The International Atomic Energy Agency (IAEA) has, last month, published a report on small modular reactors (SMRs) as a guide that can help countries identify suitable nuclear reactor designs in their search for reliable and affordable energy sources towards cutting down carbon emissions, and for meeting the goals agreed upon at the UN’s 2015 Paris Conference of Parties (CoP 21) on tackling the urgent issue of climate change.
The IAEA report titled Advances in Small Modular Reactor Technology Developments provides the latest data and information on SMRs around the world, including detailed descriptions of 72 reactors under development or construction in 18 countries. Expanding on an earlier IAEA report on SMRs, this booklet provides annexes on waste management and disposal, as well as a section on very small SMRs called microreactors.
Launching the latest report at a webinar, the head of the IAEA’s Nuclear Power Technology Development Section, Stefano Monti, said: “SMRs’ unique attributes in terms of efficiency, flexibility and economics may position them to play a key role in the clean energy transition. Countries can use the updated booklet as an additional tool for identifying possible technological solutions to the challenges they face on energy, climate change and sustainable development.”
Unlike large power reactors with capacities in the range of 700-1,000 MW, SMRs typically have a capacity of up to 300 MW and are built largely from prefabricated components assembled on site. They are designed for less upfront capital and have wider financing schemes. Their modular nature also allows for scaling up capacity by adding units according to demand. According to the IAEA, SMRs are also better suited to operate flexibly in tandem with variable renewable energy sources such as wind and solar, as well as for non-electric applications such as seawater desalination, district heating and hydrogen production.
Almost all Asian countries that have embarked on civilian nuclear energy programmes have been guided by the major concern of providing energy security for their populations, reduce dependence on fossil fuels in the context of climate change, as well as the cost of nuclear technology, which has become an important factor as prices have risen sharply in the last decades. What adds to the cost of conventional nuclear power plants (NPPs) in the 700-1000 MW category are long construction periods and related delays, parting from the initial requirement of large land areas for setting up such NPPs.
In such a context, SMRs provide an attractive proposition, foremost from the cost aspect, while addressing other related concerns of safety, the issue of nuclear waste and that of the large land requirement for NPPs. Moreover, SMRs can also help address the electricity requirements of far flung communities that are dispersed over the hinterlands of rural Asia.
For small and modular reactors to become successful in the Asian situation, these must satisfy the major requirement of safety, as well as cost-efficiency in both construction and operation, as compared to NPPs. SMR construction can be carried out by small utilities and are much easier to operate and maintain in remote areas.
According to extant research in this field, SMRs provide increased safety by providing among others, more efficient passive heat removal from the reactor vessel and greater quality control. These also have much lower land requirements, lesser delays in construction and involves significantly smaller displacement and rehabilitation of population displaced through land acquisition that would otherwise be necessary for conventional NPPs.
The most compelling argument for the suitability of SMRs for Asian nations is from the financial point of view of lower capital requirement and the attendent potential of permitting tighter control over the three key related aspects of operation, maintenance and safety.
Taking the specific case of India, which boasts of one of the bigger civilian nuclear energy programmes in Asia, and which has significant reserves of thorium, the small thorium cycle-based high temperature gas cooled reactors (STGRs) of 20-40 MW sizes allow the possibility of major cost and time saving by eliminating the chances of nuclear accidents.
While wider deployment of SMRs is expected to begin over the next decade, two reactor units of KLT-40S design are already in operation in Russia aboard the world’s first floating NPP Akademik Lomonosov built by the Russian state atomic energy corporation Rosatom. The Akademik Lomonosov became the world’s first SMR power plant to enter commercial operation when it was connected to the grid in Russia’s remote Chukotka region in December 2019. It’s also the world’s northernmost NPP, providing both heat and electricity to the sparsely populated area and facilitating the shutdown of the coal-fired Chaunsk power plant.
Russia is also developing a land based SMR project planned for commissioning in 2027, according to Elena Pashina, Marketing Director for Rusatom Overseas. “SMR NPPs can provide electricity to remote areas and areas with grid restrictions at a favourable price as compared with alternatives and also satisfy growing energy needs,” she said at the webinar.
Two other countries which have made significant advances in SMR technology — Argentina and China — are due to begin their operations within the next three years. Argentina, China and Russia presented their progress on SMR technology in the webinar.
Argentina is developing the 25 MW CAREM SMR, which is intended for small electric grids and may also support seawater desalination, with construction of the prototype nearing completion. “The CAREM25 prototype is the first step in the development of a competitive SMR, and it will facilitate licensing activities for the commercial modules and local supplier development. CAREM will allow for nuclear power deployments in remote areas and small grids, providing a stable supply of electricity while reducing carbon emissions,” said Dario Delmastro, Engineering Manager of the CAREM Project at the National Nuclear Energy Agency of Argentina.
China’s HTR-PM, a prototype high temperature gas cooled SMR located in Shidao Bay, is expected to begin operations next year. The reactor is cooled by helium and capable of reaching temperatures as high as 750 degrees Celsius, making it suitable for non-electric applications such as district heating and hydrogen production. The HTR-PM is also designed with inherent safety features that reduce the risk of radioactive releases.
The IAEA’s latest report has six parts, focusing on land-based water cooled SMRs, marine-based water cooled SMRs, high temperature gas cooled reactors, small fast neutron reactors, molten salt SMRs, and micro modular reactors, with capacity of less than 10 MW.
The booklet part on fast neutron spectrum SMRs presents several designs with different coolant options, including sodium, heavy liquid metal and helium gas. The BREST-OD-300, a lead-cooled fast neutron reactor, is currently under construction at Seversk in Russia with a scheduled operation by end of 2026. This is a demo-prototype project for future design with large power to enable a closed nuclear fuel cycle.