Founded in 1992 and acquired by NUVIA since 2025, Marsein stands as a trusted leader in nuclear services and maintenance across Spain.
About us
Since its creation, Marsein has played a key role in the development of the Spanish nuclear fleet.
Today, the company provides maintenance for several facilities, such as the Vandellós II and Ascó nuclear power plants, and has also participated in the first reactor dismantling operations in Spain at the Vandellós I, José Cabrera – Zorita, and Santa María de Garoña plants.
Built on a legacy of commitment, reliability, and technical excellence, Marsein delivers innovative solutions to both public and private sectors, ensuring safety, quality, and customer satisfaction at every step.
Our expertise
Marsein excels in 3 areas: Nuclear Services, Maintenance Services, and Construction Services, providing seamless expertise across the full spectrum of nuclear and renewable energy projects.
Nuclear Services
With proven expertise in the nuclear sector, Marsein specializes in processes such as decontamination, management and control of radioactive and conventional waste, as well as the clearance and release of materials and land. For years, Marsein has successfully delivered these critical activities, ensuring operational continuity and guaranteeing the safety of facilities and the people who work in them.
Maintenance Services
Marsein is specialized in industrial cleaning—both conventional and special—along with corrosion protection and advanced coating solutions, using cutting-edge technology and highly skilled teams. Through its affiliated companies, Marsein also offers mechanical maintenance services for the energy sector, including Oil & Gas, Nuclear Power Plants, Thermal and Hydroelectric Plants, Combined Cycle facilities, and the Chemical and Petrochemical industries. Every process is executed with precision, ensuring operational reliability and complete customer satisfaction.
Construction Services
Since the very beginning, Marsein has successfully combined innovative construction technologies and solutions with traditional craftsmanship. By bringing together the best of artisanal building practices and industrialized methods, Marsein achieves its core objectives: delivering superior quality, ensuring environmental responsibility, and maintaining the highest safety standards throughout every construction process.
