Protons for Breakfast
Week 6
Do we need nuclear power?
In the event of an alarm sounding…
Nuclear Power
The UK Energy Scene
Nuclear Power
The UK Context
• How is electricity generated?
• How much electricity does Britain need and where does it come from?
• Nuclear Power Stations are due for closure
– Energy Gap?
• How to replace the lost generating capacity?
– Reduce demand, Wind Power, Tidal Barrage, Solar Power?
• Nuclear Power?
– Radioactivity & Nuclear Fission
– Pros and Cons
Tonight’s Talk
Electricity generation in the UK
• How is electricity generated?
• How much electricity does Britain need and where does it come from?
• Nuclear Power Stations are due for closure
• How to replace the lost generating capacity?
– Reduce demand, Wind Power, Tidal Barrage, Solar Power?
• Nuclear Power?
– Radioactivity & Nuclear Fission
– Pros and Cons
Does Britian need nuclear power?
Jonathan Pearce
Laurie Winkless
Andrew Hanson
Lindsay Chapman
Arzu Arinc
Lloyd England
Averil Horton
Mateusz Szymanski
Bufa Zhang
Matthew Tedaldi
Clive Scoggins
Neelaksh Sadhoo
Daniel Gittings
Paul Carroll
Davide Di Maio
Peter Quested
Deborah Lea
Peter Woolliams
Eleanor Bakhshandeiar Rainer Winkler
Emma Woolliams
Richard Gilham
Gianluca Memoli
Robert Goddard
Jacquie Elkin
Robin Underwood
James Miall
Ruth Montgomery
Jeff Flowers
Sharmila Hanson
Jenny Wilkinson
Stephanie Bell
Jian Wang
Thomas Korrison
Joanna Lee
John Makepeace
John Mountford
Helpers
Experts
Martin Milton
Paul Quincy
Nigel Fox
Andrew Gregory
Andrew Beardmore
Bob Clarke
Kevin Lees
Alan DuSautoy
Alan Turnbull
Nigel Jennett
John Makepeace
Simon Jerome
Electricity
Eeeee - lec- tric-ity
Where does it come from?
Tonight’s Talk
How is electricity generated?
How is electricity generated? (1)
Type of
station
Electricity
made by…
What makes coil
turn?
Energy
Source
Coal
Coil turning in a
magnetic field
Turbine driven by
hot steam
Chemical
C + O2  CO2
Gas
Coil turning in a
magnetic field
Turbines driven by
hot gas and steam
Chemical
CH4 + 2O2 
CO2 + 2H20
Nuclear
Coil turning in a
magnetic field
Turbine driven by
hot steam
Nuclear Fission
U + n ???
Stellar
Wind/Wave
Coil turning in a
magnetic field
Turbine driven by
air or water
Nuclear Fusion
4H  He
Solar
Mamod
Coil turning in a
magnetic field
Pistons driven by
steam
Chemical
C + O2  CO2
?
Ultimate Source
Solar
Solar
Mamod
While the station powers up…
• Please take 10 minutes to fill out the feedback forms.
• These forms are important
• They help everyone involved in the course assess
whether it has been successful, and decide what to
change and what to keep the same
Ticking the boxes is important, but
your comments are especially valuable.
How much electricity do we need?
Electricity Generation in UK
Daily variations in 2001/2002
gigawatt
(GW)
1 gigawatt
(GW)
9 W9 W
billion
watts
billion
watts
=10=10
= 1000000000
W
=10 Million
100 W light bulbs
=10 Million
Light
bulbs
Roughly speaking
1 large
power
station
60
Actual National Grid Demand (GW)
Actual National Grid Demand (GW)
60
50
Typical Summer Demand
40
30
20
Minimum Summer Demand
10
Sleep
0
0.00
6.00
Work
12.00
18.00
Time of day
24.00
Maximum Winter Demand
50
40
30
Typical Winter Demand
20
10
Sleep
0
0.00
6.00
Work
12.00
18.00
Time of day
24.00
Electricity Demand 2001-2009
Mmmm. Looks near to
60 GW peak demand!
Electricity Generation in UK
Daily variations in 2001/2002
1 gigawatt (GW)
billion watts =109 W
=10 Million 100 W light bulbs
Roughly speaking 1 large power station
Required
generating
capacity (GW)
Summer
Winter
Peak
45
60
Base
25
30
Daily MaximumDaily Minimum
30
Energy Consumption Right Now!
How do we meet this demand?
Electricity Generation in UK
Typical Winter Demand
Figure 2.5(b) - Typical Winter Demand (Thursday 6th December 2001)
Thursday 6th December 2001
Power
Other
60
(GW)
Imports
50
40
40
MW
50
30
30
20
20
Large Coal
Gas (Combined Cycle)
10
10
Nuclear
Time
Time of Day
Nuclear
CCGTs
Outside Sources
Large Coal
Other Coal
Oil
Pumped Storage
Other
23:00
22:00
21:00
18:00
20:00
19:00
18:00
17:00
16:00
15:00
12:00
14:00
13:00
12:00
11:00
10:00
09:00
6:00
08:00
07:00
06:00
05:00
04:00
03:00
0:00
02:00
01:00
0
00:00
0
24:00
Electricity Generation in UK
Data from 2004
Wind/Biomass/Landfill Gas
3.5%
Hydroelectric
1%
Imports
2.5%
Coal
33%
Nuclear
19%
Gas
40%
Oil
1%
Current UK Nuclear Capacity
History and Future
• Decline could be faster
• Energy Gap?
Installed Nuclear Capacity (GWe)
14
12
10
8
Total
History
Magnox
AGR
Future
SGHWR
6
PFR
PWR
4
2
0
1950
1960
1970
1980
1990
2000
Year
2010
2020
2030
2040
2050
Electricity Generation in UK
2020
• Nuclear will decline
• Renewables will increase
– but by how much?
• No shortage of coal and
gas
– See BP Energy Review
– Cost?
– Security of supply?
Wind/Biomass/Landfill Gas
3.5%
Hydroelectric
1%
??????????
??????????
Nuclear
??????????
Gas
40%
http://www.bp.com/productlanding.do?categoryId=6929&contentId=7044622
Imports
2.5%
Coal
33%
Oil
1%
Alternatives?
Renewable 60
50
Is it possible to:
• Reduce Gas and Coal generation
• Increase Renewables
• Avoid replacing Nuclear Power
stations
Gas
&
Coal
40
30
20
Can we reduce demand?
10
Nuclear
What to do?
Reduce Demand
• My family’s electricity usage for the last four years
• Can we make people and businesses use
less?electricity?
• Price
• Rationing
Annualised Electricity Consumption
10000
2005
2006
2007
2008
9000
8000
7000
kWh
6000
5000
4000
3000
2000
1000
2000 kWh
20% reduction
£260 a year
Universal use of CF light bulbs will
eliminate the need for
1 large power station
Electricity Usage in UK 2004
Lighting
• Several easy wins
Commercial
18%
Losses
8%
Domestic
29%
Fuel
Industries
8%
Public
Adminsitration
5%
Transport 2% Agriculture 1%
Industry
29%
Alternatives?
60
Most people would think
this is wildly optimistic!
50
So reducing demand could help.
40
What can wind provide?
30
20
10
Wind Power (1)
UK Wind in 2007
• UK has some of the best
sites in Europe
• Currently
– 154 Projects
– 1900 Turbines
– 2.293 GW
• Plus
1.3 GW under construction
4.6 GW planning approved
9.8 GW seeking approval
18 GW in a few years time
Wind Power
Could we get 10% (5.3 GW) of
electricity from wind?
•Wind has problems of
–availability
–variability
• Build 5000 of the largest wind turbines
13 GW
• On average generates only 5.3 GW
• Sometimes more: Sometimes less!
• Can’t control when!
• Retain 3 GW of coal fired
capacity as ‘backup’
5.3 GW
3 GW
Alternatives?
60
Very ambitious, but
achievable…
50
WIND
40
So wind can provide a lot of power,
but we can’t control when it is generated
30
Could we store some of the power?
20
10
Wind Power
The Grid
• Electricity needs to be generated at
exactly the time it is needed.
• Storage is possible, but difficult:
• Variability limits likely maximum
wind contribution to about…
– 10%? Yes
– 20%? Arguably
– 30%? Unlikely
Photo Credit Spencer Jarvis
Electricity Generation in UK
Pumped Storage
0 to 1.3 GW
in 12 seconds
1.5
Pumped Storage (GW)
Energy Use
1.0
0.5
0.0
-0.5
-1.0
Energy Storage
-1.5
0
6
12
Time of Day
18
24
Other Alternatives?
60
50
So reducing demand can help.
40
And wind and stored energy could help too 30
What about solar electricity?
20
10
WIND
WIND
&
STOR
Solar Photo Voltaic
Step 1
• Put this on your roof
• 9 m2
• Twickenham
Solar Photo Voltaic
Step 2
• Put these in your
house
Daily generation rate
Solar Photo Voltaic
Hey presto!
10.00
kWh/day
8.00
6.00
4.00
2.00
62
58
54
50
46
42
38
34
30
26
22
18
14
10
0.00
w eek #
• Average: 3.5 kWh/day (1277.5 kWh/year)
• Saving: 3.5 x 13 pence per kWh = 46 p/day (£166 / year)
• Cost in: 2005: £9000
• Return on investment: 1.8 %
Other Alternatives?
60
Mainly in Summer…
50
WIND
WIND
&
STOR
40
So reducing demand can help.
And wind and stored energy could help too.
Even solar energy can help
SUN
30
20
10
Severn Tidal Barrage
Could generate
10% of UK
demand
5 GW
£15B
Nuclear Fusion
Nuclear Fusion
Nuclear Fusion
What is it?
100,000,000
1,000,000
10,000 ºC
deuterium
nucleus
neutron
proton
Fusion
JET
http://www.jet.efda.org/
ITER
http://www.iter.org/default.aspx
Probability of Success by 2025
????25%????
Probability of Engineering Feasibility by 2100
???? 5%????
Summary
Mmm…Every one of
these figures looks
optimistic…
Action
Reducing demand
Effect (GW)
50
10
tidal barrage or lagoons
10
Solar energy
3
?
WIND
WIND
&
STOR
40
SUN
10
wind and stored energy
And there are many other
possibilities…
60
30
20
10
TIDE
Nuclear Power
The UK Context
Carbon Crunch
60
50
Method of
generation
Kilograms of CO2
emitted for every 1
kWhe supplied:
Coal
1
Gas (CCGT)
0.5
Wind
0.01
Tide
0.01
Nuclear
0.01
WIND
WIND
&
STOR
40
SUN
30
20
10
TIDE
Summary
60
50
• 11 GW of CO2-free generating
capacity will be retiring in the
next 17 years
• Even replacing it will not
reduce CO2 emissions
WIND
WIND
&
STOR
40
SUN
30
20
So let’s find out about nuclear power! 10
TIDE
To understand nuclear power
and how it works
we first need to understand about
Radioactivity
Some radioactive things (10)
Let’s look at some radioactive things…
Detectors
Cloud Chamber
Supermarket Radioactivity
Remember this…
Electricity
‘Nuclear’ refers
to the nucleus
of atoms
Electromagnetic
waves
Atoms
Heat
Diameter of
the Earth
Powers of Ten
Nuclear Power
Distance to
the Sun
Microbes
10-18 10-12
Human
Relationships
10-6
Very
Very
Small 10-15 10-9
100
106
10-3 103
1012 1018 1024 1030 1036
109
1015 1021 1027 1033
Nuclei
of atoms Atoms &
molecules
Tallest Mountain
Very
Very
Large
The issues surrounding
nuclear power involve
physical processes with
length scales spanning 25
powers of 10!
How are atoms made?
Electrical Repulsion
proton
Interact by the short range
‘strong’ force – not electrical
How are atoms made?
What is Radioactivity(2)…
• Normally nuclei act as heavy pointlike centres for atoms
• More than 99.9% of the mass of
every atom is made of nuclear
matter
• More than 99.9% of the mass of
your breakfast is made of nuclear
matter
Nucleus
What is Radioactivity(3)…
• The number of protons (+) in
the nucleus determines the
number of electrons required
to make the atom neutral
• This determines the chemical
and physical properties of the
atom
• But the number of neutrons
in a nucleus can vary
What is Radioactivity(4)
Example 39K, 40K and 41K
Same number of protons
Different numbers of neutrons
• Potassium is 2.4% of the Earth’s crust
• Natural potassium (symbol K) has three isotopes
39K
40K
41K
19 protons
20 neutrons
20 + 19 = 39
19 protons
21 neutrons
21 + 19 = 40
19 protons
22 neutrons
22 + 19 = 41
93.3%
0.01%
Radioactive
6.7%
What is Radioactivity(6)…
Three types of radioactivity
• Named with the Greek a, b, c
a alpha, b beta, g gamma
• Nuclei with a ‘balanced’ number of protons and neutrons are stable
Isotopes with
too many protons
Isotopes with
too many neutrons
Alpha decay
Beta decay
Emission of fast moving
helium nucleus
Emission of fast moving
electron
And gamma radiation
And gamma radiation
What is Radioactivity(8)
Alpha (a) Decay
Nucleus with too
many protons
Alpha
particle
gamma ray
Charge oscillations
in nucleus
What is Radioactivity(8)
Beta (b) Decay
Nucleus with too
many neutrons
Beta
particle
gamma ray
Charge oscillations
in nucleus
Radioactivity
What are the health risks
of ionising radiation?
Radioactive health risks
Introduction
• Radioactive emissions a alpha, b beta, g gamma
• If they pass living cells, they interact electrically and cause
damage.
– Cells are killed
– Can cause mutations and cancer
– Very bad for you
• Fortunately we have evolved in a radioactive world
Radioactive health risks
Measurement units
Many ways of measuring radioactive dose
• Optimal measure for effect on human health is the
Sievert
Radioactive health risks
Annual average UK dose
• Average annual dose to the UK
population from all sources
• Average 0.0026 Sieverts
• Average 2.6 milliSieverts
• About 7 microSieverts /day
Source
Dose (mSv)
Natural
Cosmic
0.26
Gamma rays
0.35
Internal
0.3
Radon
1.3
Artificial
Medical
0.37
Occupational
0.007
Fallout
0.005
Products
0.0004
Discharges
0.0002
Total
2.6
Radioactive health risks
Sources
From the sky
About 100,000 cosmic ray
neutrons and 400,000
secondary cosmic rays
penetrate the average
individual every hour
From food
About 15 million
potassium 40 atoms and
7000 natural uranium
atoms disintegrate inside
us each hour
From the air
About 30,000 atoms
disintegrate each hour in
our lungs and give of
alpha, beta, and gamma
radiation
From soil and building materials
Over 200 million gamma rays pass through the
average individual each hour
What is Nuclear Power?
Nuclear Power
How does it work?
Nuclear Fission (1)
‘Fission means splitting’
• Some heavy nuclei can
be induced to fission i.e.
split in two by the addition
of a single neutron
• Nuclear fragments move
very fast. As they interact
with nearby atoms they
cause tremendous
heating
One more ‘wafer thin’ neutron, Sir?
Nuclear Fission (2)
Uranium
• Uranium has two common isotopes 238U and 235U
– Uranium has 92 protons
– The 238 or 235 is the total number of protons and neutrons
238U
235U
neutrons
238 – 92 = 146
235 – 92 = 143
natural
uranium.
99.3%
0.7%
Fissile?
No
Yes
Nuclear Fission (3)
Uranium Fission
•
235U
+ n >>> 236U + n
• After a short while
•
236U
>>> fragments + 3 n
Nuclear Fission (4)
Chain reaction
•
235U
+ n >>> 236U >>> Fragments + 3n
Nuclear Fission (5)
Chain reaction
• Each fission produces 3 extra neutrons on average
– If more than one neutron produces an additional fission
• The rate of fission increases
• If uncontrolled leads to a nuclear explosion
– If less than one neutron produces an additional fission
• Then the rate of fission decreases
• Nuclear reactions will die out
– If exactly one neutron produces an additional fission
• Sustainable nuclear reaction
Nuclear Power Stations
UK Nuclear Energy update
AREVA and
Electricité de
France's (EDF)
European
Pressurized Reactor
(EPR)
Westinghouse
Electric Company's
(WEC) AP1000
pressurized water
reactor (PWR)
Westinghouse Link
What is Nuclear Power?
Nuclear Positives
Nuclear Power
The UK Context
Nuclear Fission (6)
• 1 kg natural uranium has a volume of 50 cm3
– Produces 40 thousand kWh
– Equivalent to 16 tons of coal
• Nuclear energy is cleaner than coal
– Lower radioactive emissions
– Much less radioactive waste
• Conventional Power Stations
– Cheaper than nuclear because they don’t pay to clean up their
waste (CO2)
• Reliability
– One fifth of UK electricity supply for last 30 years
What is Nuclear Power?
Nuclear Negatives
Nuclear Power
The UK Context
Nuclear Power
The UK Context
Catastrophic Explosion
Chernobyl
• 26 April 1986
• 31 dead Immediately
• Ultimate death toll
– 100?
– 15,000?
Chernobyl
Effect on UK
Fall out from
atmospheric
atomic weapons
testing
Total radiation
dose was 20
times less than
the dose from
Annual
the atmospheric dose
bomb tests from (micro
Sieverts)
1945 to 1963.
Chernobyl
1951
Year
1988
Nuclear Power
The UK Context
Nuclear Fission (4)
Chain reaction
•
235U
+ n >>> 236U >>> Fragments + 3n
These fragments
are intensely
radioactive
Waste (4)
Carbon versus Nuclear
Waste
Cost
Worldwide Physical
Mass
Manageable
Radioactive
Waste
Carbon Waste
(CO2)
Large, but
calculable
Incalculable
<1 million tonnes >30 billion tonnes
cumulative total
per year
Probably
Probably not
Nuclear Power
The UK Context
Nuclear Fission (6)
Chain reaction
• Nuclear phenomena has
always been associated
with great hopes and great
fears.
• Chicago
• 3:25 P.M. December 2,
1942
• Nuclear Age began
• Gain = 1.0006
Nuclear Fission (6)
Hopes
Arthur Compton
• One of the things that I shall not forget is the expressions
on the faces of some of the men. There was Fermi's face—
one saw in him no sign of elation. The experiment had
worked just as he had expected and that was that. But I
remember best of all the face of Crawford Greenewalt. His
eyes were shining. He had seen a miracle, and a miracle it
was indeed. The dawn of a new age. As we walked back
across the campus, he talked of his vision: endless
supplies of power to turn the wheels of industry, new
research techniques that would enrich the life of man, vast
new possibilities yet hidden.
Nuclear Fission (6)
Fears
Leo Szillard
• There was a crowd there and when it dispersed, Fermi and I stayed
there alone. Enrico Fermi and I remained. I shook hands with Fermi
and I said that I thought this day would go down as a black day in the
history of mankind.
• I was quite aware of the dangers. Not because I am so wise but
because I have read a book written by H. G. Wells called The World
Set Free. He wrote this before the First World War and described in it
the development of atomic bombs, and the war fought by atomic
bombs. So I was aware of these things.
• But I was also aware of the fact that something had to be done if the
Germans get the bomb before we have it. They had knowledge. They
had the people to do it and would have forced us to surrender if we
didn't have bombs also.
• We had no choice, or we thought we had no choice.
Nuclear Power
The UK Context
Nuclear terrorism (1)
• September 11, 2001?
• What would happen if
terrorists flew an
aeroplane into a
nuclear reactor?
Do we need nuclear power?
We face a possible Energy Gap in the years to come.
We need to reduce Carbon emissions!
Difficult to see how we will sustain current levels of
consumption without building new nuclear power.
But we still have a choice…
Nuclear Power
The UK Context
The answer?
• Collect interstellar hydrogen and turn it into helium
• Build a fusion reactor bigger than the Earth!
• Position the reactor about 93 million miles away
• Call it the Super Universal Neutrino machine (or SUN)
UK Nuclear Energy update
AREVA and
Electricité de
France's (EDF)
European
Pressurized Reactor
(EPR)
Westinghouse
Electric Company's
(WEC) AP1000
pressurized water
reactor (PWR)
Westinghouse Link
What is Nuclear Power?
Nuclear
Positives & Negatives
Nuclear Fission (6)
Chain reaction
• Nuclear phenomena has
always been associated
with great hopes and great
fears.
• Chicago
• 3:25 P.M. December 2,
1942
• Nuclear Age began
• Gain = 1.0006
Nuclear Fission (6)
Hopes
Arthur Compton
• One of the things that I shall not forget is the expressions
on the faces of some of the men. There was Fermi's face—
one saw in him no sign of elation. The experiment had
worked just as he had expected and that was that. But I
remember best of all the face of Crawford Greenewalt. His
eyes were shining. He had seen a miracle, and a miracle it
was indeed. The dawn of a new age. As we walked back
across the campus, he talked of his vision: endless
supplies of power to turn the wheels of industry, new
research techniques that would enrich the life of man, vast
new possibilities yet hidden.
Nuclear Fission (6)
Fears
Leo Szillard
• There was a crowd there and when it dispersed, Fermi and I stayed
there alone. Enrico Fermi and I remained. I shook hands with Fermi
and I said that I thought this day would go down as a black day in the
history of mankind.
• I was quite aware of the dangers. Not because I am so wise but
because I have read a book written by H. G. Wells called The World
Set Free. He wrote this before the First World War and described in it
the development of atomic bombs, and the war fought by atomic
bombs. So I was aware of these things.
• But I was also aware of the fact that something had to be done if the
Germans get the bomb before we have it. They had knowledge. They
had the people to do it and would have forced us to surrender if we
didn't have bombs also.
• We had no choice, or we thought we had no choice.
What is Nuclear Power?
Sounds like a lot of trouble: Why bother?
Nuclear Fission (6)
• 1 kg natural uranium has a volume of 50 cm3
– Produces 40 thousand kWh
– Equivalent to 16 tons of coal
• Nuclear energy is cleaner than coal
– Lower radioactive emissions
– Much less radioactive waste
• Conventional Power Stations
– Cheaper than nuclear because they don’t pay to clean up
their waste (CO2)
What is Nuclear Power?
OK so nuclear power is quite interesting.
Are there any downsides?
•
•
•
•
Link to nuclear weapons
Possibility of catastrophic explosion
Radioactive waste
Possibility of nuclear terrorism
Catastrophic Exposion
Chernobyl
• 26 April 1986
• 31 dead Immediately
• Ultimate death toll
– 100?
– 15,000?
Chernobyl
Effect on UK
Fall out from
atmospheric
atomic weapons
testing
Total radiation
emissions were
20 times less
than the
Annual
emissions from
dose
the atmospheric (micro
bomb tests from Sieverts)
1945 to 1963.
Chernobyl
1951
Year
1988
Radioactive waste (1)
Low level waste
• Low level waste
– Not very radioactive
– Much of it is
‘precautionary’
– No problem really
Radioactive waste (2)
Intermediate level waste
• Intermediate level waste
– Very radioactive
– Quite a lot of it
– Many different physical
forms
– No problem with heat
– Requires isolation for
thousands of years
Radioactive waste (3)
High level waste
• High level waste
–
–
–
–
–
Used fuel rods
Intensely radioactive
Requires cooling
Chemical mess
Requires ‘management’
for around 50 years
– Will remain intensely
radioactive for tens of
thousands of years
Radioactive waste (4)
Amounts in
cubic metres
No permanent resting place has been
found for the high level waste
Type of Waste
Year
2000
Year
2030
Low
424,000
1,411 ,000
Intermediate
100,000
260 ,000
High
1,200
3,000
Amounts in
cubic metres
Nuclear terrorism (1)
• September 11, 2001?
• What would happen if
terrorists flew an
aeroplane into a
nuclear reactor?
Do we need nuclear power?
You need to decide?
Does Britian need nuclear power?
Consider
• Our need to reduce carbon dioxide emissions
• The risks & benefits of nuclear technology
– Do we want all countries to have nuclear power?
• The effect on renewables
– Undermining or supporting?
• The need to make decisions soon
– Build the next generation of nuclear power stations?
– Or not?
Do we need nuclear power?
Does Britian need nuclear power?
Please find an answer!
Fusion
The answer?
• Collect interstellar hydrogen and turn it into helium
• Build a fusion reactor bigger than the Earth!
• Position the reactor about 93 million miles away
• Call it the Super Universal Neutrino machine (or SUN)
The End
Thanks for coming
to the course.
If you enjoyed
it, please tell
your friends and
colleagues
The Abercorn Arms
Church Road, Teddington
The Pub
Resources
Unused Slides
Electricity Generation
The case for nuclear power
So maybe we should keep nuclear power for a while?
What if one considers the supply of oil…
World Oil Production
(projections)
Oil prices will rise
Table
World Oil Production
We are close to ‘the midpoint’
GigaBarrels of Oil
Annual Production
World Oil Production
(the gap)
Electricity Generation
The case for nuclear power
But is oil relevant to this problem?
(still plenty of gas and coal)
Electricity Generation in UK
Pros and Cons
Type
Pros
Cons
CO2
Kg/kWh
Nuclear
Well suited to
supplying base load
Not popular
Waste Problem
0.010
Wind
Clean, plentiful,
available in the UK
Fluctuating Supply
Unsightly?
0.001
Radioactive health risks
Radon
Radioactive health risks
Height above sea level
Himalayas
15 km
0.01 mSv
per hour
10 km
0.005 mSv
per hour
7 km
0.001 mSv
per hour
2.5 km
Mexico City
0.0001 mSv
per hour
Electricity Generation in UK
1950
• Back in 1950
– Basically just coal
Crude Oil
10.4%
Hydro
0.1%
Coal
89.5%
Electricity Generation
CO2 Emissions
1990: 160 million tons
2005: 150 million tons
2010: target: 135 million tons
• Wind has problems of
– availability
– variability
• Availability
– On average a 3MW turbine only
generates 1 MW
– Sometimes, it generates nothing!
– Needs conventional back up
• Variability
– If wind speed changes
– 40 to 30 mph: No problem
– 30 to 20 mph: Output halves!
Percentage of maximum generation power
Wind Power
Environmental Change Institute
100
80
60
40
20
0
0
10
20
30
40
50
Wind Speed (miles per hour)
60
Sustainable Development
Commission
Sustainable Development Commission
The government’s independent watchdog on sustainable development
Report March 2006
“The two overriding concerns for Government are the need to:
• reduce carbon dioxide (CO2) emissions as part of efforts to
tackle climate change, and
• increase confidence in the security of energy supply.”
“Nuclear power is not the answer to tackling
climate change or security of supply”
What is Radioactivity(5)
Isotopes
• Nuclei with the same number
of protons, but different
numbers of neutrons are
called isotopes
• Nuclei with an ‘unbalanced’
ratio of protons and neutrons
are unstable
• Instability is caused by
electrical repulsion between
protonsactually a couple more
but don’t worry about them for
now
What is Radioactivity (7)
Summary
• Only nuclei with a ‘balanced’ number of protons and
neutrons are stable
Isotopes with
too many protons
Isotopes with
too many neutrons
Alpha decay
Beta decay
Emission of fast
moving helium nucleus
Emission of fast
moving electron
And gamma radiation
And gamma radiation
Current UK Nuclear Capacity
With retirement dates
• Current capacity is 12.4 GW
• Most of this will be retired by 2023
– Possibly much earlier
• If we don’t replace it with nuclear
power, what should we replace it
with?
– Energy savings?
– A CO2 free technology?
• If we don’t replace the power
stations with something, there will
be power cuts!
http://www.dti.gov.uk/energy/nuclear/technology/history.shtml
Power Station
Capacity GW
Retirement
Calder Hall
0.194
2003
Chapelcross
0.196
2005
Sizewell A
0.420
2006
Dungeness A
0.450
2006
Oldbury
0.434
2008
Dungeness B
1.110
2008
Wylfa
0.980
2010
Hinkley Point B
1.220
2011
Hunterston B
1.190
2011
Hartlepool
1.210
2014
Heysham 1
1.150
2014
Heysham 2
1.250
2023
Torness
1.250
2023
Sizewell B
1.188
2035
Quiz
What is polonium 210?
• Polo-nium 210 is the key ingredient in Polo™ mints
• Po-lonium 210 caused Po™ to be a bit strange
•
210Po
is a radioactive isotope of polonium with 82 protons
and 128 neutrons making a total of 210 nuclear particles