What force exists all around us and does not require any electrical power to work? How can this force be used in the design of a reactor emergency cooling system?

What force exists all around us and does not require any electrical  power to work?  How can this force be used in the design of a reactor  emergency cooling system? 

 
Nuclear energy is used as an alternative to fossil fuels. Nuclear  power is created by controlled nuclear reactions. The nucleus of an atom  contains energy. In a nuclear power plant, the energy contained in a  radioactive atom such as uranium (U) is released by splitting or  breaking down the nuclei. This process is called nuclear fission, and it  creates large amounts of heat.
In nuclear power plants, the heat given off by the nuclear reaction  is used to change water into steam. Similar to the other power  generation systems covered so far, the steam passes through a turbine,  rotating the turbine at high speeds, which in turn moves the magnetic  field over the coils of the generator, producing electrical current.  After the steam leaves the turbine it is usually condensed back to water  and pumped back into the nuclear-fueled boiler for the process to begin  again