"At 28, 000 feet, you don't have an awful lot of useful consciousness without the support of oxygen or being in a pressurized aircraft, " said O'Brien, a former CNN correspondent.

CNN: SHARE THIS

It is the AP 1000 reactor, a pressurized water reactor, sold by Westinghouse Electric Co.

WSJ: GE Steps Up Aid in Reactor Crisis

The rain simulator has 4 in-line spray nozzles, which are feed by a pressurized portable pipe system.

UNESCO: AQUATACAMA