

Grid should only be nuclear. Renewables and batteries will be major source of pollution going ahead. I am not sure why green groups are pushing those.

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

#360

Post by rtx »

ClumsyPilot wrote: post #303
jaggirs wrote: post #189

Earlier quoted context omitted.

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 migh…

Then they will know about radiation.
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