SMRs: Key Players in the Energy Transition Toward Decarbonization

SMRs: Key Players in the Energy Transition Toward Decarbonization

Nuclear power, as a low-carbon source of electricity, plays an important role in decarbonizing the power sector. Small modular reactors (SMRs) provide opportunities for nuclear power to be used in power generation. SMRs are being considered for grid flexibility in addition to baseload power due to their modular nature, low cost, and land requirements.

A recent NITI Aayog report titled “The Role of SMRs in Energy Transition” emphasizes the role of SMRs in facilitating the energy transition. It also discusses the advantages and disadvantages of SMRs, as well as a potential roadmap for their deployment. The report’s key takeaways are presented by Power Line…

SMR characteristics and benefits

SMRs are advanced nuclear reactors with power generation capacities ranging from less than 30 MWe to 300+ MWe, according to the International Atomic Energy Agency (IAEA). These reactors are much smaller than conventional nuclear power reactors. They have modular systems and components that make them simple to install, transport, and assemble.

They use nuclear fission to generate heat for power generation or direct application. Cogeneration SMR systems not only meet the needs for electricity and process heat, but they also have the potential to supplement variable renewables through flexible operations. They can also be installed in remote off-grid locations. As a result, they can play a critical role in achieving the energy transition goals.

SMRs have several advantages. They are intended to have their systems, structures, and components (SSCs) manufactured in a controlled factory environment and then transported to the project site for installation, reducing project time and costs. They offer deployment benefits such as a smaller emergency planning zone and the use of passive safety systems. SMRs could also be used to repurpose decommissioned fossil-fuel-fired power plants. SMR designs require refueling every three to seven years, whereas some models can operate without refueling for up to 30 years during their expected operating lifespan. They can increase the capacity of a power plant later on by adding more modules. 

The capital investment per reactor is low, and the capital investment per MW, while higher than for larger reactors (LRs), can be reduced as more units are built.

Global development and deployment of SMR technology

Governments, regulators, industry groups, academic institutions, and companies have all taken steps to advance SMR technology. Several SMR designs have received preliminary regulatory approvals and are being considered for construction, operation, and grid coupling.

Globally, two SMR projects have reached the operational stage. These include the Akademik Lomo­nosov floating power unit in the Russian Federation, which consists of two 35 MW(e) KLT-40S modules and was grid-connected in December 2019; and the HTR-PM demonstration SMR in China, which achieved grid connection in December 2021 and is aiming for a full 210 MW(e) power operation in 2023.

On a global scale, approximately 80 SMR designs are currently in various stages of development, licensing, deployment, and operation. Some popular SMR designs include:

1). Land-based water-cooled SMRs: Water-cooled SMR designs with various configurations of light water reactor and pressurized heavy water reactor (PHWR) technologies such as integral pressurized water reactors (PWRs) and PHWR, compact PWR, loop-type PWR, boiling water reactors, and pool type PWR for on-land applications are included in this category. These designs are based on mature technology that is used in the majority of operational LRs.

2). Water-cooled SMRs for marine deployment: These SMRs include water-cooled SMR designs for marine deployment. They can be constructed on floating units mounted on barges or ships.

3). High-temperature gas-cooled SMRs (HTGRs): HTGRs produce very high-temperature heat that exceeds 750 degrees Celsius, resulting in increased electricity generation efficiency. 

They are simple to integrate into a variety of industrial applications and are ideal for cogeneration.

4). Liquid metal-cooled fast neutron spectrum SMRs: SMRs in this category use liquid metal coolants such as sodium, lead, and lead-bismuth and are based on fast neutron technology.

5). Molten salt reactor SMRs (MSRs): These SMRs use molten fluoride or chloride salt as a coolant. MSR designs for both the thermal neutron and fast neutron spectrums are being developed. These technologies can sustain long fuel cycles that last several years and can be re-fueled online where fresh fuel can be introduced in molten form. This method allows for the online cleaning of fission products.

6). Microreactors (MRs): MRs are small SMRs that can generate up to 10 MW of power (e). Coolants such as light water, helium, molten salt, and liquid metal are used.

Bringing the licensing process and regulatory requirements in line

Harmonization of the licensing process and regulatory requirements, according to the NITI Aayog report, will be a critical step in expediting the development of SMR designs, reducing construction and installation time, and optimizing costs. Enabling policy and regulatory frameworks, as well as legal aid and safety provisions, are required for large-scale SMR manufacturing. Through initiatives such as the Nuclear Harmo­nization and Standardization Initiative, the SMR Regulators’ Forum, and the Coor­di­nated Research Projects, the International Atomic Energy Agency (IAEA) has played a critical role as an enabler in establishing these frameworks.

Industry difficulties

The report focuses on the various challenges that the SMR industry faces. It observes that the concurrent development and adoption of a large number of SMR technologies would pose regulatory challenges to the nuclear industry and reduce cost optimization. To maintain economies of scale, the options must be narrowed down to a few SMR designs. Another challenge is the requirement to improve the Technology Rea­di­ness Levels of available SMR designs for them to be considered for deployment by utilities, investors, and governments. Aside from that, the report mentions that the SMR industry has yet to fully develop an operational fabrication facility for large-scale serial component manufacturing. Establishing such a facility would necessitate a sizable investment. This presents a problem for technology developers who must secure funding for technology development, licensing, and the construction of prototype plants. This problem is exacerbated by a lack of private capital.

The Future of SMR Deployment

According to the report, the focus on SMRs is motivated by the goal of developing a standardized, small-sized reactor that can be manufactured repeatedly in a quality-controlled environment and in a standardized manner. Furthermore, as the industry grows, the learning curve value and serial production economies can take effect, lowering production costs. The SMR industry is currently in its early stages, with ongoing technological evolution, prototyping of SMR modules, cost optimization, and regulatory clearances. The industry must overcome obstacles such as technology demonstration, material availability, manufacturing techniques, project funding requirements, and regulatory harmonization.

According to the report, a healthy SMR ecosystem is dependent on the standardization of component designs and modules. The current safety assessment methodology must be updated to account for new technology such as multi-module designs and SMR emergency planning zones. According to the report, the availability of finance at lower rates of return, inclusion in the green taxonomy, and the use of innovative financing instruments such as blended finance and green bonds can all encourage private investment in the sector. Furthermore, personnel upskilling across the value chain is required, including engineering, design, testing, inspection, construction, erection, and commissioning for multi-module plants.

The report emphasizes the importance of forming strategic partnerships that foster collaboration among national laboratories and research institutions, academic institutions, private companies, and government departments to achieve optimal technological and economic outcomes. It also adds that these collaborative efforts at the IAEA level should be expanded to coordinate with countries in developing an ecosystem that can yield greater benefits.


SMRs are emerging as a dependable solution for supplying clean and reliable power as well as mitigating the intermittent nature of renewable energy. To ensure the successful development and deployment of SMRs, it is critical to address the challenges associated with a lack of a policy and regulatory roadmap, a shortage of skilled manpower, standardization, and the availability of financing.