Small Modular Reactors

What is a Small Modular Reactor?

Small modular reactors (SMRs) are nuclear power plants and it is reported that they typically provide 300 MWe of electricity - enough to power 60,000 homes. They have been developed with particular innovation utilising a standardised and modular design to reduce costs in manufacturing and provide for shorter overall delivery times.

Small modular reactors are nuclear fission reactors that are generally smaller than regular reactors, which permits them to be fabricated at an off-site factory and brought to a site to be assembled. Their development brings opportunities to reduce costs due to not being linked to location development, offering increased production capacity and improved predictability of delivery. SMRs have been proposed as an approach to sidestep monetary and safety objections that have restrained the growth of the larger traditional nuclear reactors of late.

Key Takeaways
-  A Small Modular Reactor (SMR) is a category of nuclear power plant that utilises a standardised and modular design to reduce costs.
-  SMRs are being met with commercial anticipation due to opportunities to reduce costs and improved safety perceptions.
-  There are numerous SMR designs under development in countries accross the globe.

Small Modular Reactor

Are small modular reactors safe?

Small modular reactors, or SMRs, are setting a new level for safety in the industry. One example is that in the event of loss of off-site power, its remarkable design permits the reactor to cool itself without additional water, power or even administrator activity.

This is not to say that the existing and planned generation of larger nuclear power plants are unsafe. On the contrary, statistics will show you that they are the safest energy generation technology over the last decades.

What are the advantages that come with SMRs?

Small modular reactors offer a lower beginning capital speculation, more prominent versatility, and siting adaptability for areas incapable of obliging more conventional bigger reactors. They additionally have the potential for upgraded wellbeing and security contrasted with before plans. The organization of cutting edge SMRs can help drive monetary development.


The expression "modular" regarding SMRs alludes to the capacity to manufacture significant parts of the atomic steam supply framework in a processing plant climate and boat to the mark of utilisation. Even though current enormous thermal energy stations fuse processing plant-created parts (or modules) into their plans, a significant fieldwork measure is needed to gather segments into an operational force plant. SMRs are imagined to require restricted nearby planning and generously diminish the long development times ordinary of the bigger units. SMRs give effortlessness of configuration, improved wellbeing highlights, the financial matters and quality managed by processing plant creation, and greater adaptability (financing, siting, estimating, and end-use applications) contrasted with bigger thermal energy stations. Extra modules can be added gradually as interest for energy increments.

Lower Capital Investment

SMRs can decrease an atomic plant proprietor's capital speculation because of the lower plant capital expense. Measured parts and manufacturing plant creation can diminish development expenses and span.

Siting Flexibility

SMRs can give capacity to applications where huge plants are not required or destinations do not have the framework to help a huge unit. This would incorporate more modest electrical business sectors, segregated zones, more modest networks, locales with restricted water and land, or extraordinary modern applications. SMRs are relied upon to be appealing alternatives for the substitution or repowering of maturing/resigning fossil plants or to give a choice to supplementing existing mechanical cycles or force plants with a fuel source that doesn't transmit ozone harming substances.

Greater Efficiency

SMRs can be combined with other fuel sources, including renewables and fossil energy, to use assets and produce higher efficiencies and various energy finished results while expanding network solidness and security. Some high-level SMR plans can deliver a higher temperature measure heat for either power age or mechanical applications.

Safeguard & Security / Non-proliferation

SMR plans have the particular benefit of figuring in current shields and security necessities. Office security frameworks, including obstructions that can withstand plan premise aeroplane crash situations and other explicit dangers, are essential for the designing interaction being applied to the new SMR plan.

Economic Development

SMR sending to supplant resigning power age resources and meet developing producing needs would bring about critical development in homegrown assembling, charge base, lucrative processing plant, development working positions. A recent report on monetary and work effects of SMR organization assessed that a prototypical 100 MWe SMR costing $500 million to make and introduce would make almost 7,000 positions and create $1.3 billion in deals, $404 million in profit (finance), and $35 million in backhanded business charges. The report inspects these effects for various SMR arrangement rates, i.e., low (1-2 units/year), moderate (30 units/year), high (40 units/year), and troublesome (85 units/year). The investigation demonstrates huge financial effect would be acknowledged by building up an SMR fabricating venture at even moderate organization levels.

What about the disadvantages?

The undeniable downside is the expanded running expenses. Every kilowatt-hour (kWh) of power from an SMR would be relied upon to cost somewhere in the range of 15% and 70% above a kWh of power delivered in a full-sized thermal energy plant because of economies of scale. This implies power yield diminishes while different costs stay consistent. Likewise, the standard public feelings of trepidation encompassing atomic force age and atomic waste can make SMRs a hard sell, albeit a portion of the plans utilises a "raiser office", which assists with diminishing the waste yield. Configuration highlights, for example, this, joined with an expansion in information encompassing SMRs, should help turn away open feelings of dread over security.

Who are the designers of small module reactors?


In July 2019, China National Nuclear Corporation announced it would start building a demonstration ACP100 SMR by the end of the year at the existing Changjiang Nuclear Power Plant. The design of the ACP100 started in 2010. It is a fully integrated reactor module with an internal coolant system, with a 2-year refuelling interval, producing 385 MWt and about 125 MWe.


The ARC-100 is a 100 MWe 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, to complement existing CANDU facilities.

BWRX-300: United States

A scaled-down version of the ESBWR 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 an 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 a 235 U 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.

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 converting fertile isotopes into energy-producing fuel, efficiently using nuclear fuel, and closing the fuel cycle. Also, this can enable the reactor to be fueled 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 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 refuelled, with either 239Pu at 11% or 235U at 13%

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 (LFTR) technology (a type of molten salt reactor). The name "Flibe" comes from FLiBe, a Fluoride salt of Lithium and Beryllium used in LFTRs. Initially, a 20–50 MW (electric) version will be developed and followed by 100 MWe "utility-class reactors" later.

HTR-PM: China

The HTR-PM is a high-temperature gas-cooled (HTGR) pebble-bed generation IV reactor partly based on the earlier HTR-10 prototype reactor. The reactor unit has a thermal capacity of 250 MW, and two reactors are connected to a single steam turbine to generate 210 MW of electricity.

Hyperion Power Module (HPM): United States

A commercial version of a Los Alamos National Laboratory project, the HPM is an LMR that uses a Pb–Bi coolant. It has an output of 25 MWe and less than 20% 235 U enrichment. The reactor is a sealed vessel brought to the site intact and removed for refuelling 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 is a 33–291 MWe SMR design developed by Terrestrial Energy based in Mississauga, Canada. The reactor core includes components from two existing designs; the Denatured Molten Salt Reactor (DMSR) and Small Modular Advanced High-Temperature Reactor (smAHRT). Both designs are from Oak Ridge National Laboratory.

Main design features include neutron moderation from graphite (thermal spectrum) and fueled by low-enriched uranium dissolved in molten fluoride-based salt.

International Reactor Innovative & Secure (IRIS): United States

Developed by an international consortium led by Westinghouse and the nuclear energy research initiative (NERI), 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 a 5% enrichment of 235U that can run for five years between refuelling. Higher enrichment might lengthen the refuelling 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 the forced circulation of pressurized water during regular operation, although natural convection is usable in emergencies. The fuel may be enriched to above 20%, limiting low-enriched uranium, which may pose non-proliferation problems. The reactor has an active (requires action and electrical power) safety system with an emergency feedwater system. Refuelling is required every two to three years.

mPower: United States

The mPower from Babcock & Wilcox (B&W) is an integrated PWR SMR. The nuclear steam supply systems (NSSS) for the reactor arrive at the site already assembled and 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.

NuScale: United States

Originally a Department of Energy and Oregon State University project, the NuScale module reactors have been taken over by NuScale Power, Inc. The NuScale is a light water reactor (LWR), with 235U fuel enrichment of less than 5%. It has a 2-year refuelling period. The modules, however, are exceptionally heavy, each weighing approximately 500 tons. Each module has an electrical output of 60 MWe, and a single NuScale power plant can be scaled from one to 12 modules for a site output of 720 MWe.

Pebble Bed Modular Reactor (PBMR): South Africa

The PBMR is a modernized version of a design first proposed in the 1950s and deployed in the 1960s in Germany. It uses spherical fuel elements coated with graphite and silicon carbide filled with up to 10,000 TRISO particles containing uranium dioxide (UO2) and appropriate passivation and safety layers. The pebbles are then placed into a reactor core, comprising around 450,000 "pebbles". The core's output is 165 MWe. It runs at very high temperatures (900 °C) and uses helium, a noble gas, as the primary coolant; helium is used as it does not interact with structural or nuclear materials. Heat can be transferred to steam generators or gas turbines, which can use either Rankine (steam) or Brayton (gas turbine) cycles.

Purdue Novel Modular Reactor (NMR): United States

Based on the Economic Simplified Boiling Water Reactor designs by General Electric (GE), the NMR is a natural circulation SMR with an electric output of 50 MWe. The NMR has a much shorter Reactor Pressure Vessel compared to conventional BWRs. The coolant steam drives the turbines directly, eliminating the need for a steam generator. It uses natural circulation, so there are no coolant pumps. The reactor has both negative void and negative temperature coefficients. It uses a uranium oxide fuel with a 235U enrichment of 5%, which doesn’t need to be refuelled for 10 years.

Remote Site-Modular Helium Reactor (RS-MHR): United States

The RS-MHR is a General Atomics project. It is a helium gas-cooled reactor. The reactor is contained in one vessel, with all of the coolant and heat transfer equipment enclosed in a second vessel, attached to the reactor by a single coaxial line for coolant flow. The plant is a four-story, entirely above-ground building with a 10–25 MW electrical output. The helium coolant doesn’t interact with the structural metals or the reaction. It simply removes the heat, even at extremely high temperatures, which allow around 50% efficiency, whereas water-cooled and fossil fuel plants average 30–35%. The fuel is a uranium oxide coated particle fuel with 19.9% enrichment.

Rolls-Royce SMR

Rolls-Royce is setting up a nearby coupled three-circle PWR configuration, here and there called the UK SMR. The force yield is intended to be 440 MWe, which is over the typical reach viewed as an SMR. The plan focuses on a 500-day development time on 10 sections of land (4 ha) site. Generally speaking, form time is required to be four years, two years for site readiness and two years for development and appointing. The objective expense is £1.8 billion for the fifth unit constructed.

Toshiba 4S reactor design: Japan

Designed by the Central Research Institute of Electric Power Industry (CRIEPI), the 4S is an amazingly particular plan, created in an industrial facility and requiring next to no development on location. It is a sodium (Na) cooled reactor, utilizing a U–Zr or U–Pu–Zr fuel. The plan depends on a moveable neutron reflector to keep a consistent state power level somewhere in the range of 10 to 30 years—the fluid metal coolant permits electro-attractive (EM) siphons, with regular course utilized in crises.

Stable Salt Reactor (SSR): United Kingdom

The Steady salt reactor (SSR) is an atomic reactor configuration proposed by Moltex Energy. It addresses a leap forward in liquid salt reactor innovation, with the possibility to make the atomic force more secure, less expensive and cleaner. The plan's particular idea, including reactor centre and non-atomic structures, permits quick arrangement for a huge scope. The plan utilizes static fuel salt in regular fuel congregations, maintaining a strategic distance from many difficulties related to siphoning an exceptionally radioactive liquid and conforming to numerous prior global norms. Materials challenges are additionally incredibly decreased using standard atomic confirmed steel, with negligible danger of consumption.

Travelling Wave Reactor (TWR): United States

The TWR from Intellectual Ventures' TerraPower group is another creative reactor plan. It depends on the possibility of a parting chain response travelling through a centre in a "wave". The thought is that the sluggish reproduces and consumes the centre for 50 to 100 years without waiting to be halted, as a lot of fruitful 238U is provided. The just improved 235U required would be a slight layer to begin the chain response. Up until now, the reactor exists in principle. The lone testing finished with PC recreations. An enormous reactor idea has been planned, yet the little secluded plan is as yet being conceptualized.

Westinghouse SMR

The Westinghouse SMR configuration is a downsized variant of the AP1000 reactor, intended to produce 225 MWe.

How many homes can a small modular reactor power?

Most little particular reactors now underway reach between 50 megawatts – general power for 60,000 modern homes – and 200 megawatts. There are more plans for much more modest "small scale" or "miniature reactors" that produce as not much as 4 megawatts.

*BEIS states that the average electricity usage per household in the UK is 3,731kWh/year. A 300MWe SMR will provide 300,000kWh, therefore, powering 80 house per year.

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