duress at this plant meets those characteristics. and so i -- >> split second decisions like what, edwin? >> well, when -- in the control room, and something happens, you know, there is a transient you get, indications of something that's going wrong, and you have to diagnose it and know how to fix it. that isn't always an easy thing. it really does take a great deal of skill. operators are trained on simulators to cope with these types of accidents but fatigue and inattention have been big problems in the past in control rooms. >> i've got to ask you this before i let you go. the u.s. ambassador to the u.n. says russian forces are 20 miles from closing in on ukraine's second largest nuclear facility. are you concerned about another potentially disastrous situation there? >> well, there is no reason to