ADSR systems and their contribution to our energy needs

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ADSR systemsand their contribution to our
energy needs

• Roger Barlow
• DIUS visit
• Manchester, 16th September 2008

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Problem

• Fossil Fuels
• Cause global warming
• Politically dangerous
• Becoming less abundant

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Solution

• Renewable energy?
• Restrict consumption??
• Nuclear power ???

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Nuclear power

• Problems (real or perceived)
• Dangerous
• Long-term waste disposal
• Proliferation of nuclear weapons

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Reactors
Each fission absorbs 1 neutron and produces
2.5 Some neutrons lost, leaving k neutrons to
produce k fissions

• Conventional
• Run with k1
• Exactly klt1 stops
• kgt1 explosion

• Sub Critical
• Run with klt1
• Use accelerator to supply extra neutrons
• Hence Accelerator Driven Subcritical Reactor
  (ADSR)

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ADSRs
Spallation Target

• Manifestly Safe
• Switch off accelerator and reaction stops
• Energy balance is OK need 5-10 of power to run
  accelerator
• Can use Thorium as fuel

Accelerator
Core
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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

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Energy Amplifier (Rubbia)
Idea has been around for years Nobodys built one
yet! Feeling is that the accelerator is the weak
point.
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Waste from ADSR
Needs storing but not forever
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Accelerator requirements

• Proton Energy 1 GeV
• For 1GW thermal power
• Need 3 1019 fissions/sec (200 MeV/fission)
• 6 1017 spallation neutrons/sec (k0.98 gives 50
  fissions/neutron)
• 3 1016 protons/sec (20 spallation neutrons each)
• Current 5 mA. Power 5 MW
• Reliable! 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, 1MW
• ISIS synchrotron 800 MeV, 0.2mA, 0.1 MW
• Many trips per day

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Accelerator types
Synchrotron Current far too high. Complicated
(ramping magnets)
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
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FFAG ACCELERATORSFixed Field Alternating Gradient
All cyclic accelerators use magnetic fields to
contain the particles As the energy increases

• Cyclotron
• Constant Field
• Orbit radius increases

FFAG Radius increases slightly Particles move
from low field to high field region
Synchrotron Constant Radius Field is ramped up
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FFAG
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EMMAWorlds firstnsFFAG
First Beam 2009
Design
Site
Production
Prototypes
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A way forward

• 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

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ThorEA
From the Articles of Association

• 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 youre interested, see www.thorea.org

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Summary

• ADSRs provide a possible form of Nuclear Power
  that avoids the problems of
• Critical accidents
• Long-lived waste
• Proliferation
• FFAGs may provide the best accelerator technology
• We (UK, Particle Physicists, Manchester,
  Cockcroft Institute) are working hard to make it
  happen