Three Mile Island Revisited

I sometimes find inspiration for posts in diverse locations. This time the inspiration happened to be a photograph of an ultralight plane that I took last July at EAA AirVenture.

Air Instrument system 2The photo is of the engine of an ultralight aircraft; a converted two cylinder VW. In the middle of the photo is the tube for the oil pressure gage coming from the oil gallery on the engine block and running to the pressure gage on the panel (dashboard) of the plane. Notice that the clear tube has oil and air in it. When the engine is started, the oil pump will deliver oil to the gallery, which will compress the air in the tube and probably add more oil to the tube also. The oil pressure gage will correctly display the engine oil pressure even though there is a mix of oil and air in the tube.

Air can be considered a fluid for this discussion and oil is also a fluid. The air will compress, meaning its volume will decrease in proportion to the pressure, while the oil is essentially incompressible. The oil will transmit the pressure applied to it on one end of the tube to the other end of the tube. In this case where there is oil and air in the tube. The bits of oil will get closer together as the air between the oil is compressed.

What does this have to do with Three Mile Island? A lot, actually.

On March 28, 1978 at 4 am, Three Mile Island (TMI) Unit 2 went critical for the first time after it had been completed. It went into commercial production until March 28, 1979 at 4 am when a transient in the system caused an event that eventually lead to the partial meltdown of the core and the complete loss of the unit. Yes, you read that right. Exactly one year to the minute between first criticality and the “accident”.

The transient that started the whole chain of events was blamed on water in the air instrument system that monitored the plant and operated the valves that controlled the entire unit.

Why was there water in the air instrument system? Because someone connected a high pressure water hose to the air instrument system, thereby introducing water into the air system. Who did this? Both official reports of the accident did not determine who.

I have one additional question. Why would water in the air instrument system cause valves to close simultaneously?

As shown in the photo above, two fluids in the oil pressure sensor tube transmit pressure just fine. Though I have no specific knowledge of the air instrument system at TMI 2, I don’t get why some water in the air system makes a lot of valves close simultaneously. (I do get the fact that the aircraft system shown in my photo has no pressure actuated valves and is very simple.)

Why does this matter? Isn’t this ancient history?

I believe that fear is the number one reason that the average Joe or Jane is opposed to nuclear power and by that I mean peaceful, commercial nuclear power – the kind that powers your computer and hair dryer, the kind that Joe six-pack needs if his lifestyle is not to revert to pre-industrial levels.

That fear is learned and comes mostly from public schools and the establishment media, who have their reasons for instilling that fear.  I speak from experience regarding public schools (and the media). I attended them myself and my 5 kids attended them.

Their science books were generally published by National Geographic and were dismissive of nuclear power, usually with words like, nuclear power originally showed great promise, but their waste problem remains unsolved. And besides, with wind, solar, and water power, we don’t need dangerous nuclear power. Or some such nonsense.

The media adds to this anti-nuclear fear constantly (just think of their coverage of Fukushima) and was very guilty in their woeful coverage of the Three Mile Island (TMI) accident.

This is why the cause of the transient at TMI Unit 2 matters. Let me end this post with a quote:

On August 3, 1979 in its official report on the event, the U.S. Nuclear Regulatory Commission posed sabotage or criminal negligence as one of six possible causes for the Three-Mile Island event. But even after eliminating the other five possible causes, the government refused even to consider the possibility of sabotage seriously.
(Engdahl, F. William, A Century of War: Anglo-American Oil Politics and the New World Order 2012 Pg 210)

If this post was interesting to you, I recommend that you go to Atomic Insights to read more about TMI Unit 2.


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