Nuclear Fission & Thermonuclear Fusion

What physics words are in the word snake? Niuanupenepkniuraniumumurneumrannibdvivu Mneutoohvvmxabeefajodneutronnndconereelre Emthgyytotyllejbhgiopdncontrolrodhcvuohuihea Hbneafknpcnbbemneafghhchainnloeannfasewp Gieagamamraerareactionbeardednrosnwomano fnfnofguildfordsmnyxalagskhiepwcboihobldndnb

What physics words are in the word snake? Niuanupenepkniuraniumumurneumrannibdvivu Mneutoohvvmxabeefajodneutronnndconereelre Emthgyytotyllejbhgiopdncontrolrodhcvuohuihea Hbneafknpcnbbemneafghhchainnloeannfasewp Gieagamamraerareactionbeardednrosnwomano fnfnofguildforsfissionlagskhiepwcboihobldndnb

How does a nuclear power station work?

krypton Uranium barium

Nuclear Fission Incoming slow neutron

Nuclear Fission Nuclear Fission Incoming slow neutron

Nuclear Fission Nuclear Fission Incoming slow neutron

Nuclear Fission Incoming slow neutron

Nuclear Fission Incoming slow neutron

Nuclear Fission Incoming slow neutron

Nuclear Fission Incoming slow neutron

Nuclear Fission Incoming slow neutron

Nuclear Fission Incoming slow neutron

Nuclear Fission Incoming slow neutron

Nuclear Fission Neutron is absorbed by nucleus

Nuclear Fission Neutron is absorbed by nucleus

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus becomes unstable and starts to oscillate.

Nuclear Fission Nucleus splits! (fissions) into two large pieces and 2 or 3 neutrons

Nuclear Fission Massive release of energy. Particles fly apart

Nuclear Fission Massive release of energy. Particles fly apart

Nuclear Fission Massive release of energy. Particles fly apart

Nuclear Fission Massive release of energy. Particles fly apart

Nuclear Fission Massive release of energy. Particles fly apart

Mass has been turned into energy Mass Before Mass After Mass has been turned into energy

Nuclear reactor What do the control rods do?

Absorb the excess neutrons so a chain reaction does not happen. Control Rods Usually made of Boron Absorb the excess neutrons so a chain reaction does not happen.

Chain Reaction

Chain Reaction

Chain Reaction

Chain Reaction Little bang

Chain Reaction Little bang

Chain Reaction Little bang

Chain Reaction Little bang

Chain Reaction

Chain Reaction Bigger bang

Chain Reaction

Chain Reaction

Chain Reaction

Chain Reaction

Chain Reaction Even bigger bang

Chain Reaction

Chain Reaction

Chain Reaction

Chain Reaction

Chain Reaction

Extremely large bang

After 30 cycles, more than 68 000 billion atoms have been spilt

Nuclear fission Explain the stages in the diagram to the right. 2 1 1. 2. 2 1 Uranium is used to produce heat in a nuclear reactor. This is called ___________ fission. The decay of uranium can be a chain reaction. Finish the diagram of the large scale fission….. A Nuclear bomb Why did it happen?

Nuclear fission Explain the stages in the diagram to the right. 2 1 1. A slow moving neutron collides with Uranium-235 making it unstable. 2. The uranium-235 splits into two daughter nuclei (Krypton and Barium) and releases 3 neutrons. These neutrons may go on to collide and cause the fission of 3 more uranium-235 nuclei. 2 1 Uranium is used to produce heat in a nuclear reactor. This is called nuclear fission. The decay of uranium can be a chain reaction. Finish the diagram of the large scale fission….. A Nuclear bomb Why did it happen? Nuclear fission caused an uncontrolled chain reaction to occur. Massive amounts of energy create high pressure resulting in an explosion.

The first atomic bombing

Little boy-Uranium Hiroshima bomb Type Nuclear weapon Place of origin United States Specifications Weight 9,700 pounds (4,400 kg) Length 120 inches (3.0 m) Diameter 28 inches (710 mm)

Hiroshima bomb It has been estimated that 130 000 to 150 000 persons had died by the end of December 1945. Its design was not tested in advance, unlike the more complex plutonium bomb Fat Man.

Fat man- plutonium core Nagasaki Fat man- plutonium core Type Nuclear weapon Place of origin United States Specifications Weight 10,213 pounds (4,633 kg) Length 10.7 feet (3.3 m) Diameter 5 feet (1.5 m)

Nagasaki An estimated 39 000 people were killed outright by the bombing at Nagasaki, and a further 25 000 were injured.

Nagasaki 2 days before the bomb

Nagasaki 3 days after the bomb

Nagasaki 11 miles high

Nuclear disaster @ Chernobyl

Questions 1.Explain how the chain reaction is controlled in a nuclear reactor. 2. Assuming all three neutrons go on to spilt other atoms, how many atoms would have been split on the: 3rd cycle 20th cycle 15th cycle 3. Use the diagram to show how a nuclear power station works in terms of nuclear fission and the stages that follow.

Questions 1.Explain how the chain reaction is controlled in a nuclear reactor. 2. Assuming all three neutrons go on to spilt other atoms, how many atoms would have been split on the: 3rd cycle 20th cycle 15th cycle 3. Use the diagram to show how a nuclear power station works in terms of nuclear fission and the stages that follow. 9 1 162 261 467 4 782 969

Diagram

Sort the statements into two piles You should know the key points about fission now. Collect the fusion statements by elimination. Nuclear Fission Vs Thermonuclear Fusion

Nuclear Fission Thermonuclear Fusion Uranium 238 is used in a nuclear reactor to generate heat energy. This happens naturally in stars. A chain reaction can occur if this reaction is not controlled. An extremely high temperature and high pressure is needed for this reaction to take place. Control rods are used to control this type of nuclear reaction. They absorb the excess neutrons. Fusing together of Hydrogen nuclei resulting in the formation of Helium. The splitting of radioisotope nuclei. This nuclear reaction, as well as fission, takes place in a Hydrogen Bomb. The bombs dropped in Hiroshima and Nagasaki during world war II ,called Fat man and little boy, involved this type of nuclear reaction. Producing this reaction on Earth is very difficult due to the conditions needed for it to happen. Involves the firing of a neutron which makes the nucleus of uranium unstable. This method could be used to generate power in the future . It could replace conventional power stations. After 12 cycles, assuming that three neutrons are released per cycle, 531 441 atoms will have been split. This method releases more energy. (Assume the same amount of atomic matter is used)

Fusion Stars are basically natural fusion reactors! Their size, temperature and internal pressure mean that the nuclear fusion of hydrogen occurs forming helium and releasing vast amounts of energy.

What is Thermonuclear fusion? Nuclear fusion occurs when nuclei are stuck (or fused) together. Fusion is different to fission. In fusion two small nuclei join to make a single heavier nucleus. The process generates heat energy (just like fission). Nuclear fusion is the process by which energy is released in stars. The products of nuclear fusion are not radioactive.

Typical thermonuclear reaction Hydrogen-1 Fuses with Hydrogen-2 to make Helium-3. Hydrogen-1 Hydrogen-2 (Deuterium)

Deuterium Tritium Hydrogen Isotopes You don’t need to know this but if you’re interested! MeV=Mega electron Volt 1 eV is defined to be the energy required to move an electron through a potential difference of 1 Volt.

Isn’t it amazing to think that all the matter on Earth, including you, was once created in stars and then involved in a supernova explosion. The smallest stars only convert hydrogen to helium. Medium sized stars like our Sun convert hydrogen to helium and then, later in their life, nuclear fusion of helium takes place to form oxygen and carbon. Massive stars, later in their life, fuse nuclei to produce heavier elements. Elements larger than iron are formed when large stars die and explode in a supernova.

The Hydrogen Bomb Fission of uranium will create the heat needed for the fusion of Hydrogen. Stage 1: Fission of uranium or plutonium (Learnt last lesson) Stage 2: Fusion of Hydrogen to Helium Stage 3: Already depleted uranium will undergo fission due to heat, pressure and energy of the bomb (Not all bombs use this stage)

Tsar Bomba (Big Ivan) Largest detonated hydrogen Bomb test. Russia. Test drop in the Arctic sea. 97% of energy came from Fusion.

Task Read the information provided. Underline any key points. Highlight any advantages of using Thermonuclear fusion to generate power in green and the disadvantages in red.

Questions Explain why nuclear fusion is difficult to achieve on earth (4) 2. Has cold fusion been achieved? (2) 3. Explain how nuclear fusion may be used to generate power in the future and discuss the advantages and disadvantages surrounding this (6)

Solution Explain why nuclear fusion is difficult to achieve on earth (4) Nuclei are positive and will normally repel (1) Difficult to get extreme pressure (1) Extreme temperature (1) To fuse the hydrogen Nuclei together (1)

2. Has cold fusion been achieved? (2) Solution 2. Has cold fusion been achieved? (2) No Scientists claimed to achieve cold fusion This could not be proved despite several attempts by scientists to re-create the fusion following the same method.

Solution 3. Explain how nuclear fusion may be used to generate power in the future and discuss the advantages and disadvantages surrounding this (6) Fusion is the fusing together of Hydrogen nuclei to form Helium and release huge amounts of energy Extreme pressure and heat in stars provide the right conditions for this to happen Any two advantages and disadvantages

Fusion and Fission Remember the difference between fission and fusion: Fission is the splitting of atomic nuclei to form smaller nuclei and energy. Fusion is the joining (or fusing) of two nuclei to form a larger nucleus and energy.