Small Modular Reactors and advanced reactor demonstration

Why is this gap important?

While nuclear development has focused on constructing larger reactors in recent decades (typically light-water reactors [LWRs] of 1 400 megawatts electrical [MWe] to 1 750 MWe) to meet growing power demand within large-scale electricity grids, it has been recognised that future energy systems will also require different technologies. Smaller – perhaps more flexible – reactors will be needed for niche markets (small grids, isolated communities, or grids with large shares of variable renewables), to replace fossil fuel-based power plants in the 300 MWe to 600 MWe range, or to provide (in addition to electricity) low-carbon heat that can substitute for fossil fuel uses (desalination, process steam for industry, hydrogen production) or to burn nuclear waste. Advancing the design, certification and demonstration of SMRs and other advanced reactors such as Gen IVs for electric and non-electric applications will offer clean, low-carbon energy generation technologies to complement renewables and CCS.

In addition, countries with long-term policies to close the nuclear fuel cycle loop by multi-recycling nuclear materials are also maintaining efforts to develop Gen-IV fast-reactor designs (particularly sodium fast reactors) and the associated nuclear fuel cycle facilities.

Finally, countries with long term policies to close the nuclear fuel cycle with the multi-recycling of nuclear materials are also maintaining efforts for the development of Gen-IV fast reactor designs (in particular Sodium Fast Reactors) and associated nuclear fuel cycle facilities.

Technology solutions

Most SMR designs of LWR technology use proven technologies, for which the supply chain can be easily adapted. The first examples of SMRs, such as the innovative NuScale design in the United States, the CAREM reactor in Argentina and the KLT‑40S floating nuclear power plant in Russia, are expected to begin operating in the 2020s (TRL 4-7).

Reactor technologies using other coolants (e.g. helium, sodium or molten salts), such as those developed within the Generation IV International Forum or by private companies, are being demonstrated with prototypes in operation or under construction in Russia and China (TRL 4-7).

Coupling to non-electric applications is being investigated (e.g. hydrogen production with Japan’s high-temperature test reactor) but more efforts are needed to demonstrate industrial-scale generation of electricity and process steam (TRL 3-4).

Small modular reactors: NuScale design (US) Readiness level:

CAREM reactor (Argentina) Readiness level:

KTL-40S floating nuclear power plant Readiness level:

Advanced reactors: HTR-PM (China, helium coolant) Readiness level:

Colored bars represent the Technology Readiness Level (TRL) of each technology. Learn more about TRLs

What are the leading initiatives?

  • China: ACP100 SMR scheduled to start construction in 2019, with 125‑MWe capacity by 2025.
  • China: helium-cooled high-temperature reactor HTR-PM (210 MWe), full power operation scheduled for 2020.
  • China: sodium-cooled CFR600 reactor under construction.
  • Canada: SMR roadmap released; CNSC reviewing ten designs, including water-cooled, helium-cooled and molten-salt-cooled technologies. Application for the first micro modular reactor (MMR) received (very small high temperature reactor).
  • Russia: operation of the 800‑MW sodium-cooled BN800 reactor and design of the 1 200‑MW BN1200 reactor.
  • United States: NuScale, a 60‑MWe 12-module LWR SMR plant under licensing by the NRC and planned to be operational in the mid-2020s.
  • France: F-SMR, an innovative 175‑MWe LWR SMR that can be installed with plant configuration of two to six modules is under development by a French consortium.

Recommended actions


Next 5 years:

  • Promote technological neutrality across low-carbon technologies and, more generally, a level playing field in power markets.
  • Promote technology development through financing options and support.
  • Promote international R&D co‑operation to facilitate technology demonstration and licensing.


Next 5 to 10 years:

  • Complete design certification of the most mature designs.
  • Develop harmonised regulatory requirements for advanced reactor technology.
  • Develop factory inspection and testing of modules.


Next 5 years:

  • Complete design and prototype testing.
  • Work with regulators to develop a licensing framework.
  • Develop supply chains and standardisation.
  • Demonstrate safety and reliability of factory-assembled components (compared with on-site).