Construction of the outer containment of the reactor building has been completed at the Leningrad 2-2 VVER-1200 nuclear power unit under construction in western Russia, state nuclear corporation Rosatom said.The outer containment is designed to protect the reactor installation from external influences such as earthquakes, storms, explosions and aircraft impact.Rosatom said that because of the importance of the outer containment additional controls were put in place during construction.