Nuclear power once seemed like an energy source from a bygone era. Massive concrete domes, complex safety regulations, fear of accidents, and the problem of spent nuclear fuel made nuclear energy a cautious and burdensome subject. After the Fukushima accident, many countries classified nuclear power as a source of electricity that should be reduced, or as a risky technology to be phased out if possible. As solar and wind power expanded rapidly and carbon neutrality became a central agenda for the international community, nuclear power no longer appeared to be a leading force of the future.

But the history of energy often moves in unexpected directions. The world is now looking at nuclear power again. The reasons are not simple. Electricity demand is rising faster than expected, the climate crisis is pressuring countries to cut fossil fuels, and geopolitical conflicts are shaking energy supply chains. On top of this, artificial intelligence data centers, semiconductor plants, electric vehicles, cooling and heating demand, the battery industry, and robotic production processes are all expanding at once. Electricity is no longer just a basic living infrastructure. It is becoming a core resource of national competitiveness. There was a time when countries that secured oil led industrialization. In the future, countries that secure stable electricity are likely to lead digital industries, manufacturing, security, and climate response at the same time.

The reassessment of nuclear power, therefore, is not a simple debate over whether one supports or opposes nuclear energy. More precisely, it is a question of what kind of power system a country should have in an age when electricity itself has become security. This does not mean nuclear power is a perfect answer. Nuclear energy still carries problems of risk, cost, waste, and local acceptance. Yet as electricity demand surges, carbon emissions must be reduced, and grid stability must be maintained, the view is growing that excluding nuclear power entirely is also unrealistic. Nuclear power is once again becoming a card for the future. This return, however, is different from the past. It is not only large-scale nuclear power plants that are being discussed, but also small modular reactors, or SMRs. Nuclear power is being repositioned not as a solo star, but as one pillar of a complex power system that works together with renewable energy, storage systems, transmission grids, and demand management.

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In the twentieth century, national competitiveness began with oil, steel, ports, roads, and large industrial zones. Countries grew by bringing in enough raw materials, running factories with inexpensive energy, and transporting products quickly. But as we move deeper into the twenty-first century, the starting point of competitiveness is increasingly shifting toward electricity. Electricity is no longer limited to the household energy that powers lights and refrigerators. Almost every core infrastructure now runs on electricity, including servers that train artificial intelligence, semiconductor clean rooms, electric vehicle charging networks, battery factories, smart logistics warehouses, robotic production lines, desalination facilities, and military communications networks.

Artificial intelligence, in particular, has brought the issue of electricity to the forefront. For a long time, the digital industry seemed light and clean. Software and platforms grew without smokestacks, and the cloud was perceived as a service with an almost invisible physical foundation. But with the rise of generative artificial intelligence, the material base of the digital industry has been revealed. Artificial intelligence does not run on invisible algorithms alone. It requires massive data centers, high-performance semiconductors, cooling systems, transmission grids, substations, and long-term power purchase agreements. Data centers are no longer the back room of the internet. They have become enormous electricity consumers that can shake regional power grids.

The problem is that the speed at which electricity demand is rising is different from the speed at which power supply systems can change. Data centers and factories can be built within a few years. But transmission grids and large power plants take much longer. Renewable energy is expanding quickly, but its output changes depending on weather and time of day. Batteries are essential for reducing this variability, but in terms of cost and technology, they still have limitations in fully handling long-duration and large-scale storage. Natural gas power plants can be deployed quickly, but they still face price volatility and carbon emissions problems. It is precisely in this gap that nuclear power is being called upon again. Once in operation, nuclear power can supply large amounts of electricity steadily over a long period, and it produces little carbon during power generation.

It is no longer enough simply to produce a lot of electricity. Electricity must not be interrupted, its price must be predictable, and its carbon emissions must be low. Industries avoid places with unstable electricity prices, data centers move in search of stable power contracts, and countries are realizing that when the power grid becomes unstable, security also becomes unstable. Electricity has become an invisible border. A country short of electricity will find it difficult to attract advanced industries, and a country with surging electricity prices will struggle to protect its manufacturing competitiveness. The industrial map of the future is likely to be redrawn not only around airports, ports, and roads, but also around power plants, transmission grids, and electricity storage facilities.

After the Fukushima accident, nuclear power became a politically burdensome energy source in many countries. Even if the probability of a nuclear accident is low, the social shock is enormous once it happens. Fear of radioactive materials is not easily resolved by technical explanations alone. The question of where, how safely, and for how long spent nuclear fuel should be stored is also far from simple. For these reasons, nuclear power was long seen as a risk that should be reduced. In some countries, nuclear phase-out was accepted almost as the spirit of the times, and expectations grew that renewable energy and energy efficiency improvements would replace nuclear power.

But energy policy does not move by ideals alone. The war between Russia and Ukraine showed the world once again the reality of energy security. Natural gas prices soared, electricity bills rose, and industries came under cost pressure. It became clear that energy is both a commodity traded in markets and a tool of politics and security. Countries now face the contradictory task of reducing dependence on fossil fuels while also securing stable electricity. To cut carbon emissions, they must expand electric vehicles, heat pumps, and industrial electrification. But how to produce enough stable electricity for all of this has become another major challenge.

The logic of nuclear phase-out had strong persuasive power from the perspectives of safety and the environment. But in the face of continuously rising electricity demand, that logic has encountered new questions. What will fill the space left by reduced nuclear power? Can a twenty-four-hour stable power grid be operated with renewable energy alone while reducing coal and gas? If nuclear power is reduced too quickly before transmission grids and storage systems are sufficiently prepared, what happens to electricity prices and industrial competitiveness? When climate response and electricity security collide, which should be prioritized?

Of course, these questions do not automatically guarantee that expanding nuclear power is the answer. They simply mean that the situation has become too complex to push nuclear power aside as merely an energy source of the past. Earlier debates over nuclear phase-out centered on the risks of nuclear energy. Today’s reassessment of nuclear power is taking place within a much broader framework that includes electricity demand, carbon neutrality, energy security, and industrial competitiveness. Nuclear power is not being reconsidered because people suddenly like it. It is being reconsidered because, when nuclear power is removed from the equation, the remaining gap looks too large.

At the center of the nuclear debate are still large nuclear power plants. Their advantages are clear. Once a large reactor is completed, it can generate enormous amounts of electricity reliably for decades. It does not require frequent fuel replacement, produces large output, and is not affected by weather. Countries with high electricity demand, especially those with manufacturing sectors such as semiconductors, steel, chemicals, and batteries, cannot easily give up this stability. Factories and data centers are not facilities that operate only when electricity is available. They need predictable electricity twenty-four hours a day, 365 days a year. Large nuclear power plants are among the power sources closest to meeting this requirement.

But large nuclear power plants are not an easy choice. They require long construction periods and high initial investment. If construction is delayed or costs exceed estimates, the political burden grows. Building a nuclear power plant is not simply a power station construction project. It is an extremely long-term national project involving finance, regulation, safety review, local acceptance, workforce training, and supply chain management. In democratic countries, large nuclear projects become vulnerable whenever policy consistency is shaken. If nuclear policy swings back and forth every time a government changes, companies delay investment, skilled workers leave, and supply chains weaken. Nuclear power is not a switch that can simply be turned back on overnight. Once the industrial ecosystem collapses, recovery takes a long time.

Even so, large nuclear power plants are being discussed again because of the scale of electricity demand. The demand created by artificial intelligence and electrification cannot be solved by small supplementary power sources alone. Large industrial complexes, metropolitan areas, and advanced manufacturing clusters require enormous amounts of electricity. Even if renewable energy is expanded as much as possible, cloudy days, windless hours, nighttime demand, and seasonal variation mean that the power grid needs a stable central axis. Large nuclear power plants can serve as that axis.

The return of large nuclear power plants does not mean going back to the old way. Future large nuclear projects will be required to meet stricter safety standards, provide more transparent information, develop more sophisticated financial structures, and build stronger local consultation systems. It is not enough to insist that nuclear power is technically safe. Society must be able to accept that it is safe. The economics of nuclear power also cannot be assessed only by the cost of generation. Long-term stable electricity supply, carbon reduction, grid stability, and the effect of attracting industries must all be considered. At the same time, cost overruns, waste management, and accident response costs must also be included. Reassessing nuclear power is not about glorifying it again. It is a process that demands a far colder and broader calculation.

The term that appears most often in recent nuclear discussions is small modular reactor, or SMR. SMRs are drawing attention because they are expected to reduce some of the long-standing weaknesses of nuclear power. Conventional large nuclear power plants are massive, and because they involve a great deal of site-specific construction, process management is difficult. By contrast, SMRs aim to use relatively small reactors manufactured in standardized form at factories and assembled on site. In theory, this can shorten construction periods, lower initial investment burdens, and allow multiple units to be deployed in stages as needed. If a large nuclear power plant is like a giant dam, an SMR is closer to a modular power block that can be placed in multiple locations.

SMRs appear especially attractive in places where large power grids are difficult to reach or where there is special electricity demand. Examples include remote areas, islands, military bases, industrial complexes, desalination facilities, district heating systems, hydrogen production sites, and data centers. Data centers, for example, must secure vast amounts of electricity reliably while also facing pressure to reduce carbon emissions. Renewable power purchases alone cannot fully match twenty-four-hour electricity demand. In this situation, SMRs are emerging with the image of an always-on low-carbon power source. The idea of placing a stable power source next to a data center is no longer science fiction. It is now being discussed as part of real industrial strategy.

Of course, SMRs are still somewhere between promise and reality. Their technological potential is large, but commercial verification remains insufficient. Many questions still need to be answered. How low will actual costs become? How quickly will the economies of scale from factory production work? How will regulatory review be standardized? How will spent fuel and safety issues be handled? A smaller nuclear reactor does not automatically mean that risk disappears. If reactors are distributed across multiple regions, security, monitoring, and emergency response systems must become even more sophisticated. Just because nuclear reactors become smaller does not mean social responsibility becomes smaller as well.

Still, SMRs matter because they are changing the imagination of energy policy. Nuclear power no longer means only a massive power station built on the coast. It is beginning to be discussed as a distributed low-carbon infrastructure that can be placed closer to electricity demand, tailored to the structure of industries and cities, and used to supply both heat and electricity. This could change the image of nuclear power itself. If nuclear power has traditionally been a huge pillar of the national power grid, SMRs may become customized power sources for industrial sites and local regions. But that possibility still needs to be proven. The future of SMRs depends not on promotional language, but on the success or failure of the first commercial examples that actually operate.

The debate over nuclear power will not end easily. Supporters of nuclear energy argue that it is one of the few large-scale power sources capable of reducing carbon emissions while also providing stable electricity. Solar and wind power must be expanded rapidly, but because they are affected by weather and time, stable power sources such as nuclear energy are needed. In particular, if the power grid becomes unstable, industry and daily life can both stop. Therefore, the argument goes, nuclear power cannot be excluded when climate response and electricity security are considered together.

Critics of nuclear power, on the other hand, argue that it is too expensive, too slow, and too dangerous. New nuclear power plants take a long time to complete, and cost overruns can occur repeatedly. In many countries, spent fuel disposal sites still struggle to gain social consent. Even if the probability of an accident has decreased, it has not disappeared entirely. There is also concern that if huge budgets are spent on nuclear power, fewer resources will be available for renewable energy, transmission grids, batteries, and energy efficiency improvements.

What matters in this debate is the attitude of neither mythologizing nor demonizing nuclear power. Nuclear power is not the answer to every problem. But in an era of surging electricity demand, excluding it entirely is also unrealistic. Nuclear power is a technology with powerful advantages and heavy responsibilities. Therefore, the question should not stop at whether to use nuclear power or not. We must ask what kind of nuclear power, where, at what scale, under what regulations and oversight, and within what combination of power systems it should be operated.

The climate value of nuclear power is clear. It produces almost no carbon during electricity generation and supplies power for long periods regardless of weather. But calling it a climate solution does not make all problems disappear. High-level radioactive waste, decommissioning costs, accident response systems, local acceptance, and regulatory independence remain central challenges. The future of nuclear power is not only a matter of technology. It is also a matter of trust. People are more sensitive not to explanations that nuclear power is safe, but to who will take responsibility and how they will respond if a risk occurs. Nuclear power is not merely a facility that produces electricity. It is a public technology that tests society’s ability to manage risk.

Future energy strategy will depend more on the sophistication of combinations than on a single answer. Solar and wind power must continue to expand. Batteries, pumped hydro storage, hydrogen storage, and demand response technologies must also be strengthened. Investment in transmission grids must accelerate, and electricity consumption efficiency must improve. If nuclear power is included on top of this, it should be designed not as a competitor that pushes out renewable energy, but as a pillar that supports grid stability. For the reassessment of nuclear power to be meaningful, it must lead not to the revival of nuclear power alone, but to the redesign of the entire power system.

Korea occupies a special position in the nuclear debate. It has a small land area, lacks domestic energy resources, and has a high share of manufacturing. Semiconductors, displays, steel, petrochemicals, batteries, shipbuilding, automobiles, and data centers all require stable electricity. The Korean economy stands on industries that consume large amounts of power. Electricity prices and power quality are directly tied to industrial competitiveness. If Korea loses electricity security, its entire industrial strategy will inevitably be shaken.

At the same time, Korea has experience in building and operating nuclear power plants. It has accumulated capabilities in design, manufacturing, construction, operation, maintenance, and parts supply chains, and it has experience exporting nuclear power plants overseas. The global reassessment of nuclear power could become an opportunity for Korean companies and the broader industrial ecosystem. New markets could open in large nuclear plant exports, nuclear components, operation and maintenance, SMR technology development, nuclear decommissioning, and radioactive waste management. Nuclear power can become not only a source of electricity, but also an export industry and a pillar of advanced manufacturing.

But there are not only opportunities. The biggest issue is policy consistency. Nuclear power cannot be handled as a five-year policy. Planning, building, operating, and decommissioning a nuclear power plant takes decades. The same is true of workforce training. Once experts in universities, research institutes, and companies leave the field, rebuilding that human base is difficult. If nuclear policy swings sharply with every change of government, the industrial ecosystem cannot make long-term investments. For nuclear power to become a card of electricity security, it must be treated not as a political slogan but as a national power strategy.

The issue of spent nuclear fuel can no longer be postponed. Trust in nuclear power is not determined only inside the power plant. How a country manages the high-level radioactive waste that remains after electricity generation determines the legitimacy of nuclear policy. Continuing to expand temporary storage facilities alone cannot win social trust. Long-term disposal sites, regional compensation, transparent information disclosure, independent regulation, and resident participation must go together. If a country speaks of expanding nuclear power, it must also speak of responsibility for waste management. The real cost of nuclear power is revealed not at the moment a power plant is built, but in the ability to take responsibility for decades afterward.

SMRs are also both an opportunity and a test for Korea. If Korea wants to develop SMRs into a future export industry, technology development alone will not be enough. Safety regulation systems, standardized designs, demonstration sites, financing models, overseas certification, international cooperation, and supply chain strategies are all necessary. Because the SMR market has not fully opened yet, what matters is who can first prove safety and economic viability. More important than technological promotion is the first actual case that works. In the nuclear industry, trust is built not by words but by operating records.

It is also important whether Korean society can move beyond the pendulum swing of support and opposition over nuclear power. The argument that nuclear power is dangerous and should all be reduced oversimplifies reality. So does the argument that nuclear power alone is the future. What Korea needs is a colder and more realistic power strategy. It must discuss at the same time how much nuclear power is needed, how far renewable energy can be expanded, how transmission grids should be reinforced, how electricity demand from industrial complexes should be managed, how the electricity pricing system should change, and how spent nuclear fuel should be handled responsibly. Nuclear power is one piece of this large puzzle. What matters is where that piece should be placed and how large it should be.

The future energy order will become increasingly difficult to explain through a simple confrontation between nuclear power and renewable energy. Renewable energy will grow larger. Batteries and storage technologies will also advance. Electric vehicles, heat pumps, data centers, and artificial intelligence will continue to push up electricity demand. At the same time, the climate crisis will pressure countries to reduce fossil fuels. In this complex equation, nuclear power is emerging again as one realistic option.

But the reassessment of nuclear power is not a return to the past. In the past, nuclear power was a device for supplying electricity during the era of large-scale industrialization. In the future, nuclear power will become a complex infrastructure where electricity security, carbon neutrality, digital infrastructure, local acceptance, and risk management are intertwined. Nuclear power must become more transparent, safer, and more flexible. The nuclear industry can no longer remain only the domain of engineers and governments. It must become a public technology tested together by citizens, local communities, financial markets, industries, and environmental policy.

The most realistic future is unlikely to be one in which a single energy source solves every problem. Solar and wind power may take up a large share of electricity. Batteries and storage technologies may absorb variability. Nuclear power may serve as a long-duration stable power source. Gas may remain as a transitional supplementary source. Demand management may adjust consumption. The future of energy is not a story in which one hero solves every problem. It is closer to a story of several technologies complementing one another’s weaknesses.

The core issue behind the return of nuclear power is ultimately this. In an age when electricity itself has become security, what kind of power system should a country have? The era of searching only for the cheapest electricity is passing. What matters now is electricity that is affordable yet stable, clean yet sufficient, expandable yet socially manageable. There is no single power source that satisfies all these difficult conditions. That is why the reassessment of nuclear power has meaning within a broader power strategy.

Nuclear power is returning. But this is not an unconditional revival. It is a return that is possible only through colder calculations, stricter safety, more transparent consensus, and more sophisticated power grid design. Whether nuclear power can become a card for the future depends not only on the technology of nuclear power itself, but also on society’s ability to manage risk and maintain a long-term strategy. In the age of electricity security, nuclear power is once again on the test bench. The standard of this test is not simply the amount of electricity generated. The future of nuclear power will be decided by whether it can bear stability and responsibility, cost and trust, all at once.

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