Nuclear Energy Fission and Fusion. Nuclear Energy. The nucleus of an atom is the source of nuclear energy . . Nuclear Energy. Fission - when the nucleus splits & nuclear energy is released. (Heat and Light energy)
Nuclear EnergyFission and Fusion
3 2 4
1 H + 1 H 2 He + n0 + ENERGY
The sun’s energy is produced from a nuclear fusion reaction
2 hydrogen nuclei fuse to form 1 helium nucleus, a neutron, & ENERGY
– Deuterium - inexhaustible supply from sea water (1 part/ 6,500 H20)
– Tritium - produced from Lithium, thousands of years supply
– No meltdown possible
– Large uncontrolled release of energy impossible
– Reaction product is Helium
– Careful material selection should minimize waste caused by neutron activation
Fusion is the release of energy by combining two light nuclei such as deuterium and tritium
Fission is the release of energy by splitting heavy nuclei such as Uranium-235 and Plutonium-239
Controlled Fission Chain Reaction
There are two main confinement approaches:
The energy from the reaction drives a steam cycle to produce electricity
Nuclear Power Plant
Natural (radioactive) decay (fission)
235U (Uranium isotope with 92 protons and 143 neutrons) works!! Releases 2.5 neutrons when fissioning.
238U (Uranium isotope with 92 protons and 146 neutrons), which naturally occurs more abundantly (99.28%) does not work.
For bomb: Need to enrich 235U (very difficult, fortunately).
Assembly of supercritical mass
(to initiate 235U bomb)
Hiroshima, Aug. 6, 1945
Two-thirds of Hiroshima was destroyed. Within three miles of the explosion, 60,000 of the 90,000 buildings were demolished. Clay roof tiles had melted together. Shadows had imprinted on buildings and other hard surfaces. Metal and stone had melted.
Hiroshima's population has been estimated at 350,000; approximately 70,000 died immediately from the explosion and another 70,000 died from radiation within five years.
At the time this photo was made, smoke billowed 20,000 feet above Hiroshima while smoke from the burst of the first atomic bomb had spread over 10,000 feet on the target at the base of the rising column.
239Pu (Plutonium) bomb
Supercritical mass (density) of Plutonium core is achieved when explosion crushes 239Pu core.
Nagasaki, Aug. 9, 1945
Approximately 40 percent of Nagasaki was destroyed. Though this atomic bomb was considered much stronger than the one exploded over Hiroshima, the terrain of Nagasaki prevented the bomb to do as much damage. Yet the decimation was still enormous. With a population of 270,000, approximately 70,000 people died by the end of the year.
A dense column of smoke rises more than 60,000 feet into the air over the Japanese port of Nagasaki, the result of an atomic bomb, the second ever used in warfare, dropped on the industrial center August 8, 1945, from a U.S. B-29 Superfortress.