Nuclear Steam Generators

The nucleus of heavy elements like U-233, U-235 and Pu-239 has the ability to capture and absorb neutrons, whereupon it gets converted to a compound nucleus. Sometimes this compound nucleus is highly unstable undergoing spontaneous fragmentation into several approximately equal lighter nuclei plus two or three neutrons. This process is called nuclear fission and is accompanied by enormous amount of heat liberation (Fig. 15.1).