Japanese light water reactors had obvious design and installation issues

by Tom Devanney

The recent March 11th 9.0 Earthquake in Northeastern Japan caused serious damage to the Fukushima Nuclear Power station at Sendai.  This picture shows the installation before the catastrophic event. The four large tall square buildings are the reactor containment buildings. The light water reactors (LWR) inside generated most of northern Japan’s electrical power for industrial and residential use. They are at best, 15 feet above sea level.

The reactor containment buildings are lined up behind the pumping and control buildings. The reactors are completely safe, as long as the cooling mechanism and backup power are working. There are obvious issues with the plant design and installation.

  1. Site Selection and design. There are possible site selection flaws.  The containment buildings are lined up like pins in a bowling alley.  This subjects them to a tsunami that is barely 25 feet high, let along the March 18th wave of 70+ feet.  The tsunami scraped the entire installation to ground level save the concrete containment structures.  Backup power was at ground level.   The tidal wave put it under water and rendered it useless.   It takes seven days to cool a light water reactor down to ambient temperature.
  2. Nuclear Reactor Type. There are several types, gas cooled, light water, heavy water, and pebble bed.  The Fukushima light water reactors are safe and efficient if used in a location where they are not subject to tsunami wave action.  A better reactor design for this installation probably would be gas cooled. Gas cooled reactors would have not generated a hydrogen bubble after backup power was lost.  The resulting loss of power also subjected the spent fuel storage facility in all units to overheating.  Fukushima was a disaster waiting to happen.
  3. Power Generating Cost. Nuclear energy costs are now leaning in favor of nuclear power.  Current light water and gas cooled energy generating costs are about even.  In 1962 however, light water reactors were the answer.  GE and other reactor manufacturers were committed to light water.  There are nuclear waste issues, but disposal of both types are about the same.  On site storage of spent fuel is the standard.  Studies have shown that both types are currently close in energy cost.

The problem with Fukushima was a combination of several factors.  If the site selection alone were addressed, the plant would have been spared.  Safe to say, the nuclear power industry will never be the same again.

The websites below are available to research issues with nuclear power.  A basic approach is to evaluate seismic issues, address site location, insure an adequate source of water for backup and emergency use, and a study of which type of nuclear reactor best suits the market.

This picture serves as a warning to what can happen when simple common engineering sense is ignored.


Research issues with nuclear power

Gas cooled






Pebble Bed