By Girish Linganna
The expansion of civilian nuclear cooperation between India and Russia was decided upon during External Affairs Minister S Jaishankar’s visit to Moscow in December 2023. Moscow is prepared to offer India its technological knowhow to develop a compact modular reactor that can generate power in capacities ranging from 75 MW to 300 MW.
But what are small modular reactors (SMRs) and how are they superior to traditional nuclear power plants? For over a decade now, discussions worldwide have been centered on SMRs, also called mini-Nuclear Power Plants (mini-NPPs). These reactors are considered to be the nuclear power stations of the future. There is nothing new about these stations in—and of—themselves. When it comes to technology, they are comparable to pressurized water reactors, often known as PWRs.
Power units of fewer than 300 MW are considered ‘small’ by the International Atomic Energy Agency (IAEA), whereas power units with up to 700 MW are considered ‘medium’. The International Atomic Energy Agency (IAEA) collectively refers to them as Small Medium Reactors (SMR). On the other hand, the abbreviation SMR is frequently used to refer to ‘small modular reactors’, which is intended for building in a serial fashion. In addition, there is a sub-class of very small reactors, which are known as ASMRs—installations that have a power capacity of less than 15 MW and are designed for use in extremely isolated places.
The technology behind low-power nuclear power plants is not a new development. The power of reactor units has increased from 60 MW to more than 1,600 MW since the beginning of nuclear energy. Currently, there is an approach for the development of small nuclear plants. This is partly due to the high capital expenditures of constructing large power reactors that generate energy through the steam cycle, and partly due to the requirement to service small power grids. The capacity of these installations can be increased as required through modular construction, which uses small reactor blocks.
These installations can be built independently, or as modules inside a larger complex. When it comes to modularity, the savings predicted are projected to come from scalability. Besides, additional smaller-scale reactor installations are being developed for use in isolated places. This type of installation requires relatively minor investments compared to the cost of constructing massive reactors, which is comparable to the capitalization of the utilities interested in acquiring them.
More than 90% of these coal-fired power plants have a capacity of less than 500 MW and some even have a capacity of less than 50 MW. This is another reason why small modular reactors (SMRs) are becoming increasingly popular.
SMRs operate on the same fundamental concept as standard nuclear reactors, generating heat through nuclear fission. This heat is converted into steam, which drives turbines and generates energy. Atoms of uranium fuel are divided into fission, producing energy. SMRs are intended to be both more efficient and safer. Many employ passive safety systems that rely on natural forces—such as gravity, convection and heat resistance to reduce the danger of accidents. Their smaller size enables faster and more flexible deployment and they may be quickly turned off when not in use. SMRs are being developed to work with renewable energy sources to provide consistent, low-carbon power supply.
To fulfil its obligations under the terms of the Paris Agreement, the Indian government has created a roadmap for a switch to carbon-free energy. India intends to implement this approach to shift its energy industry to entirely carbon-free by 2070.
In this strategy, nuclear energy is given special consideration. India now has seven nuclear power facilities with 22 operational nuclear reactors, while seven more generating units (not including reactors being developed at research centres) are under construction. India is second to China in the world in terms of the total number of nuclear power units being built concurrently.
Speaking at a conference on SMRs organized by the government think-tank, NITI Aayog, in November 2023, Minister of State Jitendra Singh discussed the need to rely on building modular reactors with a maximum capacity of 300 MW. According to Singh, the primary distinction between these reactors and high-power reactors which are built on-site, is that the reactor for these units is built entirely at the plant and transported to its intended operating location, substantially simplifying construction logistics.
Small reactors have several advantages over large reactors, including their design flexibility and requirement for less space, as well as significant cost savings and shorter construction times, while maintaining a high degree of safety, according to the minister. He underscored two concerns while emphasizing the necessity for a thorough investigation into creating tiny modular reactors: first, exchanging technologies with businesses that have developed low-power reactors; and, second, resolving the issue of sufficient funding.
Russia has made significant advancements in the design of SMRs. A 50-MW NPP based on the RITM-200 reactor is one of the most intriguing concepts. An SMR of this type is predicted to operate for 60 years using a six-year fuel cycle. Afrikantov OKBM, the developer, intends to construct the first station by 2027. The Suroyamskoye iron ore deposit area in the Chelyabinsk region and the Peschanka gold-copper deposit territory in Chukotka are the two most promising building locations being considered. The station is a component of the national project, ‘Nuclear Science: Technology and Technologies’, which was started by Rosatom.
There are also smaller nuclear reactors with capacities ranging from 6 MW to 10 MW. These reactors, particularly the ‘Shelf’ and ABV-6E versions, are intended for use in distant and difficult places. OKBM is in charge of ABV-6E development, whereas NIKIET controls the ‘Shelf’ reactor.
NIKIET is also working on several projects using tiny power units. A transportable modular nuclear power station with a 1.2-MW gas-cooled ATGOR reactor is among the well-developed ones. This reactor has a 60-year operating life and requires nuclear fuel refilling every 10 years. It is worth noting that the reactor can be started at temperatures as low as -50°C.
Furthermore, the power plant can be launched using gas turbines, removing the requirement for external power sources. On the unit, parallel gas turbine installations can generate energy. This tiny NPP’s core equipment, weighing 60 tons, may be accommodated on two-wheeled platforms readily carried by conventional semi-trucks.
Furthermore, Rosatom operates the world’s only operational floating nuclear thermal power plant (FNPP) based on the Akademik Lomonosov floating power unit containing two KLT-40S reactors. Reactor installations of the KLT-40 type used as part of floating nuclear power plants have proven themselves in the Russian nuclear icebreaker fleet during many years of accident-free operation. The station’s electrical capacity is 70 MW. (IPA)
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