Isotopes of Uranium

Notes

Uranium has no stable isotopes.

Notable Isotopes

232U [140 neutrons]

Abundance: synthetic

Half life: 68.9 years

Decay Energy: 5.414 MeV

Decays to 228Th.

233U [141 neutrons]

Abundance: synthetic

Half life: 159200 years

Decay Energy: 4.909 MeV

Decays to 229Th.

234U [142 neutrons]

Abundance: 0.006%

Half life: 245500 years

Decay Energy: 4.859 MeV

Decays to 230Th.

235U [143 neutrons]

Abundance: 0.72%

Half life: 7.038 x 108 years

Decay Energy: 4.679 MeV

Decays to 231Th.

235U is unique in its ability to cause a rapidly expanding fission chain reaction, i.e., it is fissile. In fact, U-235 is the only fissile isotope found in nature. It was discovered in 1935 by Arthur Jeffrey Dempster . A uranium nucleus that absorbs a neutron splits into two lighter nuclei ; this is called nuclear fission. It releases either two or three neutrons which continue the reaction. In nuclear reactors, the reaction is slowed down by the addition of control rods which are made of elements such as boron, cadmium, and hafnium which can absorb a large number of neutrons. In nuclear bombs, the reaction is uncontrolled and the large amount of energy released creates a nuclear explosion.

236U [144 neutrons]

Abundance: synthetic

Half life: 2.342 x 107 years

Decay Energy: 4.572 MeV

Decays to 232Th.

238U [146 neutrons]

Abundance: 99.275%

Half life: 4.468 x 109 years

Decay Energy: 4.260 MeV

Decays to 234Th.