[Reading Science] Next-Generation Small Modular Reactors: Securing Core Technologies Is Key

According to the concept, environmental, economic, and safety issues can all be resolved
Decarbonization alternatives and energy security highlighted as key measures
Major countries focus on SMR research, aiming for commercialization in the 2030s
"Korea also needs an all-out effort including enacting support laws"

Sodium-cooled Fast Reactor (SFR) under development by the Korea Atomic Energy Research Institute. Photo by Korea Atomic Energy Research Institute

[Asia Economy Reporter Kim Bong-su] Next-generation Small Modular Reactors (SMRs) are rapidly emerging as future energy sources that capture the three key benefits of safety, economic efficiency, and environmental friendliness. Countries around the world are engaged in an all-out effort to develop next-generation reactors such as SMRs as a means to ensure energy security and achieve carbon neutrality in response to climate change. Experts have pointed out the need for efforts to secure fundamental technologies through international cooperation, enactment of support laws, and the establishment of control towers, as these are strategic technologies that must be secured.

Why SMR?

Recently, as the international community has been pushing for carbon neutrality by 2050 to respond to climate change, the role of nuclear power as an essential energy source for decarbonization has been re-evaluated. The International Energy Agency (IEA) notably identified nuclear power as a necessary means at the point of energy transition. The European Union (EU) also included nuclear power conditionally in its green taxonomy, which classifies eco-friendly energy sources based on carbon emissions per energy source, with conditions such as securing waste disposal facilities. Following the outbreak of the Russia-Ukraine war earlier this year, which has caused global energy supply instability, countries worldwide are actively pursuing independent supply chains to strengthen energy security, with SMRs being promoted as an alternative.

Unlike conventional large nuclear power plants, SMRs aim to minimize piping and equipment and achieve mass production and assembly through standardization. Research is underway to address issues such as waste disposal costs, safety, and output control by recycling spent fuel rods (pyroprocessing) and using sodium or molten salt coolants. SMRs have a high potential to solve the problems of existing large nuclear plants and improve economic efficiency. Economic viability can be secured through manufacturing, production, and operational know-how accumulated over decades of nuclear plant operation, modularization, process innovation, mass production, and cost reduction. Furthermore, with the advancement of cutting-edge information and communication technology (ICT), innovations in overall nuclear plant operation and management are being realized through applications such as autonomous operation and digital twins. SMRs can also be utilized in expanding human activity areas such as remote regions, polar areas, marine environments, deep seas, and space.

How Far Has Domestic and International Technology Development Progressed?

Currently, SMRs being developed worldwide can be categorized into pressurized water reactor (PWR) type 3.5 generation reactors and non-water-cooled 4th generation reactors. The PWR-type 3.5 generation reactors use light water (ordinary water) as coolant and moderator and use uranium dioxide (UO2) ceramic fuel with a high melting point and stability. They are integral reactors with a direct cycle design, meaning that major equipment such as pressurizers, reactors, steam generators, and coolant pumps are contained within a single vessel. This design fundamentally eliminates the possibility of core overheating or explosion accidents caused by coolant loss due to piping failure. They can use nuclear fuel enriched to 5% or less, leftover from large nuclear plants, enabling economical fuel supply. As of August last year, over 70 SMRs are under development worldwide, with 31 being this type of light water reactor SMRs. This technology has the highest maturity level and is expected to be the first to achieve commercial operation in terms of licensing and manufacturing difficulty.

In South Korea, the i-SMR passed the preliminary feasibility study in June this year. The goal is to invest 399.2 billion KRW by 2028 to complete development and begin commercialization in the 2030s. In the United States, NuScale Power's 50 MWe-class small reactor VOYGR is the most advanced. It received its first design approval in August 2020, aiming for commercial operation after 2028, and the design approval process is currently underway. The U.S. Department of Energy approved funding of $1.355 billion in October 2020. Additionally, the U.S. Department of Energy is conducting the SMR-160 project as part of its next-generation reactor demonstration program.

In the United Kingdom, the Department for Business, Energy & Industrial Strategy (BEIS) began full-scale SMR development last November with funding of ?210 million. China approved the construction plan for the ACP100 demonstration reactor in June 2021 and began building the world's first commercial land-based light water SMR, Linglong One, the following month.

Small Modular Reactor SMART developed by Korea Atomic Energy Research Institute

Active Development of Non-Water-Cooled 4th Generation Reactor Technologies

Technology development for non-water-cooled 4th generation reactors, which use substances other than water as coolant and moderator, is also active. A representative example is the sodium-cooled fast reactor promoted by TerraPower, founded by Bill Gates. South Korea has also been pursuing sodium-cooled fast reactor technology development alongside spent nuclear fuel recycling technology since 2008. There are also molten salt reactors, which use molten salt to achieve safety, economic efficiency, and efficient, economical spent fuel treatment. However, their technology maturity is still low. Globally, including the chloride salt-based conceptual research by the Korea Atomic Energy Research Institute, about 10 models are under development.

High-temperature gas reactors, lead-cooled fast reactors suitable for marine use such as nuclear submarines (including MicroURANUS developed by Ulsan National Institute of Science and Technology), and ultra-small reactors using heat pipes suitable for space and remote power sources are also being developed. Among these, MicroURANUS is a fast reactor that can operate for 40 years without refueling and is being researched to solve safety issues for use in ships and submarines. The heat pipe ultra-small reactor attracted attention by becoming the third in the world to successfully demonstrate its technology, having installed a self-developed Radioisotope Thermoelectric Generator (RTG) on the Korean launch vehicle Nuri, which was launched in June. In the hydrogen production field, core technologies for water splitting and hydrogen production using high-temperature gas reactors are also being developed.

FESTA, a small-to-medium reactor experimental facility operated by the Korea Atomic Energy Research Institute.

'Strategic Technology'... An All-Out Effort Is Needed

Experts advise that early acquisition of core technologies for next-generation reactors is essential to replace coal-fired power generation, produce hydrogen and process heat, and apply to marine and space uses. They emphasize the need to first enact support laws.

Recently, the Nuclear Energy Division of the National Research Foundation of Korea (NRF) published the "Future Next-Generation Nuclear Technology Report," urging that "to achieve early commercialization of next-generation reactors in the 2030s, it is necessary to activate R&D, advance regulations, build nuclear fuel cycle infrastructure, and enact special laws for budget support." They pointed out the need to establish institutional mechanisms that allow pre-exchange of information with regulatory agencies to streamline the endlessly long licensing periods. They suggested introducing a pre-safety review system domestically, similar to those in the U.S. and Canada. They also called for technology development led by the private sector and demand-driven approaches.

The report stated, "Since next-generation reactors can be utilized in various fields, it is more appropriate for the private sector to lead technology development in the necessary fields rather than government-led or developer-centered development," and added, "Legal and institutional support systems should be established to allow private sector participation from the early stages, and systems for joint investment should also be prepared." Along with this, the report raised the need for roadmaps and strategy development, strengthened agreements between government ministries, and a control tower capable of comprehensively supporting joint public-private research, development, and demonstration activities.