Your article is a bit confused in the way it describes nuclear power plant containment. The description includes the cooling system as well.
The inside of the containment structure is highly complex; it consists of high-pressure pipes which both prevent the leak of radioactive fuel and cool down the fuel in the event that the reactor has to be shutdown.
Containment means the concrete and steel vessels that surround the reactor.
When I tried to find reference 4 in the article you linked, I got a "404 not found." That's a critical reference in the article's claims.
Here's another article that describes a study on the danger of airplane crashes into reactor containment buildings.
Separate analyses assumed direct hits by both the aircraft’s fuselage and a 9,500-pound engine. This size engine is typical of the majority of aircraft currently in service; it would envelop engines on 767-400s, 757-300s, 747-400s, 737-800s, DC 10-30s, MD11s, A320-200s, A330-200s and L1011-500s.
This confidence [that the reactor containment would survive such a hit] is predicated on the fact that nuclear plant structures have thick concrete walls with heavy reinforcing steel and are designed to withstand large earthquakes, extreme overpressures and hurricane force winds.
Last Edit: 19 Jan 2013 20:33 by Cheryl. Reason: copyedit