Problems with nuclear fission

Answer 1

Nuclear reactors are provided with safety systems that shut the reactor down quickly if instruments detect any out of the ordinary behaviour. In the case of a nuclear weapon, it's a "dud" complete with the radioactive mess associated with a failed shot. In the case of a nuclear reactor, those who are operating the plant perform their duties in shifts in the control room. This work area is full of the control and monitoring equipment necessary to the task. The operators keep track of what is going on in the systems and subsystems of the plant, and they can operate the reactor from this location. Those operators are trained at length to do what needs to be done to keep things running, and also to make the "right moves" when thing go sideways. There are a number of automatic systems that will shut the plant down under certain conditions, but there are a number of other excursions that may occur where operator action is all that prevents things from getting really messed up. There are situations where problems can occur that are insufficient to "trip" or "trigger" emergency cooling or even automatic shut down systems. It is in these "twilight" situations that operators must recognize a developing problem and step in with the correct action to cut off something serious. And we've seen the failure of operators to do that (recognize a problem and take proper corrective action) in the case of Three Mile Island.

Answer 2

The problems of using nuclear fission as a human power source are the issues of radioactive wastes, and that the fact that the materials the energy is produced form is difficult to obtain.