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echawkes t1_iywbcdh wrote

Reply to comment by [deleted] in Why not use hydrogen and deuterium in fusion reaction rather than tritium and deuterium? by Curious_user4445

It is certainly possible, and experimental reactors have been built to show that it could work.

Sixty or seventy years ago, people thought uranium was scarce, and that we would need breeder reactors (either on thorium/uranium or uranium/plutonium fuel cycles) to make nuclear power viable. However, breeder technology was never fully developed because uranium turned out to be a lot more plentiful and cheap than people expected. There just hasn't been any compelling reason to develop a new technology to make uranium when it's so much easier and cheaper to just dig it out of the ground.

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WazWaz t1_iyx9md4 wrote

Uranium is scarce, but the demand for it is low - known reserves would last about 5 years if it was our only electricity generation method (of course, we'd start using breeders, recycling, etc. if that was the case, and probably find more reserves too).

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echawkes t1_iyxs0g7 wrote

I wouldn't say that uranium is scarce. Significant deposits of uranium are found on every continent (except Antarctica, so far). In a list of the elements that have more than trace quantities in the earth's crust, uranium appears around the middle.

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WazWaz t1_iyzg1py wrote

As I said, if we used it for all our electricity, it would last 5 years. That's pretty scarce, considering how little we use.

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Atechiman t1_iyyywgd wrote

A kilogram of Uranium can generate ~24 terrawatt hours. World reserves of Uranium is 8,000,000 tonnes (8 billion kilograms) . 192 billion terrawatt hours. Worldwide electrical consumption is 23 thousand terrawatt hours.

It would take roughly 6.26 million years to burn through uranium reserves.

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Malkiot t1_iyznf3t wrote

You can't look at world reserves of uranium. You have to look at world reserves of U235 which makes up about 0.76% of all Uranium. You also can't take the total amount, but have to take the commercially viable amount and the amount of energy Uranium contains cannot be converted 1-to-1 to electrical energy.

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>The world's present measured resources of uranium (6.1 Mt) in the cost category less than three times present spot prices and used only in conventional reactors, are enough to last for about 90 years. This represents a higher level of assured resources than is normal for most minerals.

Source: World Nuclear Association an organization promoting nuclear energy.

From our current perspective, when comparing to our previous industrial development, 90 is pretty good. But nowhere near enough in the long term and we'd have to fall back to renewable again unless we use breeder reactors which would improve the sustainabiliy of nuclear or figure out fusion.

So, while nuclear does have some advantages from present knowledge, we may as well skip the 90-year nuclear phase and go for renewables straight away.

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WazWaz t1_iz13knp wrote

And to be clear, that 90 years is at present consumption rate. Nuclear is about 10% of world electricity use, so if it was 100% it would last 9 years. Electrify the road transport sector alone and that comes down to 5 years.

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