Some notable types of SMR reactors
Small Modular Reactors (SMRs) are an emerging technology that has become an option in some countries' future energy strategies.
In this article, "What are Small Modular Reactors?" you can learn what an SMR is, their advantages and disadvantages, the reasons why they are considered a future option, and other applications for these reactors beyond electricity production.
All SMRs have common characteristics in terms of simplicity of design, cost savings, ease of manufacturing and construction, modularity, etc. However, there are several aspects that make them different, which is why it can be said that there are more than 50 known small modular reactor designs in various stages of development, from conceptual design to construction.
The following image shows most of the countries involved in projects of this type and some of the most notable ones:
Below are some of SMR's most notable projects:
AHWR (India)
Its full name is "Advanced Heavy Water Reactor" and it was designed by the Bhabha Atomic Research Centre.
It is a light water-cooled, heavy water-moderated HWR reactor with a thermal output of 920 MWt (300 MWe gross).
It has a design life of 100 years and 90% availability.
It uses 452 MOX fuel elements, but the design and developments currently underway aim to achieve large-scale use of thorium for commercial power generation. It has passive safety systems and a closed fuel cycle has been considered to reduce its environmental impact.
Its applications include electricity generation and water desalination (approximately 2,400 m3/day).
For more information: AHWR Project - Bhabha Atomic Research Centre
ALFRED (Italy)
Its full name is "Advanced Lead Fast Reactor European Demonstrator," and it was designed by the Italian company Ansaldo Nucleare within the framework of the European Union's FP7 LEADER (Lead-cooled European Advanced Demonstration Reactor) project.
It is a pool-type, lead-cooled fast reactor with a thermal output of 300 MW (125 MWe). It uses MOX fuel with a fuel cycle of 1 to 5 years and has a design life of 40 years.
The purpose of its development is to demonstrate the viability of European LFR (ELFR) technology for use in future commercial nuclear power plants, as it is the most plausible option for short-term construction.
It is in the early design phases, and the first reactor is expected to be ready for commercialization in 2025.
For more information: ANSALDO ENERGIA
ALLEGRO (European Union)
It is a 75 MWt experimental helium-cooled fast reactor being developed by the V4G4 Centre of Excellence Association, a group of nuclear research organizations from the Czech Republic, Hungary, Poland, and France.
This project is an important step in the development of GFR (Gas-cooled Fast Reactor) reactors, as it is one of six GFR reactor concepts selected by the Generation IV International Forum as a plausible future option and one of three fast reactors supported by the European Sustainable Nuclear Energy Technology Platform.
ALLEGRO's main focus is the development of GFR fuels (carbide fuels), helium-related technologies (components, instrumentation, purification, etc.), safety systems, and corresponding safety regulations (requirements, criteria, guidelines). However, it also tests the use of high-temperature reactor coolant to generate heat for use in industrial processes and research facilities.
For more information: ALLEGRO Project
CAREM-25 (Argentina)
It is a reactor entirely designed and built in Argentina by the National Atomic Energy Commission (CNEA). Located in Lima, Buenos Aires, it is a variant of the PWR reactor (this type of reactor accounts for almost three-quarters of the reactors in operation worldwide).
With a design life of 40 years, it is intended to produce electricity at low and medium power levels. It was initially designed to generate 25 MWe of power, but, following successive engineering improvements, it will be capable of generating 32 MWe, which will supply a population of approximately 120,000.
Civil engineering work began on February 8, 2014, leading the International Atomic Energy Agency (IAEA) to officially declare it the world's first SMR under construction.
In parallel with the development of this prototype, the National Atomic Energy Commission (CNEA) is advancing the conceptual design of what will be the commercial module for CAREM. This module will have a higher capacity (100 to 120 MWe) and will be the basis of a multi-reactor plant that will allow for highly competitive costs in the international market.
For more information: CAREM – NATIONAL ATOMIC ENERGY COMMISSION
CMSR (Denmark)
Its full name is "Compact Molten Salt Reactor" and it was designed by the Danish company Seaborg Technologies. It has a thermal capacity of 250 MWt (100 MWe).
This reactor differentiates itself from conventional reactors by its ability to operate with conventional molten salt fuel as well as a combination of spent nuclear fuel and thorium. Every 10 years, the fuel and coolant are removed for replacement and taken to the factory for recycling.
Furthermore, the reactor's outlet temperature is high enough to efficiently produce hydrogen, synthetic fuel, and fertilizers.
It has a design life of 60 years and will be able to produce electricity, provide clean water, and heat/cooling to approximately 200,000 homes.
This reactor is in an early design phase. A final design, pre-prototype, and licensing are expected by 2020, with a full-scale prototype by 2025 and commercial operation by 2027.
For more information: SEABORG
FBNR (Brazil)
Its full name is "Fixed Bed Nuclear Reactor," and it is a pressurized water reactor (PWR), cooled and moderated by water, with a capacity of 218 MWt (72 MWe).
Designed by the Federal University of Rio Grande do Sul (FURGS), it is still in the very early stages of development.
This spherical reactor does not require on-site refueling; instead, the fuel chamber is removed (without opening the reactor) and replaced with fresh fuel.
The spent fuel is confined in the fuel chamber and kept in a water tank for cooling. It can be sent to the plant at any time as long as radiological requirements are met. Furthermore, due to the fuel's shape, it can have useful applications in industry, agriculture, and medicine as a radiation source.
It is designed to produce electricity alone or in conjunction with cogeneration plants, for seawater desalination or steam generation for industrial purposes, and to supply district heating.
For more information: FBNR Project
FUJI (Japan)
Its name comes from Mount Fuji, a very important element in Japanese culture, and it was designed by the International Thorium Molten-Salt Forum (ITMSF).
It is a molten salt reactor that uses molten fluoride as a coolant and graphite as a moderator. It has a thermal output of 450 MWt (200 MWe) and its fuel is a molten salt composed of thorium and uranium.
It has a design life of 30 years and is characterized by high safety, high economic performance, its contribution to non-proliferation, and a flexible fuel cycle.
It can be used to produce electricity, but also to transmute plutonium and/or minor actinides, desalinate seawater, or produce hydrogen.
For more information: FUJI
HTMR-100 (South Africa)
Its full name is "High Temperature Modular Reactor," and the "100" refers to its thermal output (35 MWe). Designed by Steenkampskraal Thorium Limited (STL), it is a high-temperature, gas-cooled, graphite-moderated ball-bed reactor.
With a design life of 40 years, the fuel consists of 150,000 spheres that can be recharged without shutting down the reactor.
Its applications include electricity generation, cogeneration, and industrial processes (oil refining, oil recovery, natural gas and coal plants, petrochemicals, hydrogen production, fertilizer production, etc.).
The conceptual design phase was completed in 2019.
For more information: HTMR-100 Reactor
HTR-PM (China)
Its full name is "High Temperature Gas Cooled Reactor – Pebble-Bed Modular" and it was designed by INET Tsinghua University.
It is a high-temperature pebble-bed reactor cooled and moderated by helium/graphite, and each module has a thermal output of 250 MWt (105 MWe). A typical power plant with this reactor typically has two modules connected to a single turbine.
One of its advantages is that it uses uranium spheres coated with graphite and ceramic as fuel, which are capable of withstanding very high temperatures and thus controlling nuclear reactions. Each reactor module contains 420,000 spheres that are recharged online, without shutting down the reactor, during its 40-year design life.
Work on the first HTR-PM demonstration plant began in December 2012 at the Shidao Bay Nuclear Power Plant. The vessels for both reactors were installed in 2016, and the plant is expected to begin generating electricity in 2020, becoming the first Generation IV reactor to enter operation.
For more information: HTR-PM Project
IMSR-400 (Canada)
Its full name is "Integral Molten Salt Reactor," and it was designed by Terrestrial Energy with a thermal capacity of 400 MWt (194 MWe). It is a conventional solid-fuel reactor that uses fluorinated salts as a coolant and graphite as a moderator.
This reactor's unique feature lies in its location of the moderator, as it is an independent and replaceable unit that can be located in the vessel or directly attached to it. It also includes pumps and their motors, control rods, and heat exchangers.
Furthermore, it uses an online fuel supply system, so for seven years it is not necessary to open the vessel to extract fuel from the reactor. This makes it safer, generates fewer refueling outages, and allows for longer reactor operating times than conventional reactors.
In October 2018, this design passed the second phase of certification by the Canadian Nuclear Safety Commission, so the design company expects to have its first IMSRs on the market in the 2020s.
It is designed for a 60-year operating life and is expected to produce not only electricity but also other applications such as district heating; hydrogen, liquid fuel, or ammonia production, industrial cogeneration; mineral resource extraction; and petrochemical refineries.
For more information: Terrestrialenergy
IRIS (International consortium)
It stands for "International Reactor Innovative and Secure," and is a project coordinated by Westinghouse (United States) with the participation of companies, laboratories, and universities from around the world, especially Brazil, Croatia, Spain, the United States, Italy, Japan, Lithuania, Mexico, the United Kingdom, and Russia. It is a smaller-scale Integral PWR reactor. Integral means that the steam generators, pressurizer, control rod drive mechanisms, and reactor coolant pumps are located inside the vessel, making it slightly larger than would be the case for a power plant of this size.
It is a water-cooled and moderated reactor with an unspecified power output. A first approximation has been proposed for a thermal output of 1,000 MWt (335 MWe gross), but it could be adjusted to as low as a 100 MWe unit. With a design life of 60 years, it uses 89 uranium oxide (UO2) and MOX fuel elements that operate for a maximum of 48 months. It is currently in a basic design phase, with comprehensive large-scale testing activities being carried out, especially by Italian organizations (ENEA, SIET, CIRTEN). The primary application of this reactor is electricity generation. However, it can support heat production and seawater desalination. It is also possible to operate in conjunction with renewable energy parks and energy storage systems.
KTL-405 (Rusia)
It is a PWR reactor with a capacity of 150 MWt (35 MWe) designed by JSC Afrikantov OKB Mechanical Engineering (OKBM). The reactor technology is based on another already commercialized reactor, the KLT-40, which is used for marine propulsion and is an advanced variant of the RP reactor used in Russian icebreakers.
Two reactors of this type will be used in Russian floating nuclear power plants, specifically designed to supply electricity to remote areas of Siberia isolated from the Russian main grid. They are currently being used to power the Sevmorput freighter and the Takhmyr and Vaygach icebreakers. They will be factory-built and then towed to their final locations.
With a design life of 60 years, each reactor has 121 fuel assemblies and refueling periods are every two to three years. Because of its remote location, the spent fuel is expected to remain on board for up to 12 years before being transferred to a specialized storage facility or for reprocessing.
Russia's first floating nuclear power plant is the Akademic Lomonosov, and after nearly a decade of construction, it reached its final destination, a remote area in northern Russia, on September 14, 2019, with the goal of supplying enough electricity for approximately 100,000 homes.
For more information: OKBM
LFR-AS-200 (Luxemburg)
Designed by the Luxembourg-based company Hydromine Nuclear Energy, this is a liquid metal-cooled, pool-type fast reactor with a capacity of 480 MWt (200 MWe). LFR stands for "Lead Fast Reactor," AS refers to the amphora-shaped inner vessel, and 200 refers to the electrical output in MW.
It operates on a hexagonal MOX fuel consisting of 61 fuel elements arranged in five bundles that produce electricity for 80 months. It has a design life of 60 years and is in the preliminary design phase.
Its applications include electricity generation and spent fuel reprocessing, reducing the volume and quantity of minor actinides in radioactive waste.
For more information: HYDROMINEINC
NuScale (The United States of America)
Its full name is “NuScale Power Modular and Scalable Reactor,” and it was designed by NuScale Power Inc. It is one of the best-known designs and has recently received authorization from the United States Nuclear Regulatory Commission (NRC) to begin construction.
The approved project is for a plant with 12 modules to be built in Idaho (United States), each with a thermal capacity of 200 MWt (60 MWe gross). Therefore, rather than a single SMR reactor, the project itself represents 12 SMR reactors.
Each module will be fueled with standard light water reactor fuel in a 17x17 configuration, and each fuel element will measure 2 meters, sufficient to operate for two years.
It has a design life of 60 years. The first nuclear power plant of this type will begin construction in the mid-2020s and is expected to be operational in less than 10 years.
For more information: NuScale Project
SEALER (Sweden)
Its full name is "Swedish Advanced Lead Reactor," and it is a design by the Swedish company Leadcold. It is a passively lead-cooled reactor, and the integrity of the exposed steel surfaces is ensured by the use of alumina-based alloys containing 3-6% aluminum.
It has a design life of 30 years, and fuel does not need to be replaced during this time, minimizing management costs.
Several models are depending on the intended application of the reactor. If the primary objective is to produce electricity, there are two models of this reactor, depending on the area where it will be installed:
- In the Arctic (remote area). The goal is to produce electricity with a capacity of 3 to 10 MWe, and this requires 2.4 tons of 19.9% enriched UO2 as fuel. It has a design life of between 10 and 30 years (depending on the capacity) and 9% availability.
- In the United Kingdom (with an already configured grid), it would also be used to produce electricity with a nominal capacity of 55 MWe, which would require 19.8 tons of 11.8% enriched uranium nitride. It has a design life of 25 years and 90% availability.
Five years after the end of SEALER's operational life, the entire reactor will be transported to a centralized waste management facility.
For more information: LEADCOLD
SMART (South Korea)
Its full name is “System-Integrated Modular Advanced ReacTor,” and it was designed by the Korea Atomic Energy Research Institute (KAERI). It is an integral, water-cooled and moderated reactor with a thermal output of 330 MWt (100 MWe).
Integral means that the steam generators, pressurizer, control rod drive mechanisms, and reactor coolant pumps are located within the vessel.
With a design life of 60 years, it uses 57 uranium oxide (UO2) fuel elements in a 36-month cycle.
Its applications, in addition to electricity production, also include seawater desalination, district heating, and industrial process heat production. It is a good choice for regions with small or isolated grids. For example, one unit can meet the electricity and water needs of a population of 100,000.
It is currently certified (licensed), meaning the standard design has been approved by the Korean regulatory body.
For more information: SMART POWER CO., LTD
UK-SMR (United Kingdom)
This reactor, designed by Rolls-Royce, is a three-loop pressurized water reactor (PWR). It has a power output of 1,200-1,300 MWt (400-450 MWe) and uses uranium oxide as fuel.
It has a design life of 60 years, and the primary purpose of this reactor is electricity production. However, its design, which is still in its development phase, can be configured to support other applications such as heat production or cogeneration.
Design Acceptance Confirmation (DAC) and Statement of Design Acceptability (SoDA) are expected to be achieved in 2023, so the first reactor of this type could be operational by 2030.
To learn more about the UK SMR manufacturing process: UK-SMR Fabrication
For information on SMR's UK reactor programme, see: UK SMALL MODULAR REACTORS and for more information:
