By comparison , the first plutonium core nuclear device tested by the United States ( Trinity test ) had a yield of 20 kilotons of TNT , and the first nuclear device detonated by India in 1974 , though of primitive design , had a yield in the region of 8 kilotons of TNT . If the North Korean nuclear test is less than even a kiloton in yield , it would be a historically small inaugural nuclear test . Even if it were as many as the reported intentional yield of 4 kt it would be the smallest nuclear test ever conducted by a state as a first test . Some advanced nuclear powers have produced very small tactical nuclear weapons in the low-kiloton range , but their development is far more technologically challenging than that of weapons in the 15 – 20 kiloton range , requiring advanced weapons materials and core geometries
Trinity test
Trinity (nuclear test)
2006 North Korean nuclear test