Small nuclear reactors for a better future

An important point that emerged at the 2021 United Nations Climate Change Conference (COP-26) in Glasgow was that renewable energy resources such as solar, wind and hydropower cannot always be used to supplement energy generated by fossil fuels because they depend on weather conditions. .

The International Energy Agency (IEA) has noted that achieving net zero greenhouse gas emissions by 2050 will require doubling nuclear power worldwide. The most important reason for this is that nuclear power has an inherent flexibility to deal with fluctuations in energy demand and supply and to maintain grid stability. Besides generating electricity, nuclear power plants can also produce hydrogen and help decarbonize other sectors of the economy. As a result, nuclear energy is reappearing as an inevitable option for many countries.

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China, for example, plans to build around 150 reactors over the next 15 years at a cost of around $440 billion. India is exploring many options to reduce its carbon emissions. All thermal power plants in the country are expected to be closed by 2070. The government has announced a goal of tripling its annual nuclear power generation over the next 10 years.

NITI Aayog member and scientist VK Saraswat in a recent interview with PTI suggested that the government should focus on setting up small modular reactors as this would help meet India’s energy needs and could replace aging thermal power plants.

Simpler design, better utility

The International Atomic Energy Agency (IAEA) defines small nuclear reactors as those with an output of up to 300 MWe (MWe), or about one-third of the production capacity of traditional nuclear power plants. These reactors can be used for power generation, heat treatment, desalination or other industrial uses. SMRs primarily use low-enriched uranium as fuel and may use light water, gas, liquid metal, or molten salt as coolants. The modular design allows the control panel to have as many modules as needed. SMRs, given their low power and modularity, are best suited for both base load and flexible mode of operation and are therefore grid compatible.

Small reactors are simpler in design, sturdier than larger ones, and easier to build and operate. The most important feature is the inherent safety of the reactor. There is a paradigm shift in the level of safety in their design, with no large primary coolant pumping and piping systems used in large nuclear power plants.

SMRs use much lower amounts of fuel than conventional power plants. In the event of abnormal situations, the reactor will safely shut down and cool down without any operator intervention or external power source.

Large conventional nuclear power plants are mandated to prepare off-site emergency plans involving countermeasures such as sheltering, distribution of iodine tablets and evacuation of people in the vicinity in the event of an emergency. loss of coolant accident resulting in huge releases of radioactivity into the environment. SMRs, on the other hand, with their high passive safety characteristics, do not require any emergency countermeasures for the neighborhood.

Small reactors lend themselves to standardization, which reduces capital cost and minimizes the effort required to meet licensing requirements from regulatory agencies. As SMRs are less expensive and their construction and licensing times are shorter than for large reactors, the financial risk associated with a large investment is considerably reduced.

SMRs are designed so that they can be manufactured in an off-site factory, transported and assembled on site. The simplicity of design also means easier automation, maintenance, equipment inspection and operator training. As the space required for SMRs is greatly reduced, they can be easily installed in brownfields (previously developed land that is not currently in use) as a replacement for older coal-fired power plants. With all of these characteristics, SMRs can better support the economic, environmental and social basis for sustainable development.

Many SMR models

According to the International Atomic Energy Agency (IAEA), more than 70 SMR models are being studied in 17 countries. Several countries have already invested heavily in SMR technology. Recently, the United States Nuclear Regulatory Commission approved NuScale Power’s design for a 600 MW capacity plant consisting of 12 50 MW SMR modules. A few of them should be commissioned before 2030.

In Russia, a floating pressurized water reactor type power plant, named Akademik Lomonosov, with a production capacity of 77 MW, was commissioned in 2019. Rosatom of Russia is also building the SVBR-100 reactor, a generation reactor IV based on metallic refrigerant with a capacity of 100 MW. Recently, China ordered a high-temperature gas-cooled modular pebble-bed demonstration SMR (HTR-PM). Considered an industrial demonstrator, it has two reactor units driving a single 200 MW turbine.

In the UK, Rolls Royce is setting up a centralized manufacturing plant to produce SMRs. In Canada, Global First Power (GFP) has applied for a license to prepare a site for its 15 MW Micro Modular Thermal Reactor (MMR) at Chalk River in Ontario. In Poland, an electric utility, in collaboration with an American company, decided to install SMRs on its site after removing old coal-fired power plants, making efficient use of available resources such as grid connections, water supply, civil structures and skilled workers. .

A roadmap for India

The Department of Atomic Energy has decades of experience in the design, construction and operation of small research reactors and large nuclear power plants. It has also demonstrated its ability to build small compact reactors for nuclear submarines. Low-enriched uranium needed for SMRs can be imported under existing IAEA safeguards practices.

Like Poland, India can also consider installing SMRs on sites where coal-fired power plants are being dismantled. Scientists from the National Institute of Advanced Studies in Bengaluru have evaluated several of these candidate sites for the location of SMRs, as part of a research project.

The goal of reducing carbon emissions within the given timeframe can only be achieved if we can build SMRs involving the private and public sectors within a limited timeframe, if deemed necessary. To achieve this, the government should make appropriate changes to current electricity sector policies and regulatory review processes. These can ensure the radiation and environmental safety and physical security of nuclear facilities and will help ensure public acceptance of new reactors.

(The author is former Director (Radiation Safety), Atomic Energy Regulatory Board)

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