List of small modular reactor designs
s are much smaller than the current nuclear reactors and have compact and scalable designs which propose to offer safety, construction, and economic benefits, and offering potential for lower initial capital investment and scalability.
Summary table
The stated power refers to the capacity of one reactor unless specified otherwise.Reactor designs
ACP100: China
In 2021, construction of the ACP100 was started at the Changjiang Nuclear Power Plant site in Hainan province. Previously, in July 2019 CNNC announced it would start building a demonstration ACP100 SMR by the end of the year. Design of the ACP100 started in 2010 and it became the first SMR project of its kind to be approved by the International Atomic Energy Agency in 2016. It is a fully integrated reactor module with an internal coolant system, with a two-year refuelling interval, producing 385MWt and about 125MWe. The 125MWe pressurised water reactor is also referred to as the Linglong One and is designed for multiple purposes including electricity production, heating, steam production or seawater desalination.ARC-100: US/Japan
The ARC-100 is a 100MWe sodium cooled, fast-flux, pool-type reactor with metallic fuel based on the 30-year successful operation of the Experimental Breeder Reactor II in Idaho. ARC Nuclear is developing this reactor in Canada, in partnership with GE Vernova Hitachi Nuclear Energy, with the intent of complementing existing CANDU facilities.Bharat Small Reactor: India
India announced in 2024 their intention to develop an SMR design called the Bharat Small Reactor.CAREM: Argentina
Developed by the Argentine National Atomic Energy Commission & INVAP, CAREM is a simplified pressurized water reactor designed to have electrical output of 100MW or 25MW. It is an integral reactor – the primary system coolant circuit is fully contained within the reactor vessel.The fuel is uranium oxide with an enrichment of 3.4%. The primary coolant system uses natural circulation, so there are no pumps required, which provides inherent safety against core meltdown, even in accident situations. The integral design also minimizes the risk of loss-of-coolant accidents. Annual refueling is required. Currently, the first reactor of the type is being built near the city of Zárate, in the northern part of Buenos Aires province.
Copenhagen Atomics: Denmark
The Copenhagen Atomics Waste Burner is developed by Copenhagen Atomics, a Danish molten salt technology company. The Copenhagen Atomics Waste Burner is a single-fluid, heavy water moderated, fluoride-based, thermal spectrum and autonomously controlled molten salt reactor. This is designed to fit inside of a leak-tight, 40-foot, stainless steel shipping container. The heavy water moderator is thermally insulated from the salt and continuously drained and cooled to below 50 °C. A molten lithium-7 deuteroxide moderator version is also being researched. The reactor utilizes the thorium fuel cycle using separated plutonium from spent nuclear fuel as the initial fissile load for the first generation of reactors, eventually transitioning to a thorium breeder.Elysium Industries
Elysium's design, called the Molten Chloride Salt, Fast Reactor, is a fast-spectrum reactor meaning the majority of fissions are caused by high-energy neutrons. This enables conversion of fertile isotopes into energy-producing fuel, efficiently using nuclear fuel, and closing the fuel cycle. In addition, this can enable the reactor to be fuelled with spent nuclear fuel from water reactors.Flibe Energy: United States
Flibe Energy is a US-based company established to design, construct and operate small modular reactors based on liquid fluoride thorium reactor technology. The name "Flibe" comes from FLiBe, a Fluoride salt of Lithium and Beryllium, used in LFTRs. Initially 2050MW version will be developed, to be followed by 100MWe "utility-class reactors" at a later time. Assembly line construction is planned, producing "mobile units that can be dispersed throughout the country where they need to go to generate the power." Initially the company is focusing on producing SMRs to power remote military bases. Flibe has also been proposed for use in a fusion reactor both as a primary coolant and to breed Tritium fuel for D-T reactors.HTR-PM: China
The HTR-PM is a high-temperature gas-cooled pebble-bed generation IV reactor partly based on the earlier HTR-10 prototype reactor.The reactor unit has a thermal capacity of 250MW, and two reactors are connected to a single steam turbine to generate 210MW of electricity. Its potential applications include direct replacement of supercritical coal-fired power plants, while its heat could be used for seawater desalination, hydrogen production, or a wide range of other high temperature uses in industry.
Hyperion Power Module (HPM): United States
A commercial version of a Los Alamos National Laboratory project, the Hyperion Power Module is a LMR that uses a Pb–Bi coolant. It has an output of 25MWe, and less than 20% enrichment. The reactor is a sealed vessel, which is brought to the site intact and removed intact for refueling at the factory, reducing proliferation dangers. Each module weighs less than 50 tons. It has both active and passive safety features.Integral Molten Salt Reactor (IMSR): Canada
The IMSR Plant is a 2x195 MWe / 2x442 MWt SMR plant design being developed by Terrestrial Energy based in Oakville, Canada.The reactor is proprietary molten salt reactor design that builds on two existing designs: the Denatured Molten Salt Reactor and Small Modular Advanced High Temperature Reactor. Both designs are from Oak Ridge National Laboratory. The key technology of the IMSR® is the integration of the primary reactor components, the moderator, primary heat exchangers and pump into a sealed and replaceable vessel, the IMSR® Core-unit, which is replaced every 7 years. This solves the material lifetime challenges commonly associated with graphite moderators and molten salt use.
The thermal spectrum, graphite moderated, fluoride molten salt reactor, is fueled with Standard Assay low-enriched uranium dissolved in molten fluoride-based salt. It is the only reactor in the Generation IV class that uses Standard Assay LEU fuel. Use of standard fuel simplifies licensability and international acceptance. The Canadian Nuclear Safety Commission completed its Pre-Licensing Vendor Design Review of the IMSR Plant design in April 2023.
International Reactor Innovative & Secure (IRIS): United States
Developed by an international consortium led by Westinghouse and the nuclear energy research initiative, IRIS-50 is a modular PWR with a generation capacity of 50MWe. It uses natural circulation for the coolant. The fuel is a uranium oxide with 5% enrichment of that can run for five years between refueling. Higher enrichment might lengthen the refueling period, but could pose some licensing problems.Iris is an integral reactor, with a high-pressure containment design.
Modified KLT-40: Russia
Based on the design of nuclear power supplies for Russian icebreakers, the modified KLT-40 uses a proven, commercially available PWR system. The coolant system relies on forced circulation of pressurized water during regular operation, although natural convection is usable in emergencies. The fuel may be enriched to above 20%, the limit for low-enriched uranium, which may pose non-proliferation problems. The reactor has an active safety system with an emergency feedwater system. Refueling is required every two to three years. The first example is a 21,500 tonne ship, the Akademik Lomonosov launched July 2010. The construction of the Akademik Lomonosov was completed at the St. Petersburg shipyards in April 2018. On 14 September 2019, it arrived to its permanent location in the Chukotka region where it provides heat and electricity, replacing Bilibino Nuclear Power Plant, which also use SMR, of old EGP-6 design, to be shut down. Akademik Lomonosov started operation in December 2019.mPower: United States
The mPower from Babcock & Wilcox is an integrated PWR SMR. The nuclear steam supply systems for the reactor arrive at the site already assembled, and so require very little construction. Each reactor module would produce around 180MWe, and could be linked together to form the equivalent of one large nuclear power plant. B&W has submitted a letter of intent for design approval to the Nuclear Regulatory Commission. Babcock & Wilcox announced on February 20, 2013 that they had contracted with the Tennessee Valley Authority to apply for permits to build an mPower small modular reactor at TVA's Clinch River site in Oak Ridge, Tennessee.In March 2017 the development project was terminated, with Bechtel citing the inability to find a utility company that would provide a site for a first reactor and an investor.