# NuclearChain

> The world nuclear reactor fleet and the fuel chain that supplies it. 1825 reactor units
> across 64 countries, 90 fuel chain facilities from uranium mine to repository, and
> 19 SMR and advanced reactor designs tiered by regulatory position.

Currently 419 reactors are operating worldwide and 85 are under construction.

## What is here that is not elsewhere

Reactor directories are common. What this site adds is the **fuel chain**: which handful of
companies control each stage between a uranium mine and a fuel assembly, with world capacity and
concentration figures per stage. Five plants on earth convert uranium to UF6; four organisations
hold effectively all enrichment capacity. Every reactor page links to the fabricators that can make
its specific assembly and the enrichers upstream of it.

## Data provenance and its limits

- Fleet data derives from the Global Nuclear Power Tracker, Global Energy Monitor,
  August 2026 release, licensed CC BY 4.0.
- **Important caveat:** 93% of units that release lists as operating were last researched in
  May 2024. Every reactor page and data row carries `date_last_researched`. Where a record has
  been corrected against a later source, the correction, its source and its verification date are
  shown on the page.
- Fuel chain data is hand-curated from agency reports and company filings. Every capacity figure
  carries the year it applies to and a link to its source.
- Where a value is not publicly disclosed it is null and renders as "not disclosed". It is never
  estimated, interpolated or filled with a plausible guess.
- Only gross capacity is complete across the fleet; net capacity is populated for about 40% of
  units, so totals use gross.
- US daily reactor status comes from the NRC and is public domain. That feed carries **no outage
  reason**, so outage pages report duration and depth only.

## Key pages

- [Fuel chain overview](https://nuclearchain.net/fuel/): the seven stages and where they narrow
- [Who enriches uranium](https://nuclearchain.net/fuel/enrichment/): world capacity by operator and concentration
- [What HALEU is and where it comes from](https://nuclearchain.net/fuel/haleu/): the constraint on advanced reactors
- [Who converts uranium to UF6](https://nuclearchain.net/fuel/conversion/): the five-plant chokepoint
- [Which SMRs are actually being built](https://nuclearchain.net/smr/): designs tiered by regulator action
- [Every nuclear reactor in the world](https://nuclearchain.net/reactors/): filterable index of all 1825 units
- [US reactor status](https://nuclearchain.net/status/): daily power level per US unit
- [Nuclear power by country](https://nuclearchain.net/countries/)
- [Reactor types explained](https://nuclearchain.net/types/)

## Machine-readable data

All under CC BY 4.0 at [https://nuclearchain.net/data/](https://nuclearchain.net/data/):

- https://nuclearchain.net/data/reactors.csv
- https://nuclearchain.net/data/facilities.csv
- https://nuclearchain.net/data/companies.csv
- https://nuclearchain.net/data/smr-designs.csv
- https://nuclearchain.net/data/supplies.csv
- https://nuclearchain.net/data/fuel-chain.json
- https://nuclearchain.net/api/status.json (live US reactor status, public domain)

Every reactor page has a JSON representation at `/reactors/<slug>.json`.

## Attribution

If you use this material, cite: NuclearChain (nuclearchain.net), CC BY 4.0, and for fleet data
Global Energy Monitor, Global Nuclear Power Tracker, August 2026 release.