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Comment by oceanplexian | Hacker News Reader

There are approximately 6.5e13 tonnes (65 trillion) of Uranium in the Earth's crust, which smarter people than me have determined could power humanity's needs for more than 4 billion years.

That sounds more "renewable" than Solar, which depends on a Star that is due to burn out in 4 billion years and is conventionally branded as "renewable". Not including the ample amount of fissionable material on the Moon and in the immediate Solar System. So I agree, we need to invest heavily into renewables, specifically the one that is right in front of our face, Nuclear.

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This is off by 6 orders of magnitude?

A crucial part here is that you're interested in recoverable Uranium at a reasonable price level. Assuming < USD260/kg, you'll end up at ~8 million tonnes (depending on what other factors you account for): https://www.oecd-nea.org/upload/docs/application/pdf/2020-12...

And so the time estimate is similarly off. Uranium resources can power humanity's need for ~130, years, extending to 250 years if the entire conventional resource base is exploited. (pg. 113 in the report I linked). With large error margins for Uranium deposits not found yet, but not "factor of millions" error margins.

That doesn't mean we shouldn't invest into nuclear (we definitely should), but it does mean that it's not the panacea it's touted as either.

20 years ago we were told there was 20 years of petrol remaining. It's sadly false.

> 20 years ago we were told there was 20 years of petrol remaining. It's sadly false.

No, we weren't. At least not by anyone credible.

Asteroid mining seems like it would become a necessary endeavor once uranium becomes too expensive to extract on earth. I'd bet big that humanity can figure out profitable asteroid mining within the next 100 years!

> Asteroid mining seems like it would become a necessary endeavor (...)

...or, I don't know, add a wind turbine somewhere?

Huh, you must me lucky enough to live somewhere that the wind always blows and the sun always shines.

> Huh, you must me lucky enough to live somewhere that the wind always blows and the sun always shines.

This blend of puerile argument had been thoroughly refuted for over 30 years. Please find another cliche to parrot.

As long as energy storage is expensive this is a valid argument.

And as we erode our base generation in favor of these intermittent sources it becomes a more serious problem.

No it doesn't. Its totally unnecessary and there are many much cheaper ways to get fertile material.

There is also plenty of thorium easily recoverable. The primary problem is that we need to move on to next generation reactors. Fertile martial availability is really not the problem and will not be for a very long time.

With a thermal breeder design reactors we easily have 1000s of years of material.

And in fact volcanic activity will push new thorium up as well. The idea that we can run out of fertile material is mostly just not relevant.

That is assuming slow nuclear reactors, which is the case for the majority of the current reactors. But with fast reactors, you gain a factor of about 100, so the 200 years turn into 20000 [1]

    The big picture effect is that U238 is usable as fuel instead of just U235. There is over 100x more U238 in nature than U235, so the time that 200 years of uranium can last humanity turns into 20,000.

[1] https://whatisnuclear.com/fast-reactor.html

Now count the combined energy of the global wind or total solar irradiation.

Further adding cost to the already most expensive energy source to extract trace amounts of fuel is nonsensical.

Except wind and solar are intermittent, and require burning fossil fuels during periods of non production. Thus, wind and solar still contribute to climate change indirectly, due to their dependency on fossil fuels. This will continue to be the case until some massively scalable storage solution is developed, which remains unsolved.

> That sounds more "renewable" than Solar, which depends on a Star that is due to burn out in 4 billion years and is conventionally branded as "renewable".

Thinking in more immediate time scales (say, the next 100 years), isn't it also a matter of logistics and qualifications needed to operate various types of powerplants and maintain them, navigating the minefield that is the public opinion and minimizing the risks associated with each form of energy production?

Ergo, nuclear is definitely the future, but right now we should also embrace other forms of energy (sun, wind etc.) while we perfect reactor designs, especially in countries where the conditions aren't ideal for nuclear (for example, harsh nature conditions, or not high enough amount of local specialists, or lower budgets in poorer nations, like mine).

Sun and wind seem more scalable, when you're looking into scaling downwards, especially in the cases of more decentralized power grids. Of course, this probably doesn't apply as much to huge metropolitan areas and cities that probably have populations that are greater than that of my entire country.

I always wondered if we could just shoot spent fuel into the sun to get rid of the storage problem here on earth

Then you'd enjoy watching videos on YouTube about why shooting things into the Sun is enormously energy intensive even by the standards of putting things in space and sending them around the Solar System.

Boils down to: getting something to fall into the Sun requires stripping the speed of Earth's rotation around the Sun off the vector. This is... expensive.

Well shot it into space then :) since that is less energy intensive it can get lost in the vast emptiness.

We could also get rid of the storage problem by realizing it isn’t a problem to store a relatively tiny amount of solid waste. The irrational fear of it is mind boggling considering the vast quantities of dangerous gases and particulates we vent into the open air that we breathe without a second thought. I’d much rather have all of our energy by products in solid form safely contained and buried deep under the earth.

Or we know we could dedicate 1 football field of space to it and stop thinking about it so much.

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