Resolves as YES if there is strong evidence that the United Kingdom has at least 10 working small modular nuclear reactor (SMR) units before January 1st 2040.

For this market:

• “SMR” definition:

  • A reactor counts as an SMR if its electrical capacity is ≤ 300 MWe, in line with common IAEA / industry definitions, or if it is explicitly described as a “small modular reactor” (or “advanced modular reactor”) by the UK government, the operator, or major international nuclear bodies.

  • Only fission reactors count. Fusion devices do not count.
    

• “Working” definition:
  A reactor unit counts as working once all of the following are true:

  1. The unit is fully built, fuelled, and has received all regulatory approvals required for operation.

  2. It has either:

     • been connected to the electricity grid and delivered net electrical output beyond initial commissioning tests, or

     • provided non‑test process heat (e.g., to industry, district heating, hydrogen production) in normal operation.

  3. It has successfully operated in this way for at least 72 cumulative hours.

  Alternatively, if the operator, regulator, or an authoritative database (e.g., IAEA PRIS‑style listings) classifies the unit as being in commercial operation, it will be treated as working.
  

• What is being counted:

  • The market cares about the number of distinct reactor units, not sites or total GW.

  • Multi‑module plants count each module separately as long as it meets the “working” criteria.

  • A reactor only needs to meet the criteria once before 1 Jan 2040 to count; it may later be shut down or mothballed and still be counted.
    

• Geographic scope:

  • Reactors must be located within the United Kingdom (England, Scotland, Wales, Northern Ireland) or its territorial waters, and fall under UK nuclear regulation.

  • Reactors overseas that are owned or partly financed by UK entities do not count.
    

• Ownership, purpose, and technology:

  • Ownership (public, private, foreign, or mixed) does not matter.

  • Both grid‑connected power reactors and non‑grid SMRs (e.g., industrial or district‑heating units) can count, as long as they meet the “working” criteria.

  • Demonstration or first‑of‑a‑kind plants count if they meet the same criteria; they do not need to be fully commercial projects in the traditional sense.
    

• Resolution sources and timing:

  • The resolver will rely on public information such as UK government and regulator publications, operator press releases, recognised nuclear data sets, and credible international / national news coverage.

  • The market can resolve YES early if there is clear evidence that 10 or more qualifying SMR units have met the “working” criteria before 2040.

  • If it is still uncertain on January 1st 2040 whether the threshold has been met, the market will resolve once sufficient evidence becomes available, using the criteria above.
    
    

Edge cases and disputes will be resolved by applying the spirit of the market: counting genuine, operating SMR units in the UK, not just plans, partial builds, or rebranded projects.