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Comment by manquer | Hacker News Reader

Nuclear is carbon clean yes, However it is by far dirtier than any other generation method, if we stop the coal plants today, in few hundred years CO2 levels will revert back and temperatures will normalize. The half life of the radioactive waste is in ten of thousands of years.

We are still struggling store industrial chemicals for mere half dozen years without it causing tragic accidents, while Canada might not be Lebanon today, there is no way to know how well off our future generations will be and whether they can safeguard the waste, both safely and securely from hostile actors without it being an big burden on them .

It will be costly problem at best or a major disaster at worst for all live forms. all this to have some power for 30-40 years.

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If the world continues on a high-emissions trajectory, and people do not later pursue active remediation measures to remove CO2 from the atmosphere, it will take hundreds of thousands of years for natural silicate weathering to draw down atmospheric concentrations to preindustrial levels. More than half will be removed by faster processes, within 1000 years, but a significant minority of the excess will go away over the course of ~400,000 years:

https://www.nature.com/articles/climate.2008.122/figures/1

This is actually longer than the time it will take for the majority of fission products and actinides generated in nuclear fuel to decay. The waste CO2 problem is also distributed over the whole globe rather than easily confined to storage casks like spent nuclear fuel is.

Coal is bad, Co2 is bad, the idea is not the coal is better, we have more than two options, no point in jumping from frying pan into the fire.

Neptuimum-237 has half life of 2.144 Million years and is produced as nuclear fuel waste and one of most mobile nuclides at the Yucca repository. It will take 100's of millions of years for sizeable quantity to go through its decay chain and be safe.

There are safer better options than nuclear to coal. A 1000 year time line of natural restoration is not acceptable and needs to be addressed, but trading it for millions of years is not the right solution.

> "in few hundred years CO2 levels will revert back'

Where do you imagine billions of tons of CO2 will go? It does not have a half-life like nuclear waste, once you've taken that carbon out of the ground, it is here to stay for tens of millions of years. There will never be enough trees to sequester this carbon. We must expend trillions of dollars to reprocess it back into oil or rock-like formations.

Also in the entire history of nuclear industry there has been no credible case of 'hostile actors' coming close to stealing nuclear waste. That's because doing so doesn't make any sense - it is useless to nations, and if someone like Taliban tried to handle it, they'd probably die in the process.

Nuclear waste is not a liquid that might spill and run away if you aren't careful. When properly handled it is vitrified in solid glass, and it doesn't go anywhere. Sweden is placing it in underground storage in solid rock, in a region that's geologically stable for millions of years - it will never bother anyone again or cost a penny more.

>However it is by far dirtier than any other generation method,

Where do you think the fancy chemicals in the fiberglass turbines or the exotic metals in the solar panels comes from?

>We are still struggling store industrial chemicals for mere half dozen years without it causing tragic accident

Oh boy are you going to love the high tech chemical industry that underpins the manufacture of wind turbines and solar panels.

All these things are dirty if you don't clean up after them. Nuclear is pretty clean just by virtue of how little material you need to process per kilowatt. A kilo of uranium gets you a lot more energy than a kilo of turbine or a kilo of solar panel.

They're all better than fossil fuels because they don't crap byproducts into the atmosphere but you need to have so much less underlying industry per energy generated with nuclear that it's just inherently cleaner than anything else. This is assuming that you're cleaning up after whichever one you choose.

If you fully recycle the nuclear waste, the radioactivity drops to that of natural uranium ore in about 500 years: https://whatisnuclear.com/waste.html

Radioactive waste with half lives of tens of thousands of years is by definition not particularly radioactive. It is however reasonably well contained; roughly a truck load in a year. Where as CO2 is defused through the atmosphere in a way which makes it very difficult to recapture.

> Radioactive waste with half lives of tens of thousands of years is by definition not particularly radioactive

Sure plutonium-239 with half life of 24,000 is not particularly radioactive, neptunium-237 has half live of more than 2 million years, both are extremely dangerous to humans for multiples of that time.

Half live is not directly related to the level of damage gamma decay can do to you. Elements are perfectly capable of emitting hazardous amounts of radiation for thousands and millions of years time.

We cannot barely build a phone to last 3 years, The incentive to not create problems for future generations is simply not there. If it was, we would doing a lot more for pollution and plastics and the mass extinction event we are currently causing.

I don't believe our track record as a species warrants any trust on the ability to build containment to last thousands of years.

Plutonium-239 is an alpha emitter. Nuclear missiles on submarines actually have to spend more money to create highly pure Plutonium-239 specifically because it's long half life means it has a low rate of spontaneous emissions. This makes it safer for crew who have to live and work in close quarters with these missiles.

The double standard against nuclear always amuses me. If we truly want it to be similar to fossil fuels, we can just wait a couple hundred years for nuclear waste to cool down, take it out, grind it into a fine powder, and literally spew over the globe, and it will barely register on anything other than Geiger counters.

Meanwhile, fossil fuels generate so much waste per kWh that it's impossible to contain it, so we just spew it over the globe at day one, changing the Earth's climate and driving mass extinction (and killing a million per year), but it's OK, because if stop using fossil fuels today and wait a few hundred years then things will be back to normal. Maybe.

The double standard for nuclear worries me.

Of all the ideas on nuclear waste disposal including launching on rocket into the sun, this is the most dangerous[1].

Firstly If you are replacing Coal and other methods of energy generation with Uranium the amount of waste is not small anymore ( it already is not small in any sense).

Cooling down the temperature is not the only problem. Neptunium-237 has half life of 2Million years!, plutonium 239 of more than 24,000 years, these materials will be radioactive for a longer time than we as species have been on this planet. Grinding them fine and spreading them everywhere may very well kill all life on this planet for ten of millions of years, it may never come back.

Coal is bad, nobody is saying it is better than nuclear, but replacing coal with nuclear is opening a whole new can of worms, we are not equipped to handle, there are plenty of other safer alternatives .

[1] In in interest of a civil discussion, I will leave it at that.

Appreciate the civil discussion, so let me just say that I suspect you never typed in the numbers and tried to quantify the danger of nuclear waste. Let's try a quick and rough estimate.

The energy density of uranium is roughly 80,620,000 MJ/kg [1]. Existing nuclear power plants have thermal efficiency between 30-40%, roughly speaking [2], so let's be pessimistic and choose 30%. That means actual usable energy density of uranium is 24,186,000 MJ/kg, or 6,718,333 kWh/kg.

The world produced 27,644,800 GWh = 27,644,800,000,000 kWh of electricy on 2019 [3]. If we used nuclear to generate all of this, we'd need 4,114,830 kg of uranium, or 4,115 ton per year. Let's round up to 5,000 ton.

Spent nuclear fuel contains about 0.8% plutonium 239 [4], so our 5,000 ton of uranium will generate about 40 ton of plutonium 239, with half-life 24,000 years and radioactivity of 2.3 GBq/g [5]. So our hypothetical nuclear waste will have radioactivity of 2.3 GBq/g * 40 t = 92 PBq. Which is a lot.

...or is it?

Potassium, naturally occurring and essential for life, is naturally radioactive (31 Bq/g), because it contains 0.012% K40 [6]. Seawater is about 0.04% potassium [7], which contributes to a natural radioactivity of 12.4 Bq/kg, or 12.4 kBq/t from potassium alone.

Actually, let's forget the earth. Let's spread the nuclear waste evenly on the Mediterranean - volume 3,750,000 km^3 [8] - who needs Italy anyway?

It contains 3,750,000,000,000,000 ton of seawater, or 46,500,000,000,000,000 kBq of natural radioactivity, which is 46,500 PBq. So our hypothetical dump of plutonium 239 will increase the Mediterranean sea's natural radiation level by about 92/46500 = 0.2% per year [9].

A far cry from extinction of all known life, I have to say.

* By the way, you may want to re-consider before saying stuff like "Pu239 has half-life of 24,000 years - it's not safe!" Coal, for example, contains tons of mercury, which is not radiactive (i.e., it has a half-life of infinity). After 24,000 years, there will be 50% of Pu239, but 100% of mercury left from coal ashes. Which is worse?

[1] https://en.wikipedia.org/wiki/Energy_density

[2] https://www.world-nuclear.org/information-library/current-an...

[3] https://en.wikipedia.org/wiki/List_of_countries_by_electrici...

[4] https://en.wikipedia.org/wiki/Plutonium-239#In_nuclear_power...

[5] https://www.radioactivity.eu.com/site/pages/Plutonium_Proper...

[6] https://en.wikipedia.org/wiki/Potassium

[7] https://en.wikipedia.org/wiki/Seawater

[8] https://en.wikipedia.org/wiki/Mediterranean_Sea

[9] Of course the actual effect will be higher because there will be other isotopes, shorter-lived and more radioactive. That's why I proposed keeping the waste in a fridge for 200 years first. I'm not a monster.

It kills the fewest number of people pre joule and the negative externalities are centralized, i.e., the people that made the mess need to pay to keep it stored safely. I fail to see how an underground bunker of radiation is dirtier than people literally breathing in toxic fumes. Coal even releases a ton of radiation per joule, so even the framing of radioactive vs non-radioactive is a subject of discussion.

Also, I highly doubt that if humanity makes it even a thousand more years that we'll have trouble finding a productive use for depleted uranium or other spent fissile fuels. They have many interesting properties.

The people and the governments who took those decisions will be long gone in few hundred years, the waste will still be here , leaking into the soil and water table.

I was not arguing for coal in any way I am merely pointing saying Nuclear is not as clean as pro nuclear people argue.

Yes the NORM released by Coal and other human activities is substantial, However it is not remotely comparable to Fukishma, Chernobyl and bikini atoll . I don't trust any of the world governments to build a safe reactor and I don't share your optimism on that we will find ways to handle the waste. Instead of trusting luck that we will find clean ways to handle, we can start building plants when we do find them, .

It is recency bias to think we will be able to keep technologically innovating at the same pace we have in the last few decades or even few hundred years, most of our history innovation has happened rapidly only under certain conditions, it may be that those conditions will continue to favour, or maybe physical limits such as moore's law slowing down, resource limits stuck on single planet economically or socio political structural problems can slow down innovation substantially, Any of them could be a great filter in the Fermi Paradox sense.

> the people that made the mess need to pay to keep it stored safely.

We'd certainly like for those people to keep the mess stored safely, but there are incentives for them to not do so, even assuming they had the ability to.

Nuclear waste is so so so small, it's okay for it to last a long time.

And you'd better not ignore how much radiation is released by coal.

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