I think my main point is that engineers operate in a field that is always going to be subject to pressure, both commercial, political, prestige and so on and that even though the engineering profession in general can be relied upon to do their level best to produce high quality and reliable solutions the various pressures have the ability to push that which is commercially still viable into the realm of danger. The shuttle debacle is an excellent example of how even though everybody worked with the best of intentions this can eventually lead to a disastrous outcome and it is exactly the use of out-of-spec parts for critical applications that you find as the root cause. Once you start doing that the pressure is on to keep doing it right up to the moment that mother nature gives you the kind of wake up call that you really don't want to have. The big trick is simply not to make that first move down the slope.

Nuclear engineers, while possible made of different stuff than your average bridge-and-road engineers are not exempt from such pressures, and examples that prove this abound.