# nuclear fission

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NUCLEAR FISSION. gamma rays. gamma rays. High speed ‘fission’ fragment. Nuclear fission * the splitting of large nuclei into smaller fragment nuclei. High speed ‘fission’ neutrons. U - 235. There is a small loss in mass after fission has occurred. - PowerPoint PPT Presentation

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• NUCLEAR FISSIONNuclear fission * the splitting of large nuclei into smaller fragment nuclei.There is a small loss in mass after fission has occurred.Einsteins equation: E = mc2 shows how much energy is released. c = speed of light 300,000,000 m/s and c2 = 9 x 10 16 !! High speed fission neutronsHigh speed fission fragment

U - 235

• Chain reaction * occurs when one fission event causes further fission events .Fission neutrons cause further fissionIn a nuclear bomb two pieces of pure U 235 or Pu 239are forced together to exceed the critical mass of 4.5kg.

Sub critical masses lose too many neutrons so the chain reactiondoes not take place U - 235Fissionable isotopes: Only Uranium -235 is fissionable in the nuclear reactor. Plutonium -239 is also fissionable and is created from the more common Uranium 238. ( 99% of natural uranium is U 238.)

• Fuel rods with enriched Uhaving 3% U 235 instead of less than 1%( the rest is U 238)A moderator slows down the fast moving neutrons to allow successful collisions with U235 nuclei Boron/steel control rods absorb surplus neutrons.

Their depth allows one neutron per fission to produce one further fissionA PWR REACTOR

• a nucleus of U-235 or P-239 splitsU-235P-239ACBA

• If all the mass in a spoonful of sugar (5g) was converted to energyby Einsteins equation: E = mc2

c = speed of light 300,000,000 m/s and c2 = 9 x 10 16

Q1. How much energy is released?Q2. If the UK needs 50GW of power and power stations are 30% efficient , how long could a spoonful of sugar keep the UK supplied with electricity? E = m x c2 E = 5 x 10 -3 x 9 x 10 16 E = 45 x 10 13 J

• If all the mass in a spoonful of sugar (5g) was converted to energyby Einsteins equation: E = mc2

c = speed of light 300,000,000 m/s and c2 = 9 x 10 16

Q1. How much energy is released?Q2. If the UK needs 50GW of power and power stations are 30% efficient , how long could a spoonful of sugar keep the UK supplied with electricity? E = m x c2 E = 5 x 10 -3 x 9 x 10 16 E = 45 x 10 13 J

• If all the mass in a spoonful of sugar (5g) was converted to energyby Einsteins equation: E = mc2

c = speed of light 300,000,000 m/s and c2 = 9 x 10 16

Q1. How much energy is released?Q2. If the UK needs 50GW of power and power stations are 30% efficient , how long could a spoonful of sugar keep the UK supplied with electricity? E = m x c2 E = 5 x 10 -3 x 9 x 10 16 E = 45 x 10 13 J % Efficiency = useful power x 100% total power

total power = 50 x 10 9 x 100% 30%

= 167 x 10 9 W

• If all the mass in a spoonful of sugar (5g) was converted to energyby Einsteins equation: E = mc2

c = speed of light 300,000,000 m/s and c2 = 9 x 10 16

Q1. How much energy is released?Q2. If the UK needs 50GW of power and power stations are 30% efficient , how long could a spoonful of sugar keep the UK supplied with electricity? E = m x c2 E = 5 x 10 -3 x 9 x 10 16 E = 45 x 10 13 J Power = Energy transferred time

time (sec) = Energy transferred = 45 x 10 13 J = 0.27 x 10 4 sec Power 167 x 10 9 W = 45 Mins

% Efficiency = useful power x 100% total power

total power = 50 x 10 9 x 100% 30%

= 167 x 10 9 W

• If all the mass in a spoonful of sugar (5g) was converted to energyby Einsteins equation: E = mc2

c = speed of light 300,000,000 m/s and c2 = 9 x 10 16

Q1. How much energy is released?Q2. If the UK needs 50GW of power and power stations are 30% efficient , how long could a spoonful of sugar keep the UK supplied with electricity? E = m x c2 E = 5 x 10 -3 x 9 x 10 16 E = 45 x 10 13 J % Efficiency = useful power x 100% total power

total power = 50 x 10 9 x 100% 30%

= 167 x 10 9 W

• If all the mass in a spoonful of sugar (5g) was converted to energyby Einsteins equation: E = mc2

c = speed of light 300,000,000 m/s and c2 = 9 x 10 16

Q1. How much energy is released?Q2. If the UK needs 50GW of power and power stations are 30% efficient , how long could a spoonful of sugar keep the UK supplied with electricity? E = m x c2 E = 5 x 10 -3 x 9 x 10 16 E = 45 x 10 13 J Power = Energy transferred time

time (sec) = Energy transferred = 45 x 10 13 J = 0.27 x 10 4 sec Power 167 x 10 9 W = 45 Mins

% Efficiency = useful power x 100% total power

total power = 50 x 10 9 x 100% 30%

= 167 x 10 9 W

• If all the mass in a spoonful of sugar (5g) was converted to energyby Einsteins equation: E = mc2

c = speed of light 300,000,000 m/s and c2 = 9 x 10 16

Q1. How much energy is released?Q2. If the UK needs 50GW of power and power stations are 30% efficient , how long could a spoonful of sugar keep the UK supplied with electricity? E = m x c2 E = 5 x 10 -3 x 9 x 10 16 E = 45 x 10 13 J Power = Energy transferred time

time (sec) = Energy transferred = 45 x 10 13 J = 0.27 x 10 4 sec Power 167 x 10 9 W = 45 Mins

% Efficiency = useful power x 100% total power

total power = 50 x 10 9 x 100% 30%

= 167 x 10 9 W

• If all the mass in a spoonful of sugar (5g) was converted to energyby Einsteins equation: E = mc2

c = speed of light 300,000,000 m/s and c2 = 9 x 10 16

Q1. How much energy is released?Q2. If the UK needs 50GW of power and power stations are 30% efficient , how long could a spoonful of sugar keep the UK supplied with electricity? E = m x c2 E = 5 x 10 -3 x 9 x 10 16 E = 45 x 10 13 J Power = Energy transferred time

time (sec) = Energy transferred = 45 x 10 13 J = 0.27 x 10 4 sec Power 167 x 10 9 W = 45 Minsso 1Kg bag of sugar could keep the national grid running for 6 days!% Efficiency = useful power x 100% total power

total power = 50 x 10 9 x 100% 30%

= 167 x 10 9 W

• Nuclear BombsSub critical masses

• Nuclear Bombsabove critical mass

• A PWR REACTOR

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