Accidents do happen..............

On a recent holiday I was reading yet another of Malcolm Gladwells books--which include The Outliers and Tipping Point.---All his books are amazing and really challenge our thoughts and conventions.

Anyway, the book concerned is "What the Dog Saw"--The chapter is titled Blowup---Who can be blamed for a disaster like The Challenger Explosion? No one and we'd better get used to it.

He goes on to explain what caused the Three Mile Island ( TMI) problem and these are words straight out of the book---Thank you Malcolm---

"--the near disaster at the TMI nuclear-power plant in March 1979. The conclusion of the president's commission that investigated the TMI accident was that it was as the result of human error, particularly on the part of the plant's operators. But the truth of what happened there, the revisionists maintain,is a good deal more complicated than that, and their arguments are worth examining in detail.

The trouble at TMI started with a blockage in what is called the plant's polisher-a kind of giant water filter. Polisher problems were not unusual at TMI, or particularly serious. But in this case the blockage caused moisture to leak into the plant's air system, inadvertently tripping two valves and shutting down the flow of cold water into the plant's steam generator.

As it happens, TMI had a back up cooling system for precisely this situation. But on that particular day, for reasons no one really knows, the valves for the back-up system weren't open. They had been closed, and an indicator in the control room showing they were closed was blocked by a repair tag hanging from a switch above it. That left the reactor dependent on another backup system, a special sort of relief valve. But as luck would have it, the relief valve wasn't working properly that day either. It stuck open when it was supposed to close, and to make matters even worse, a gauge in the control room which should have told the operators that the relief valve wasn't working was itself not working. By the time TMI's engineers realized what was happening, the reactor had come dangerously close to a meltdown.

Here in other words, was a major accident caused by five discrete events. There is no way the engineers in the control room could have known about any of them. No glaring errors or spectacularly bad decisions were made that exacerbated those events. And all the malfunctions--the blocked polisher,the shut valves,the obscured indicator,the faulty relief valve, and the broken gauge---were in themselves so trivial that individually they would have created no more than a nuisance. what caused the accident was the way minor events interacted to create a major problem"

Form your own opinion on this!

Statistics must say the more nuclear plants the more accidents!