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56 Reactors from the IAEA SMR Booklet

Updated: Dec 2, 2022

The IAEA’s Department of Nuclear Energy within its structure contains the Section for Nuclear Power Technology Development tasked to facilitate efforts of Member States in identifying key enabling technologies in the development of advanced reactor lines and addressing their key challenges in near term deployment.

There is increasing interest in small modular reactors (SMRs) and their applications. SMRs are newer generation reactors designed to generate electric power up to 300 MW, whose components and systems can be shop fabricated and then transported as modules to the sites for installation as demand arises.

Most SMR designs adopt advanced or even inherent safety features and are deployable either as a single or multimodule plant. SMRs are under development for all principal reactor lines: water-cooled reactors, high-temperature gas-cooled reactors, liquid-metal, sodium and gas-cooled reactors with fast neutron spectrum, and molten salt reactors.

The key driving forces of SMR development are fulfilling the need for flexible power generation for a wider range of users and applications, replacing ageing fossil-fired units, enhancing safety performance, and offering better economic affordability.

Many SMRs are envisioned for niche electricity or energy markets where large reactors would not be viable. SMRs could fulfil the need for flexible power generation for a wider range of users and applications, including replacing ageing fossil power plants, providing cogeneration for developing countries with small electricity grids, remote and off-grid areas, and enabling hybrid nuclear/renewables energy systems. Through modularisation technology, SMRs target the economics of serial production with a shorter construction time. Near term deployable SMRs will have safety performance comparable or better to that of evolutionary reactor designs.

Though significant advancements have been made in various SMR technologies in recent years, some technical issues still attract considerable attention in the industry. These include control room staffing and human factor engineering for multi-module SMR plants, defining the source term for multimodule SMR plants with regards to determining the emergency planning zone, developing new codes and standards, and load-following operability aspects. Some potential advantages of SMRs like eliminating public evacuation during an accident or a single operator for multiple modules are under discussion with regulators. Furthermore, although SMRs have a lower upfront capital cost per unit, their generating cost of electricity will probably be substantially higher than that for large reactors.

Currently, there are more than 50 SMR designs under development for different application. Three industrial demonstration SMRs are in an advanced stage of construction: in Argentina (CAREM, an integral PWR), in the People’s Republic of China (HTR-PM, a high-temperature gas-cooled reactor) and the Russian Federation (KLT40s, a floating power unit). They are scheduled to start operation between 2019 and 2022. In addition, the Russian Federation has already manufactured six RITM-200 reactors (an integral PWR) with four units already installed in the Sibir and Arktika icebreakers, to be in service in 2020.

The IAEA SMR Booklet provides brief introductory information and technical description of the key SMR designs and technologies under different development and deployment stages.

The 2018 edition comprises six (6) parts arranged in the order of the different types of coolants, the neutron spectrum adopted, and a sixth part (a new category) on other SMRs that do not use the traditional coolants and/or fuel design.

We have listed them below:


Water Cooled Small Modular Reactors (Land Based)

Land-based water-cooled SMRs presents the key SMR designs adopting integral light water reactor (LWR) technologies. This represents the most mature technology since it is like most of the large power plants in operation today.
  • CAREM (CNEA, Argentina)

  • ACP100 (CNNC,China)

  • CAP200 (SNERDI/SNPTC, China)

  • DHR (CNNC, China)

  • IRIS (IRIS, International Consortium)

  • DMS (Hitachi-GE Nuclear Energy, Japan)

  • IMR (Mitsubishi Heavy Industries, Japan)

  • SMART (KAERI, Republic of Korea)

  • ELENA (National Research Centre “Kurchatov Institute”, Russian Federation)

  • KARAT-45 (NIKIET, Russian Federation)

  • KARAT-100 (NIKIET, Russian Federation)

  • RITM-200 (Afrikantov OKBM, Russian Federation)

  • RUTA-70 (NIKIET, Russian Federation)

  • UNITHERM (NIKIET, Russian Federation)

  • VK-300 (NIKIET, Russian Federation)

  • UK SMR (Rolls-Royce and Partners, UK)

  • mPower (BWX Technologies, Inc., USA)

  • NuScale (NuScale Power Inc., USA)

  • SMR-160 (Holtec International, USA)

  • Westinghouse SMR (Westinghouse Electric Company LLC, USA)

Water Cooled Small Modular Reactors (Marine Based)

Marine-based water-cooled SMRs presents concepts that can be deployed in a marine environment, either under water or on a barge. This unique application provides many and more flexible deployment options, but also face many challenges if is to be deployed internationally, i.e. such as permission to cross national and international waters.
  • ACPR50S (CGN, China)

  • ABV-6E (Afrikantov OKBM, Russian Federation)

  • KLT-40S (Afrikantov OKBM, Russian Federation)

  • RITM-200M (Afrikantov OKBM, Russian Federation)

  • SHELF (NIKIET, Russian Federation)

  • VBER-300 (Afrikantov OKBM, Russian Federation)

High-Temperature Gas-Cooled Small Modular Reactors

High Temperature Gas Cooled SMRs provides information on the modular type HTGRs under development and under construction. HTGRs provide high temperature heat (≥750°C) that can be utilized for more efficient electricity generation, a variety of industrial applications as well as for cogeneration.
  • HTR-PM (Tsinghua University, China)

  • GTHTR300 (Japan Atomic Energy Agency, Japan)

  • GT-MHR (OKBM Afrikantov, Russian Federation)

  • MHR-T Reactor/Hydrogen Production Complex (OKBM Afrikantov, Russian Federation)

  • MHR-100 (OKBM Afrikantov, Russian Federation)

  • AHTR-100 (Eskom Holdings SOC Ltd., South Africa)

  • HTMR-100 (Steenkampskraal Thorium Limited, South Africa)

  • PBMR®-400 (Pebble Bed Modular Reactor SOC Ltd, South Africa)


  • Xe-100 (X Energy, LLC - USA)

Fast Neutron Spectrum Small Modular Reactors

Fast Neutron Spectrum SMRs presents the SMRs with fast neutron spectrum with all the different coolant options. In the booklet on “Status of Innovative Fast Reactor Designs and Concepts” (see Annex IV) the four major fast reactor options were described. They are sodium cooled fast reactor (SFR), the heavy liquid metal-cooled (HLMC, i.e. lead or lead-bismuth) fast reactor, the gas-cooled fast reactor (GFR) and molten salt fast reactor (MSFR). In this booklet fast reactor designs with only the first three types of coolant are included, since none of the molten salt fast reactors are SMRs. The MSR designs included all have thermal neutron spectra and are included in part five.
  • 4S (Toshiba Energy Systems & Solutions Corporation, Japan)

  • LFR-AS-200 (Hydromine Nuclear Energy S.àr.l. (HNE), Luxembourg)

  • LFR-TL-X (Hydromine Nuclear Energy S.àr.l. (HNE), Luxembourg)

  • BREST-OD-300 (NIKIET, Russian Federation)

  • SVBR-100 (JSC “AKME-engineering”, Russian Federation)

  • SEALER (LeadCold, Sweden)

  • EM2 (General Atomics, USA)

  • SUPERSTAR (Argonne National Laboratory, USA)

  • Westinghouse Lead Fast Reactor (Westinghouse Electric Company LLC-USA)

Molten Salt Small Modular Reactors

Molten Salt SMRs presents the SMRs that utilize molten salt fuelled (and cooled) advanced reactor technology.
  • Integral Molten Salt Reactor, Terrestrial Energy Inc., Canada

  • CMSR, (Seaborg Technologies, Denmark)

  • Copenhagen Atomics Waste Burner (Copenhagen Atomics, Denmark)

  • ThorCon (ThorCon International, Indonesia)

  • FUJI (International Thorium Molten-Salt Forum, Japan)

  • Stable Salt Reactor - Wasteburner (Moltex Energy, UK)

  • Stable Salt Reactor – Thermal Spectrum (Moltex Energy, UK)

  • Liquid Fluoride Thorium Reactor (Flibe Energy, USA)

  • Mk1 PB-FHR (UC Berkeley, USA)

  • Molten Chloride Salt Fast Reactor (Elysium Industries, USA and Canada)

Other Small Modular Reactors

(Other SMRs) presents the SMRs that cannot be classified into any of the above categories.
  • Westinghouse eVinci® Micro Reactor (Westinghouse Electric Company LLC, USA)


To find out much more, please read the full booklet that is downloadable from the IAEA website.

How Do SMRs Work?

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