A containment building houses a nuclear reactor, coolant pumps, and other equipment. Often made of steel-reinforced concrete as an additional barrier to prevent fission material from escaping in the event of an accident. The shiny buildings of the Fukushima Daiichi Nuclear Plant have become the recognizable symbol of the earthquake’s impact on a beleaguered industry. There was significant damage to at least three of them, with an explosion that ripped off the roof of one, though the interior structure was intact. The roof and walls of another were torn. Another sustained damage, though the reactor had been shut down for maintenance.