adsr systems and their contribution to our energy needs
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ADSR systems and their contribution to our energy needs. Roger Barlow DIUS visit Manchester, 16 th September 2008. Problem. Fossil Fuels Cause global warming Politically dangerous Becoming less abundant. Solution. Renewable energy? Restrict consumption?? Nuclear power ???. - PowerPoint PPT PresentationTRANSCRIPT
ADSR systemsand their contribution to our energy needs
Roger Barlow
DIUS visit
Manchester, 16th September 2008
Roger Barlow UK ADSR Programme Slide 2
Problem
Fossil Fuels
• Cause global warming
• Politically dangerous
• Becoming less abundant
Roger Barlow UK ADSR Programme Slide 3
Solution
• Renewable energy?
• Restrict consumption??
• Nuclear power ???
Roger Barlow UK ADSR Programme Slide 4
Nuclear power
Problems (real or perceived)
• Dangerous
• Long-term waste disposal
• Proliferation of nuclear weapons
Roger Barlow UK ADSR Programme Slide 5
Reactors
ConventionalRun with k=1
Exactly: k<1 stopsk>1 explosion
Sub CriticalRun with k<1
Use accelerator to supply extra neutrons
Hence: Accelerator Driven Subcritical Reactor (ADSR)
Each fission absorbs 1 neutron and produces ~2.5
Some neutrons lost, leaving k neutrons to produce k fissions
Roger Barlow UK ADSR Programme Slide 6
ADSRs
“Manifestly Safe”Switch off accelerator and
reaction stopsEnergy balance is OK:
need 5-10% of power to run accelerator
Can use Thorium as fuel
Accelerator
Spallation Target
Core
Roger Barlow UK ADSR Programme Slide 7
Thorium
Fertile, not fissile 232Th +n 233U • Much smaller waste problems (no long-
lived actinides)• Proliferation resistant
– No 235U equivalent– Fissile 233U contaminated by ‘too hot to
handle’ 232U
• Abundant. (Like Lead) And spread around
Roger Barlow UK ADSR Programme Slide 8
Energy Amplifier (Rubbia)
Idea has been around for years
Nobody’s built one yet!
Feeling is that the accelerator is the weak point.
Roger Barlow UK ADSR Programme Slide 9
Waste from ADSR
Needs storing – but not forever
Roger Barlow UK ADSR Programme Slide 10
Accelerator requirements
Proton Energy ~ 1 GeV For 1GW thermal power:• Need 3 1019 fissions/sec (200 MeV/fission)• 6 1017 spallation neutrons/sec (k=0.98 gives 50 fissions/neutron)• 3 1016 protons/sec (20 spallation neutrons each)Current 5 mA. Power = 5 MWReliable! Spallation target runs hot. If beam stops, target cools and
stresses and cracks: no more than 3 trips per year
Compare: PSI cyclotron: 590 MeV, 2mA, 1MWISIS synchrotron: 800 MeV, 0.2mA, 0.1 MWMany trips per day
Roger Barlow UK ADSR Programme Slide 11
Accelerator types
Cyclotron
Energy too high for classical cyclotron. On the edge for other types
FFAG
Looks like the answer
Similar to proton therapy machine except higher current and no need for variable energy extraction
Very similar to neutrino factory proton driver
Linac
Can do the job. But VERY expensive
Synchrotron
Current far too high.
Complicated (ramping magnets)
Roger Barlow UK ADSR Programme Slide 12
FFAG ACCELERATORSFixed Field Alternating Gradient
Cyclotron
Constant Field
Orbit radius increases
All cyclic accelerators use magnetic fields to contain the particles
As the energy increases:
Synchrotron
Constant Radius
Field is ramped up
FFAG
Radius increases slightly
Particles move from low field to high field region
Roger Barlow UK ADSR Programme Slide 13
FFAG
Roger Barlow UK ADSR Programme Slide 14
EMMA:World’s firstnsFFAG
Design
Prototypes
Site
Production
First Beam
2009
Roger Barlow UK ADSR Programme Slide 15
Formation of the Thorium Energy Amplifier Association: Universities and labs and industry
A research consortium aimed at • Networking (website, workshops)• Sharing knowledge, within and outside UK• Collaborative response to funding opportunities• Design of a Thorium ADSR, aimed at power generation
with transmutation as bonus. FFAG is baseline accelerator
Inaugurated here last week
A way forward
Roger Barlow UK ADSR Programme Slide 16
ThorEA
• The Thorium Energy Amplifier Association – hereafter known as ThorEA – is an affiliation of academic institutions, research laboratories, industrial companies, and individual scientists, engineers, technologists and policy specialists who share a common interest in developing thorium as a nuclear fuel in accelerator-driven systems such as the energy amplifier.
• The overriding purpose of ThorEA is to provide a platform for discussion and a focus for action in thorium fuel and energy
amplifier technology and related topics including transmutation.
If you’re interested, see www.thorea.org
From the Articles of Association:
Roger Barlow UK ADSR Programme Slide 17
Summary
ADSRs provide a possible form of Nuclear Power that avoids the problems of
• Critical accidents• Long-lived waste• ProliferationFFAGs may provide the best accelerator
technologyWe (UK, Particle Physicists, Manchester,
Cockcroft Institute) are working hard to make it happen