Uranium: Fluctuation in time
Why reactors shrug off short mining disruptions
What this tab covers How availability changes over seconds, days, seasons, years and longer, how predictable it is, and what that means for the plants that use it.Fission fuel gives very steady output: reactors run near full power for long periods between refuelling outages. The variability that matters is in the mining and market cycle, and in very slow depletion over decades.
Variation by time scale
| Time scale | What happens | How large |
|---|---|---|
| Hours to months | Reactors run at near-constant output, interrupted mainly by planned refuelling8 | World average capacity factor 83% in 2024; over 60% of reactors above 80% |
| Years (supply chain) | Mine output responds slowly to price and policy; stockpiles buffer the gap9 | Production 49,490 tU (2022) and 54,345 tU (2023), rising to 60,213 tU in 2024 according to the World Nuclear Association |
| Decades (demand) | Demand could more than double by 2050 under high growth, or rise 45% in a low case9 | Primary supply meets low demand to 2031; a shortfall is possible from around 2027 under high demand |
| Decades (depletion) | Known resources sufficient through 2050 and beyond, provided exploration and mine investment continue5 | Exploration and mine development spending USD 800 million in 2022 |
| Geological | Uranium and thorium decay very slowly, keeping the stock almost constant over human history10 | Decay of uranium and thorium supplies about 20 TW of the Earth's internal heat |
How predictable it is
High for output: reactor fuel is loaded years in advance and stockpiles hold several years of demand. Supply risk is geopolitical and investment-driven rather than physical, since mining is concentrated in a few countries.
Capacity factors and utilisation
| Plant or measure | Value |
|---|---|
| World nuclear fleet average, 2024 | 83%8 |
Because fuel is cheap relative to plant cost, nuclear plants run as continuously as possible, and the main variation is planned refuelling outages. Civil stockpiles are large (about 42,000 tU in the US, 40,000 tU in the EU and 65,000 t in East Asia at end-2024), so short disruptions to mining do not stop reactors.
Over decades, production has swung with prices and policy, and Kazakhstan's rise through cheap in-situ leaching transformed supply. Thorium remains mostly a by-product of rare-earth mining and is not yet used commercially as fuel.
Sources
- Sufficient uranium resources exist, however investments needed to sustain high nuclear energy growth (Uranium 2024: Resources, Production and Demand) OECD Nuclear Energy Agency, 2025
- Record-breaking year for nuclear electricity generation (World Nuclear Performance Report 2025) World Nuclear News, 2025
- Invest now to secure long-term uranium future, Red Book says World Nuclear News, 2025
- Radioactive decay fuels Earth's inner fires (KamLAND geoneutrino results) ScienceDaily / Lawrence Berkeley National Laboratory, 2011