Walrus pups are able to swim at birth and weigh between 100 and 150 pounds. Most are only children (twin births are rare), and they stay with their mothers for two years. Eventually, their small young tusks will grow up to three feet long.
Definition of nuclear for Students. 1  1 : of, relating to, or being a nucleus (as of a cell) 2  2 : of or relating to the nucleus of the atom Fission is a nuclear reaction. 3  3 : produced by a nuclear reaction nuclear energy.  4 : of, relating to, or being a weapon whose destructive power comes from an uncontrolled nuclear reaction.
Nuclear fission is a process in nuclear physics in which the nucleus of an atom splits into two or more smaller nuclei as fission products, and usually some by-product particles. Hence, fission is a form of elemental transmutation. The by-products include free neutrons, photons usually in the form gamma rays, and other nuclear fragments such as beta particles and alpha particles.