Under current conditions of extraction, enrichment, use, recycling, and taking into account known reserves, yeah, about 100 years with roughly constant consumption.
But there are adjustment variables at all levels of the fuel cycle:
extraction
enrichment
consumption
recycling
What limits these adjustments is a little technique, a lot of economics: today, uranium costs a pittance, so 0 effort to save it. We only use the richest deposits, we enrich without forcing, we consume without optimizing, we hardly recycle.What would allow these adjustments, it would be a higher cost of uranium ... Exactly when it begins to be made a little more rare. Like the oil where the deposits were more numerous as prices went up. Like any natural resource of stock, in fact (hydrocarbons, metals ...).
And the cool thing about nuclear is that uranium is something like 1-2% of the kWh price paid by the user, in France anyway. On the order of 0,15 cents on 15 cents that costs a kWh ...
So even an increase of one factor 10 on the cost of uranium, it will increase the kWh of a dime and a half over several decades, it is negligible.
If the economic conditions make it possible to envisage parameters of adjustment of the ratio consumption / stock of uranium, which are they?
Exploitation of natural uranium1) Exploit less rich deposits. Very simple, just make sure it stays profitable.
2) Exploiting "secondary deposits": coal ash, mining residues from other mining industries ... Same thing, nothing wizard, just a question of profitability.
These two options make it possible to gain a lot of resources, without changing the orders of magnitude, I think, but without being very expensive.
3) Exploit marine uranium.
Here, we are on a crazy idea, technically complicated (and therefore expensive) to implement, but extract uranium naturally dissolved in seawater would multiply the reserves by ... Many. More info in the thread below.
4) Recover highly enriched uranium or plutonium from nuclear weapons. It has already been done, no technical or economic difficulty, just have countries that disarm ^^
Enrichment
5) It is necessary to enrich more ... In France, when one enriches the uranium, one makes 1 ton of enriched with 3-4% and 7 tons of impoverished with 0,3% from 8 tons of natural with 0,7%.
If enrichment was pushed to reduce the 0,2% depleted content, see 0,1%, then natural uranium would be saved, producing equal enriched uranium.
But enriching is expensive, and natural uranium today costs nothing. We do not get tired, so.
But since the impoverished is not lost but wisely stored at home, we could still draw some more enriched if the need justified, no problem, it is thought for.
Use in reactors
6) Depending on the rate of enrichment, its manufacture, its mode of use, more or less energy can be drawn from one ton of nuclear fuel. Again, the question of economic balance between making the effort or spoiling the U that costs nothing.
And it's not marginal, because by increasing the enrichment a bit (3.5% to 4.5%), we can almost double the amount of energy that can be drawn from a ton of fuel. However, it entails multiple constraints, on the management of the heart and reprocessing. Nothing insurmountable, it has even been done, but it costs.
Reprocessing-Recycling
7) Currently, in France, produces a little more than 10% of our nuclear electricity with recycled fuel, with MOx (plutonium and uranium recovery from spent fuel and manufacture of new fuel with).
On the one hand, we could push this concept further, because today we only recover part of the used uranium to associate it with the plutonium, but we could also recover the rest and re-enrich it. . This is the EDF project, so as to increase to 25% of production based on recycled fuel by the 2025 horizon.
No technical lock, it has already been done on a nuclear power plant before being abandoned ... By economic reason.
On the other hand, recycling, even limited, is far from being generalized to the whole world. So there's a way to take recycling further down the world and save a lot of uranium resources.
So far, apart from marine uranium, I have mentioned fairly modest solutions that play marginally on the order of magnitude. Able to multiply the resources by 2, 3, maybe, I do not know ... But we will finish BIG.
FUCKING breeding. Plutonium, it is recycled once. With fast breeder reactors, we will be able to recycle it many times. And, above all, we will be able to produce astronomical quantities.
Just depleted uranium. We have our breeder reactor breeder, coated with depleted uranium that will absorb the neutrons that will escape from the heart. AND PAF. Neutron, uranium 238, bim, plutonium 239. Well, it's not so simple, but the result is that one.
And suddenly, in France, we end up being able to feed a fleet of breeders millennia, even tens of thousands of years.
Just with the depleted uranium that we already have in stock, purified, stored, ready. Without more need to extract a gram from the ground (once the cycle started, which requires a long transition phase all the same).
And globally, that's the idea too. By adding breeding based not more on uranium, but on thorium (more abundant than the U), it is even more the feast of the underpants.
Well, on the other hand, the overdriven is complicated - feasible, reactors have shown (Phoenix ...) and still show (BN-600, 800 ...) - but complicated. And so expensive at term, very expensive today (because not mature).
A bit like the extraction of the marine U. But suddenly, the day when the uranium reserves start to be a problem, we have 6 variables (to my knowledge) of adjustment to give a little wide ...