The world's first vertical modular spent nuclear fuel dry storage model (COSMOS), developed by Korea Hydro & Nuclear Power Company (KHNP), has recently drawn attention from the domestic and international nuclear power industry. With its innovative design and technological advantages, the system is considered a viable solution to the shortage of spent fuel storage space and is planned for export to overseas markets.

KHNP completed the conceptual design of COSMOS in 2019 and finalized the detailed design of a 240-unit storage system in 2022. The company is currently advancing design optimization for a 370-unit storage system, aiming to complete technical standardization by the end of this year to enable commercial application. In addition, KHNP plans to submit a license application to the U.S. Nuclear Regulatory Commission (NRC) in 2026 to pave the way for entering the U.S. market.

Against the backdrop of spent fuel storage space reaching capacity in nuclear power plants in countries such as Japan, COSMOS breaks through the structural limitations of traditional cylindrical storage containers, offering safety, economic efficiency, and scalability. Each COSMOS module can store about 370 spent fuel bundles, improving on-site efficiency by up to 30% compared with commercial storage containers in countries such as the United States. The design can withstand external impacts such as large aircraft crashes, earthquakes of 0.3g or higher, and extreme weather, without the need for additional protective buildings, significantly reducing construction costs.

In addition, COSMOS modules adopt a fully sealed structure that effectively prevents salt corrosion in coastal storage facilities, and maintenance requires only container replacement, making operation simple. Its modular design allows flexible expansion according to national needs to accommodate various storage scenarios.

KHNP's technological capability has gained international recognition. At the International Power Technology Exposition (BIXPO) in 2022 and the international invention competitions held in Indonesia in 2024 and Switzerland in 2025, technologies related to COSMOS won multiple awards including grand prizes, gold prizes, and special awards.

Shin Ho-cheol, Director of KHNP's Central Research Institute, stated that the company will continue to monitor global high-level radioactive waste management technology trends and promote the internationalization of Korean technology. He noted that COSMOS reduces costs by 20% to 50% compared with existing commercial models. If approved by the NRC, it will accelerate its global market expansion, with nuclear power demand countries, including the United States, likely to become target markets.

KHNP is currently in discussions with nuclear power companies and regulatory agencies in multiple countries to advance technical validation and commercial cooperation for COSMOS.