Small modular reactors (SMR) are much smaller than the current nuclear reactors (300MWe or less) 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
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 (PWR) 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
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 Hitachi Nuclear Energy, with the intent of complementing existing CANDU facilities.
BWRX-300: United States
A scaled-down version of the ESBWR, that eliminates the possibility of large loss-of-coolant accidents, allowing for simpler safety mechanisms. In January 2020, GE Hitachi Nuclear Energy started the regulatory licensing process for the BWRX-300 with the U.S. Nuclear Regulatory Commission.
CAREM: Argentina
Developed by the Argentine National Atomic Energy Commission (CNEA) & INVAP, CAREM is a simplified pressurized water reactor (PWR) 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 (LOCA). 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 (7LiOD) 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 (MCSFR), is a fast-spectrum reactor meaning the majority of fissions are caused by high-energy (fast) 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.
Encapsulated Nuclear Heat Source (ENHS): United States
ENHS is a liquid metal reactor (LMR) that uses lead (Pb) or lead–bismuth (Pb–Bi) coolant. Pb has a higher boiling point than the other commonly used coolant metal, sodium, and is chemically inert with air and water. The difficulty is finding structural materials that will be compatible with the Pb or Pb–Bi coolant, especially at high temperatures. The ENHS uses natural circulation for the coolant and the turbine steam, eliminating the need for pumps. It is also designed with autonomous control, with a load-following power generation design, and a thermal-to-electrical efficiency of more than 42%. The fuel is either U–Zr or U–Pu–Zr, and can keep the reactor at full power for 15 years before needing to be refueled, with either at 11% or at 13%