The TES-3, a 1.5 MWe PWR mounted on four heavy tank chassis, started up in 1961 at Obninsk. It operated until 1965 and was abandoned in 1969.

In 1976, the Joint Institute for Power Engineering and Nuclear Research in Belarus built two Pamir-630D truck-mounted small air-cooled nuclear reactors during the Soviet era. These reactors were 5 MWt/0.6 MWe HTR reactors using 45% enriched fuel with a zirconium hydride moderator.

The U.S. Army's small reactor program, initiated in the 1950s with eight reactors, faced issues of unreliability and high costs, leading to its shutdown in 1977.

The CAREM25 reactor prototype, a 100 MWt (27 MWe gross) integral pressurized water reactor, was announced by the Argentine National Atomic Energy Commission (CNEA) in 1984. It is designed for electricity generation, research, and water desalination.

The 200 MWt (72 MWe) HTR-modul was designed by Siemens/Interatom as a modular unit with advanced passive cooling features. It was licensed in 1989 but was not constructed.

Siemens/Interatom's HTR-modul design, which was part of the technology bought by Eskom in 1996, served as a direct antecedent of the pebble bed modular reactor (PBMR).

In November 1997, President Bill Clinton ordered his Committee of Advisors on Science and Technology to review the national energy portfolio. This led to recommendations for new reactor designs and lower-output reactors, ultimately resulting in increased funding for nuclear research and development.

Japan Atomic Energy Agency's High-Temperature Test Reactor (HTTR) of 30 MWt began operation at the end of 1998, aiming to develop a thermochemical means of producing hydrogen from water.

In 1999, Idaho National Engineering and Environmental Laboratory (INEEL) and Argonne National Laboratory were designated as lead laboratories for nuclear reactor technology in the U.S. Department of Energy's national laboratory complex.

In 2000, the Nuclear Energy Research Initiative provided funding for a project called the Multi-Application Small Light Water Reactor (MASLWR), involving INEEL, Oregon State University, and Nexant. This project laid the foundation for NuScale's Small Modular Reactor.

The preliminary design stage of the GT-MHR, a nuclear reactor developed by General Atomics in partnership with Russia's OKBM Afrikantov and supported by Fuji, was completed in 2001. However, the programme to construct a prototype in Russia was halted.

In 2003, the US Department of Energy (DOE) published a report on the conceptual design of the Multi-Application Small Light Water Reactor (MASLWR), focusing on natural circulation of coolant. Several integral Pressurized Water Reactor (PWR) designs have similarities to this MASLWR design.

In 2004, the town of Galena granted initial approval for Toshiba to build a 10 MWe (30 MWt) 4S reactor in that remote location. The design aimed to maintain an outlet coolant temperature suitable for power generation and high temperature electrolytic hydrogen production.

In 2006, Westinghouse claimed they could build an AP1000 reactor for as low as $1.4 billion, which is significantly lower than the current cost estimates for similar projects.

In 2007, a team of nuclear scientists at Oregon State University (OSU) invented the first commercial Small Modular Reactor (SMR), which revolutionized the nuclear energy industry by introducing a new concept of modular construction and deployment.

In 2008, NuScale informed the U.S. Nuclear Regulatory Commission of its intention to pursue design certification for a 45 MWe module, either for independent operation or as part of a multi-module facility.

In mid-2009, Babcock & Wilcox (B&W) announced the mPower reactor, a 500 MWt, 180 MWe integral PWR designed for factory manufacturing and rail transportation to site. The design was intentionally conservative to facilitate acceptance and licensing.

In October 2009 and June 2010, the International Atomic Energy Agency (IAEA) held workshops to discuss the establishment of a central licensing system for Small Modular Reactors (SMRs), aiming to enhance nuclear safety guidelines.

In December 2009, AKME-engineering, a joint venture between Rosatom and the En+ Group, was created to develop and construct a pilot SVBR unit. En+ Group, a subsidiary of Basic Element Group, was to provide most of the capital for the project.

Presentation on Small Modular Advanced High Temperature Reactor (SmAHTR) by Sherrell Greene from Oak Ridge National Laboratory at DOE FHR Workshop in September 2010.

In 2011, Fluor Corporation became NuScale's primary investor, bringing significant engineering, fabrication, and construction capabilities to the company. This investment boosted NuScale's development of small modular reactors.

In March 2012, the U.S. Department of Energy (DOE) signed an agreement with NuScale to construct a demonstration unit at the Savannah River Site in South Carolina, marking a significant milestone in the development of Small Modular Reactors.

In April 2012, Westinghouse initiated a project with Ameren Missouri to secure DOE funds for developing the SMR design and obtaining necessary licenses from the NRC for multiple SMRs at Ameren's Callaway site.

In May 2012, Westinghouse partnered with General Dynamics Electric Boat and Burns & McDonnell for design assistance and architectural/engineering support for their small modular reactor project.

In mid-2012, the SMART reactor designed by KAERI received standard design approval from the Korean regulator. It is a 330 MWt pressurized water reactor with advanced safety features and integral steam generators.

By 2012, major revisions led to the initial design of the SMR-160.

A supplement report to the IAEA Advanced Reactors Information System providing updates on the status of small and medium-sized reactor designs.

In November 2012, the US Department of Energy (DOE) declared its support for the accelerated development of the mPower reactor design for early deployment, allocating up to $226 million, with $111 million already paid.

In February 2013, B&W signed an agreement with TVA to build up to four units at Clinch River for the mPower reactor. The agreement included plans for design certification and construction permit application to be submitted to the NRC in 2015.

In May 2013, Westinghouse announced a collaboration with China's State Nuclear Power Technology Corporation (SNPTC) to accelerate the design development and licensing of its Small Modular Reactor (SMR) in the USA and China. SNPTC would ensure that the SMR design met Chinese licensing standards and lead the licensing effort in China.

In mid-2013, NuScale initiated the Western Initiative for Nuclear (WIN), a collaboration involving multiple western states to explore the demonstration and deployment of multi-module NuScale Small Modular Reactor (SMR) plants in the western USA. The project, now known as the Carbon-Free Power Project, aimed to have a demonstration NuScale SMR operational by 2024 at the DOE's Idaho National Laboratory.

In July 2013, CNNC signed agreements for ACP100 projects in Hengfeng county and Ningdu county in Jiangxi province, costing CNY 16 billion. Plans for further inland units in Hunan and possibly Jilin provinces were also discussed, with high export potential and full IP rights.

Westinghouse was expected to submit a design certification application to the NRC in September 2013, but the company postponed it to reassess the market for small reactors.

In December 2013, the Department of Energy (DOE) announced a grant to NuScale on a 50-50 cost-share basis, totaling up to $217 million over five years. The grant aimed to support the design development, NRC certification, and licensing of NuScale's small reactor design, which evolved from 45 MWe to 77 MWe.

In January 2014, Westinghouse announced the suspension of work on its small modular reactors due to insufficient prospects for multiple deployment. The company cited the need for government subsidies to justify the economics of its SMR unless a significant number could be supplied.

In August 2014, TVA announced plans to file an early site permit (ESP) application for one or more small modular reactors at Clinch River instead of a construction permit application. The application was expected by the end of 2015.

In January 2015, Terrestrial Energy announced a partnership with the US Oak Ridge National Laboratory to enhance the design of the IMSR over a two-year period.

In March 2015, KAERI signed an agreement with Saudi Arabia’s King Abdullah City for Atomic and Renewable Energy (KA-CARE) to assess the potential for building SMART reactors in Saudi Arabia. This marked a significant step towards potential international deployment of the SMART reactor.

Efforts by the CORDEL Working Group of the World Nuclear Association to facilitate international licensing of small modular reactors.

In October 2015, Rosatom reported that experts confirmed there were no scientific or technical issues preventing the completion of the SVBR-100 project and obtaining a construction license.

A feasibility study conducted by Hatch Ltd. for the Ontario Ministry of Energy on the potential deployment of Small Modular Reactors (SMRs) in Ontario.

Presentation by Vladimir Artisiuk from Rosatom Technical Academy at the IAEA Technical Meeting on Technology Assessment of Small Modular Reactors for Near Term Deployment in Tunis, Tunisia.

The event discusses the story behind America's first potential small modular reactor, specifically focusing on NuScale LLC and their small modular reactor design.

In January 2019, Terrestrial Energy informed the US Nuclear Regulatory Commission about their plans to pursue design approval for the IMSR-400.

In February 2019, Holtec signed agreements with Exelon and Ukraine's Energoatom to collaborate on building the SMR-160. These partnerships aimed to explore the feasibility of deploying the SMR-160 system in Ukraine and potentially establishing Ukraine as a regional hub for SMR sales in Europe, Asia, and Africa.

In May 2019, the BWRX-300 was submitted to Canada’s CNSC for a pre-licensing vendor design review, marking a significant step in the regulatory process.

In July 2019, the U-Battery consortium became the first design to complete the first phase of Canadian Nuclear Laboratories’ review process for siting an SMR at Chalk River Laboratories in Ontario.

In October 2019, the Canadian Nuclear Safety Commission (CNSC) completed phase 1 pre-licensing vendor design review for the ARC-100 reactor. This marked a significant milestone in the regulatory process for the deployment of the reactor.

In November 2019, CNL announced the selection of Kairos Power, Moltex Canada, Terrestrial Energy, and Ultra Safe Nuclear Corporation (USNC) as the first recipients of support under the Canadian Nuclear Research Initiative. This initiative aims to accelerate the deployment of Small Modular Reactors (SMRs) by facilitating research and development on specific projects.

In December 2019, NuScale submitted its 60 MWe (now 77 MWe) Small Modular Reactor (SMR) design to the Canadian Nuclear Safety Commission (CNSC) for pre-licensing vendor design review, initiating a crucial regulatory process.

In March 2020, Rolls-Royce signed a memorandum of understanding with Turkey's EUAS International ICC to evaluate the technical and economical feasibility of SMRs.

In April 2020, a preliminary safety analysis report for a single unit demonstration plant of the ACP100 reactor at Changjiang, China, was approved.

The world's first floating nuclear power plant, Akademik Lomonosov, started commercial operation in May 2020. It is equipped with two 35 MW(e) Small Modular Reactors (SMRs) and is producing energy.

In June 2020, a joint venture was established between USNC and OPG to develop the MMR project at Chalk River, Ontario. The partnership aimed to provide project development, licensing, construction, and operation services for the project.

In July 2020, the Department for Business, Energy & Industrial Strategy awarded £10 million each to Westinghouse, U-Battery consortium, and Tokamak Energy for their respective modular reactor projects. Additional funding was allocated for manufacturing advanced nuclear parts and strengthening the nuclear regulatory regime.

In August 2020, the design passed the first phase of the Canadian Nuclear Safety Commission’s (CNSC’s) three-phase pre-licensing vendor design review.

In October 2020, the Minister for Innovation, Science & Industry announced a C$20 million investment in Terrestrial Energy to accelerate the development of its Integral Molten Salt Reactor (IMSR). This investment marks the first grant from Canada’s Strategic Innovation Fund towards advancing SMR technology.

In November 2020, Rolls-Royce partnered with companies like Assystem, Atkins, BAM Nuttall, and others to develop SMRs in the UK. They also added US utility Exelon to operate Rolls-Royce SMRs in the UK and abroad.

In December 2020, the DOE selected Holtec for a $147.5 million development programme for the SMR-160 under its Advanced Reactor Demonstration Program.

Presentation by Elena Pashina on Rosatom SMR technology at Energiforsk Annual Nuclear Conference 2021 on Small Modular Reactors.

In February 2022, the Swedish Energy Agency awarded the joint venture funding of just over SEK 99 million ($10.6 million) for their project.

In March 2022, the Canadian government announced an investment of C$27.2 million in the eVinci reactor through Innovation, Science and Economic Development Canada’s Strategic Innovation Fund.

In May 2022, the pouring of concrete for the reactor's basemat of the Linglong One Demonstration Project at Changjiang on Hainan Island was completed.

In October 2022, the Darlington site was licensed for site preparation works, as OPG expects to make a construction decision by the end of 2024 with a preliminary target date of 2028 for plant operations.

In November 2022, Ontario Power Generation (OPG) submitted a construction licence application for a BWRX-300 at the Darlington site.

In December 2022, NuScale announced the completion of the standard generic plant design for the VOYGR plant, which will serve as a starting point for deploying site-specific designs.

Progress in the development of Small Modular Reactor (SMR) technology is discussed, focusing on innovations and advancements in the field.

Westinghouse aims to have the eVinci microreactor ready for commercial deployment by 2025, with plans for design, testing, analysis, and licensing to be completed by 2022 and testing by 2023.

The projected cost of electricity from the SMRs has increased significantly to $89 per megawatt, which is much higher than initially anticipated.

The U-Battery consortium, led by Urenco, has gained UK government support for a prototype with a target operation in 2028.

A demonstration NuScale Small Modular Reactor (SMR) is projected to be operational in 2029 at the DOE's Idaho National Laboratory. Utah Associated Municipal Power Systems (UAMPS) will be the owner and Energy Northwest (ENW) will be the operator.

The GTHTR-300C, based on the HTTR, is being developed with the aim of commercialization around 2030, showcasing advancements in gas turbine high-temperature reactor technology.