Everyone is rightfully concerned about Japan and what is to become of the region around the Fukushima Dai’ichi generating station. The quality of information by the various broadcast outlets is improving somewhat in my estimation. What the rest of the world should take note of is the stoic and highly admirable manner in which the Japanese have responded to the earthquake*tsunami*nuclear-disaster trifecta that has fallen upon them. In a US city there’d be looting and widespread felonious mischief as local criminal entrepreneurs rose to the occasion.

Another thing that I hope is noticed is the manner in which the failures initiated and propagated at the power station.  The unfortunate low elevation of the emergency generators is the obvious one.  But there is something else that is dramatically affecting how the incident propagates.  If you look at the cutaway diagrams of the plant you will see the highly compact nature of the facility.  The footprint of the buildings are quite small given the amount of equipment and processing that occurs there. In particular, the location of the cooling pools for the spent fuel assemblies is at the upper level of the structure, above the reactor spaces. 

The upper level with the cooling pools has an overhead crane that can move along the length of the facility. The fuel elements can be pulled up and out of the reactor and moved laterally into the pool.   The General Electric design is quite efficient in the use of acreage. But in the event of a major upset with fire, explosions, major radioactive material release, and structural damage, the compactness of the facility and the elevation of the spent fuel cooling pools works for prolonged incident propagation and against termination. 

The very altitude of the cooling pool spaces presents a major hurdle to taking control of the situation.  Having this problem at ground level where you could directly apply resources to the event would be bad enough. But to have it many stories above ground places huge constraints on the responders.  Designers of power plants should be thinking about where hazardous energy can be released and how responders will deal with it. Problem- all facilities design projects are constrained by severe cost considerations. Designers prefer to think about the most efficient designs, not how their brain child is going to fail.

Advertisements