So you are saying that because the "2012 event" was caused by a mistake rather than a by a malicious action by the insider. So you are saying that there is no legitimate fear because the motive of the insider was probably pure. However, this is contradicted by the paper which said:
An internal investigation found “evidence of potential tampering as the cause of the
abnormal condition,” as the company reported to the Nuclear Regulatory Commission (NRC).
Another way to look at it is this: From what I read about the incident, a fluid was put into the lubrication system of the backup diesel generator which would have caused the generator to quickly overheat and fail, if it were ever to be run (like in an emergency, for example). Do you realize that this is precisely what caused the Fukushima nuclear disaster in Japan in 2011?
http://en.wikipedia.org/wiki/F... The cooling system for the reactors failed because they didn't have power from any diesel generator, and this (in part) caused the meltdown.
It sounds wise for nuclear industry to remain vigilant to the possibility of insider threat.