what is the difference between urannium and plutonium?

Answer 1

In terms of fissile material, plutonium is friskier than uranium, so would not be good for using in a gun-type weapon. Suspect this may be why Pyongyang wanted a uranium program to supplement their plutonium. The weapon design is easier for breaking into the club.

Answer 2

Uranium is element with atomic number Z =92 . It is radioactive but exits in ores since the period is very long

Plutonium has Z = 94 . It is an artificial element which is produced by nuclear industry

They are both actinides elements with same chemical properties

with my link, it is a periodic table which gives you the properties of all elements