The New Safe Confinement design is an arch-shaped steel structure with an internal height of and a distance between the centers of the upper and lower arch chords. The internal span of the arch is , and the external span is . The dimensions of the arch were determined based on the need to operate equipment inside the new shelter and decommission the existing shelter. The overall length of the structure is , consisting of 13 arches assembled apart to form 12 bays. Vertical walls assembled around, but not supported by the existing structures of the reactor building seal the ends of the structure.