Chronology of a Disaster: Earthquake, Tsunami, Nuclear Emergency
Friday, March 11, 2011
2:45PM: Earthquake off the coast of Japan
4:00PM: A 10-meter-high wall of water slams northeast Japanese Coast including Fukushima I Nuclear Power Plant
6:30 PM: Cooling system fails in one reactor at Fukushima
11:40 PM: Emergency cooling system running on auxiliary power
Saturday, March 12, 2011
7:00 AM: I AEA announces 2nd reactor cooling system at Fukushima damaged
Sunday, March 13, 2011
8:00 AM: Cooling system fails in a third reactor block at Fukushima
Source: Deutsche Presse-Agentur March 14, 2011
“Emergency power supply system…tanks seem to have been damaged or destroyed because of Tsunami.”
Source: The Denki Shimbun: The Electric Daily News. March 18, 2011.
Interpreting this chain of events, it’s obvious that the earthquake spawned the Tsunami that struck the power plant crippling the cooling systems for the nuclear reactors. When the power was knocked out, the emergency generators needed to engage to run the pumps for the cooling system. As reported the auxiliary power did deploy, but systematically all of the cooling systems failed. The weak link seems to be the fuel tanks. In retrospect this makes sense since the generators should have been housed in reinforced buildings whereas the fuel tanks would have been outside exposed to the environment.
Fuel tanks are vented to the atmosphere to relieve pressure. The vent and any other non-airtight openings allow water into the tank. Once water enters the tank it sinks to the bottom displacing the fuel. The problem with standard fueling system is that the fuel pick up line is located at the bottom of the tank. During water intrusion, it doesn’t take long for the water level to rise 3” to 5” to reach the fuel pick up point. Consequently, water is pumped to the engine, shutting it down.
A smarter way to dispense fuel for critical systems is to utilize a floating suction line which provides fuel away from the contamination zone of a tank. The FLOATube™ is just such a passive safety device which depends strictly on physics to operate. A FLOATube™ is a floating fuel pick up line which is plumbed at the center of the tank. It maintains its position relative to the fuel as the volume changes. The FLOATube™ provides the cleanest fuel in the tank at all times. Since fuel is pulled from the center of the tank as opposed to the bottom, the FLOATube™ allows more time to react to problems associated with water intrusion. The Airline Industry requires that fuel tanks have floating suction lines. It may be time for the Nuclear Industry to adopt the same standards. Ensuring a clean fuel source may avert a major catastrophe.