Three Mile Island

three-mile-islandThe nuclear engineer inside of me loved this post on the Three Mile Island event on March 28, 1979. Here’s my favorite part:

Suppose in learning to drive a car you are being trained to respond to the car veering to the left. It’s simple enough, simply turn the steering wheel to the right to recover. It is also what your basic instinct would lead you to do, so there is no mental conflict in believing it.

It is also actually reinforced and practiced during actual driver training on a curvy road. That response is soon imbedded as the right thing to do. Now suppose your driver training also includes training on a car simulator training machine. It is where you learn and practice emergency situation driving. After all, nobody is going to do those emergency things in an actual car on the road.

Here’s where it gets complicated. Assume virtually no one yet understands that when the car skids to the left on ice (because of loss of front wheel steering traction), the correct response is to turn the steering wheel into the skid direction, or to the left. This is just the opposite of the non-ice response. And to make matters worse, because no one understands it yet, including the guy who built the car simulator, the car simulator has been programmed to make this wrong response work correctly on the simulator.

So in your emergency driver training you practice it this way, the simulator responds wrong to the actual phenomena, but it shows the successful result and you recover control. Since this probably also agrees with your instinct, and you see success on the simulator, this action is also embedded as the right thing to do. One additional point, if you don’t do this wrong action, you will flunk your simulator driver training test.

You know where this is going, now you are out driving on an icy road for the first time and the car skids to the left. You respond exactly as you were instructed to do and exactly as the simulator showed was successful, and you have an accident because the car responds to the real world rules of Mother Nature.

An investigation is obviously necessary because, I forgot to tell you, the car cost $4 billion and you don’t own it. During the subsequent investigation everything is uncovered; the unknown phenomenon is finally correctly understood, the simulator incorrect programming is discovered, it is uncovered that the previously unknown phenomenon had been discovered before your accident, and your accident was even predicted as possible.

But the investigation results are published and the finding is that the accident was caused by your error of turning the steering wheel the wrong way on the ice. Nobody else is found to have made an error in the stated conclusions but you; it is simply a case of driver error. Do you feel you have been wronged? This is what happened to the TMI operators.

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