Ultra Safe Nuclear • Hacker News Board

Re: Ultra Safe Nuclear

#181

Post by wazoox » Thu, Sep 17, 2020, 9:13 PM UTC

rektide wrote: post #45

3pt14159 wrote: post #7

Earlier quoted context omitted.

Deaths per joule are the lowest out of any major fuel source except for maybe wind, which is debatable depending on your assumptions about the future.

Except... we don't know what the deaths are. It will take tens of thousands, hundreds of thousands of years to know what the death toll is from nuclear power. Because humanity is stuck with the waste for hundreds of thousands of years. We use only tiny amount of the energy available, then have waste to deal with through the ages. I'm in favor of nuclear, but wow are we ever terrible at innovating & trying to make a r…

We're stuck with the gaseous waste from fossil fuels for millennia. We're stuck with megatons of radioactive coal ashes forever. We're stuck with toxic chemical compounds necessary to build anything industrial at scale (including solar panels, batteries, windmills etc) forever too.

Re: Ultra Safe Nuclear

#182

Post by manfredo » Thu, Sep 17, 2020, 9:14 PM UTC

atlasunshrugged wrote: post #164

manfredo wrote: post #97

Earlier quoted context omitted.

> 1. yucca mountain can not sustain a million years due to strong seismic activity Where does it say this? Here's the paragraph under earthquakes: > DOE has stated that seismic and tectonic effects on the natural systems at Yucca Mountain will not significantly affect repository performance. Yucca Mountain lies in a region of ongoing tectonic deformation, but the deformation rates are too slow to significantly affect…

As a Nevadan who is semi-involved in local politics, I can also tell you that Yucca is so contentious and such a career killer for politicians that I have no doubt that any Nevada state or local agencies would be under tremendous pressure to find any and all reasons to make Yucca an unacceptable place to store the used material.

Is it really? Yucca mountain is basically right next to the site where the military conducted over a hundred nuclear weapons above ground, and a few hundred more below ground. Putting nuclear waste in an area that's already contaminated essential presents no change.

Re: Ultra Safe Nuclear

#183

Post by agumonkey » Thu, Sep 17, 2020, 9:14 PM UTC

evgen wrote: post #149

Manfredo_1 wrote: post #124

Earlier quoted context omitted.

By "cultural changes" you mean energy shortages. Realistically, this would most likely result in leaders getting elected out of office and resuming the use of fossil fuels. Regular blackouts are immensely unpopular.

Those of us who lived through the oil shock in the 70s are having a laugh at the 'just cut the energy supply' path. Would love to hear from people who endured the UK at the height of their 3-day week to see how keen people were about this forced change...

I think the context matters a lot:

- this was a brutal unplanned event

- people were still trying to reach higher comfort, psychologically unsettling

Re: Ultra Safe Nuclear

#184

Post by epistasis » Thu, Sep 17, 2020, 9:14 PM UTC

cmehdy wrote: post #168

epistasis wrote: post #159

Earlier quoted context omitted.

You can't "help" me understand your claim because it is baldly false! There's an entire field that models different grids and transitioning to carbon free energy. Using fine-grained weather patterns, they optimize for various factors such as cost, by timing out deployments of renewable resources, nuclear, transmission, storage, etc. using projected costs over the next few decades. There are huge fights in the field,…

I'm not even sure what fight you're trying to pick here, because I'm all for renewables and energy. It's painfully obvious that no, renewables alone do not have the ability to cover at a low-CO2 footprint and continuous usage the energy needs that we currently have and that are, even with reduction of consumption in richer countries, bound to grow on the whole as population follows the models that indicate about 9 bi…

My "fight" is that you have now made two plainly false claims: 1) physics precudes renewables from providing our energy needs. This is just a silly claim. There are no such "physics" and if you think that "energy density" stops this from happening, you clearly haven't run any numbers.

2) Renewables aren't reducing carbon output. This is also incredibly bizarre.

> You might want to re-assess why is it that you are seemingly so emotionally invested in saying no to the only technique that has an extremely low death count per TWh

I'm not saying no to nuclear. I'm saying "no" to ascientific claims about "physics" and "energy density."

Re: Ultra Safe Nuclear

#185

Post by rtx » Thu, Sep 17, 2020, 9:14 PM UTC

V6HBGNQHU wrote: post #55

nimish wrote: post #18

Safety is no longer the reason Nuclear is not worth it. The sun is a giant, free nuclear fusion plant in the sky. We can capture 1/5th of its output per square meter. For free! The wind -- caused by solar heating -- also generates free power. The cost of harvesting it is now so low, and will always continue to decline as any technology will, that any fuel-based generation mechanism is going to be rendered uneconomic…

Land usage is a big factor. Most people are interested in solar because they care about the environment so taken up vast swathes of land for all the solar panels, destroying habits, is counter productive. Another downside of solar or wind is that it is intermittent and thus will require massive battery systems or alternative conventional power plants to provide energy the rest of the time.

Thanks for bringing up these two points. I have heard people saying lets put solar plats in deserts. They don't realize the deserts also have an Ecosystem.

Re: Ultra Safe Nuclear

#186

Post by TeMPOraL » Thu, Sep 17, 2020, 9:15 PM UTC

z8rHZM8Svhu8hE2 wrote: post #161

steeve wrote: post #28

Earlier quoted context omitted.

A few hints: - read about CIGEO - nuclear waste, once it has decayed, becomes metal in glass - nuclear waste is _small_, see [1], the nuclear fuel waste is the tiny red cube. - wind turbines have a 20 years lifespan, after which the blades are buried and forgotten, and will stay there forever [2] - renewables are more CO2 intensive than nuclear, fuel cycle included, see IPCC reports (there is a debate for nuclear vs…

- wind turbines have a 20 years lifespan, after which the blades are buried and forgotten, and will stay there forever Nuclear power plants have a lifespan of about 50 years, after which the reactor and other parts will be radioactive. This waste must be buried, will be forgotten and will remain there forever.

Now compare the space taken by the buried reactor facility and produced waste, with equivalent number of buried wind turbine blades for the same amount of energy produced :).

Re: Ultra Safe Nuclear

#187

Post by merb » Thu, Sep 17, 2020, 9:16 PM UTC

s9w wrote: post #96

merb wrote: post #31

Earlier quoted context omitted.

1. How long does it need to be kept safe? 2. How to find a storage facility that can keep it safe that long? 3. How to ensure that a facility does not contamine other stuff in X years? 4. if it is recycable why does nobody do it? 5. if it is so easy to store it safe, why does not country have a TRUE final depot? yeah coal is bad, but why compare it to coal in the first place when we want to reduce such things anyway?…

In Germany we have a thing called Ewigkeitskosten ("eternal costs"). That's how we call the expenses that still arise as a consequence from the coal mining operations, especially in the west of Germany. That are things like constantly pumping around water. About a fifth of the western coal region would be underwater without it. They're called that way because we already knew that they will never go away. That was acc…

I'm german. and yes I know about that. It's even worse that our politics fought that it is a good idea to keep coal alive that long, worse we keep lignite alive that long, which is probably even worse than anything on the market. (we are the biggest in lignite and it's the worst thing you can do to your environment. Hambacher forst is a eyesore for our country [1])

but as already said it should not be a tradeoff between coal or nuclear. I do not doubt that nuclear is better than coal, I doubt that nuclear OR coal is the solution we should target at the moment.

[1] https://www.google.com/maps/place/Hambacher+Forst/@50.907264...

Re: Ultra Safe Nuclear

#188

Post by rtx » Thu, Sep 17, 2020, 9:17 PM UTC

hairytrog wrote: post #156

Two interesting things to see here, of many. They are really planning the sites to be temporary compared to the solar/wind/ and other industrial power plants that have little or no plan for returning their sites to the original virgin soil. And two, they seem to use a molten salt loop like in concentrated solar to meet variable demand without changing the power level of the reactor, which you can't really do because…

Great point, power density should be calculated based on land usage.

Re: Ultra Safe Nuclear

#189

Post by hairytrog » Thu, Sep 17, 2020, 9:17 PM UTC

simonebrunozzi wrote: post #179

hairytrog wrote: post #156

Two interesting things to see here, of many. They are really planning the sites to be temporary compared to the solar/wind/ and other industrial power plants that have little or no plan for returning their sites to the original virgin soil. And two, they seem to use a molten salt loop like in concentrated solar to meet variable demand without changing the power level of the reactor, which you can't really do because…

> which you can't really do because of Xenon poisoning Can you clarify this part? You mean that channging the power level of the reactor would cause Xenon poisoning?

I highly recommend HBO's Chernobyl. Explains a lot this stuff. Basically, as a nuclear reactor operates, it is turning the Uranium into lots of other stuff. One component of this other stuff is Xenon-135, which absorbs neutrons and basically gets in the way of nuclear reactions. This is not an issue if you keep the reactor on because there are enough neutrons to keep things going and overcome the Xenon absorption. But if you turn the reactor off, you now have no neutrons from the fission reactions and lots of neutron absorbers. There is so much absorption that it's impossible to start up the reactor for a couple of days. That's why nuclear reactors operate at constant power and only turn off to refuel. This MMR also operates at constant power, which would also have benefits for cycling issues, and uses the molten salt loop to store heat and then use it when it's needed.

Re: Ultra Safe Nuclear

#190

Post by rtx » Thu, Sep 17, 2020, 9:18 PM UTC

lmilcin wrote: post #155

manfredo wrote: post #17

Earlier quoted context omitted.

Because it's not a problem. There's actually very little of it. It occupies a volume the footprint of a football field and 10 yards high [1]. Storing it is pretty foolproof: bury it in an area with no aquifer. The main risk of contamination is getting into the groundwater. If there's no groundwater the risk of contamination is eliminated even if the containers decay over time. And lastly, it doesn't make sense to bur…

Yeah, exactly. Even though it is costly to deal with, per kilogram, there is very little of it when compared to amount of energy produced. An atomic plant might use couple dozen tonnes of fuel which is peanuts compared to the amount of waste from coal power plant. There are no technical problems with storage that we can't solve. The biggest problem is that nobody wants it around.

There is no problem at all. Even a nuclear disaster is less harmful than the pollution we currently releasing in the atmosphere.