NUCLEAR FISSION
Nuclear fission * the splitting of large nuclei into smaller fragment nuclei.
There is a small loss in mass after fission has occurred.Einstein’s 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’ neutrons
High speed ‘fission’ fragment
gamma rays
gamma rays
U - 235
Chain reaction * occurs when one fission event causes further fission events .
Fission neutrons cause
further fission
In a nuclear bomb two pieces of pure U 235 or Pu 239
are forced together to exceed the critical mass of 4.5kg.
Sub critical masses lose too many neutrons so the chain reactiondoes not take place
gamma rays
gamma rays
gamma rays
gamma rays
U - 235
Fissionable 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 fission
A PWR REACTOR
a nucleus of U-235 or P-239 splits
U-235
P-239
A
C
B
A
If all the mass in a spoonful of sugar (5g) was converted to energyby Einstein’s 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 Einstein’s 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 Einstein’s 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 Einstein’s 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 Einstein’s 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 Einstein’s 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 Einstein’s 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 Einstein’s 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 Bombs
Sub critical masses
Nuclear Bombs
above critical mass
A PWR REACTOR