"Is Nuclear Power Expensive and Inflexible?"... The Korean Nuclear Society Counters with the Numbers

Settlement Price at 66.3 KRW, Grid Inertia, and Output Adjustment:
Fact-Checking the Debate on New Nuclear Power Plants

The Korean Nuclear Society has welcomed the government's decision to proceed with the construction of new nuclear power plants as included in the 11th Basic Plan for Long-term Electricity Supply and Demand, and has released a fact-check document based on scientific evidence to counter some anti-nuclear arguments. The society stated that this decision is a rational choice that simultaneously considers the national challenges of decarbonization and energy security, and emphasized that additional new nuclear plants should also be reflected in the upcoming 12th Basic Plan for Long-term Electricity Supply and Demand.

View of the construction of Units 3 and 4 at the Saeul Nuclear Power Plant. Photo by Yonhap News Agency

In a statement released on the 26th, the society said, "With mid- to long-term electricity demand expected to surge due to the development of the AI industry and the establishment of semiconductor clusters, securing a stable and low-carbon power supply is not a choice but a necessity," adding, "The decision to confirm the construction of new nuclear power plants in the 11th Basic Plan is a policy judgment that reflects reality."

In particular, the society pointed out that the debate surrounding new nuclear plant construction is spreading based on misunderstandings and perceptions rather than technical facts. It addressed key issues such as the load-following capability (flexibility) of nuclear power plants, economic feasibility, power grid stability, safety, and spent nuclear fuel management. The society shares a common concern that discussions should be grounded in objective data and engineering evidence, rather than emotional arguments.

First, regarding the claim that "nuclear power plants cannot adjust output and therefore cannot coexist with renewables," the society clarified that this is not technically accurate. The APR1400, which is the main domestic reactor type, was developed with load-following operation and output adjustment capabilities in mind from the design stage. The society explained that improvements are underway to further expand the range of output adjustment in response to fluctuations in renewable energy generation.

The society also stressed that cases of output reduction at French nuclear plants, often cited by opponents, should be seen not as a result of technical flaws but as "system operation outcomes," where nuclear plants adjusted output to stabilize the grid during periods of high renewable generation.

On the issue of economic feasibility, the society pointed out that the basis for comparison is fundamentally flawed. Claims that renewables are cheaper than nuclear power are based solely on the generation cost of the plants themselves, whereas the actual power system must also consider additional "system costs" such as grid reinforcement and backup facility construction.

Especially as of 2024, the settlement price for nuclear power in the electricity market is 66.3 KRW/kWh, which is significantly lower than LNG (175.5 KRW/kWh) and the average for renewables (138.8 KRW/kWh, excluding REC), thereby contributing to electricity price stability. The society asserted that when considering the total system cost, including grid integration costs rather than just the simple levelized cost of electricity (LCOE), the economic advantage of nuclear power becomes even clearer.

In response to concerns that the shutdown of a large nuclear unit could threaten the power grid, the society highlighted that nuclear power actually plays a major role in grid stability. As a large rotating generator, nuclear power provides physical "inertia" that mitigates rapid frequency changes, whereas solar and wind are structurally limited in this function. The society stated that discussions on grid stability must consider not just installed capacity, but also power quality and physical characteristics.

Based on this perspective, the society also raised the need for a proactive response in the upcoming 12th Basic Plan for Long-term Electricity Supply and Demand. Although the plan period extends to 2040, considering the 2050 carbon neutrality goal, new nuclear plants must serve as a "bridgehead" for mid- to long-term energy transition. Given the time required for permitting and construction, the society argued that new nuclear plants targeted for operation in 2039-2040 should be included in the plan now. The society also sees small modular reactors (SMRs), along with large nuclear plants, as playing an important role in the future power mix.

Choi Sungmin, President of the Korean Nuclear Society, said, "Nuclear power is not a source that hinders renewables, but rather complements their variability and serves as a foundational power source supporting both carbon neutrality and advanced industries such as AI and semiconductors." He added, "Energy policy discussions should be based on objective data and scientific facts, not unscientific claims or ideological debates."

This content was produced with the assistance of AI translation services.