IDOM carried out the technical support to the operation of Santa María de Garoña Nuclear Power Plant focusing on four engineering disciplines; electricity, instrumentation, mechanics and structure providing support at different departments: electrical maintenance, mechanical maintenance, instrumentation maintenance, engineering, mechanical engineering, structures, systems and training. The works consisted mainly in the design and development of Design Modifications (MD), technical and economic feasibility studies of the MDs, analysis of operating experience, training of Nuclenor staff in the field of instrumentation maintenance, seismic validation studies on structures (piping and component supports), and complete system studies (e.g. fire safety).