ADS Developments in Britain
Roger BarlowManchester University and the
Cockcroft InstituteWorkshop on Applications of High
Intensity Proton BeamsFermilab: October 20th 2009
What it is
An organisation“ThorEA is a research association to promote
the use of thorium-fuelled energy amplifier systems as a safe, sustainable and publicly-acceptable of nuclear power. The goal of the organisation is the construction of a thorium-fuelled ADSR (accelerator-driven subcritical reactor) in the United Kingdom.”
An organisation“ThorEA is a research association to promote
the use of thorium-fuelled energy amplifier systems as a safe, sustainable and publicly-acceptable of nuclear power. The goal of the organisation is the construction of a thorium-fuelled ADSR (accelerator-driven subcritical reactor) in the United Kingdom.”
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Members:80 (loose) or 40 (public)Accelerator ScientistsParticle PhysicistsNuclear PhysicistsNuclear EngineersEconomists…
Members:80 (loose) or 40 (public)Accelerator ScientistsParticle PhysicistsNuclear PhysicistsNuclear EngineersEconomists…
From:Cockcroft, JAI, RAL, DLImperial, Glasgow, Cambridge, Brunel, HuddersfieldIndustryNon-UK
From:Cockcroft, JAI, RAL, DLImperial, Glasgow, Cambridge, Brunel, HuddersfieldIndustryNon-UK
A websitewww.thorea.org
WorkshopsLast one in Glasgow September
7-8Next one Daresbury November
24Talks accessible from the website
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What it does(1)
Funding bids: Partnerships formed to respond to
opportunitiesSome successes already:– Use of FFAG for ADSR– Economics of ADSR– Use of Thorium fuel rods in conventional reactors by pre-
exposure more applications on the way
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What it does(2)
Neutron production: MC validation
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Slides from work by Cristian Bungau
Validate GEANT4 against MCNPX, FLUKA, and data
Modelling spallation
Tuesday, October 20, 2009 Roger Barlow: ADS developments in Britain Slide 6
Energy deposition from the beam
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Publicity/outreach
Website, Articles and press releases, Talks to the public and politicians
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What it does(3)
Drayson Report
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Science Minister visited Daresbury: we told him about ADSRs and he asked for a report. Now ready (85 pages) and submitted.
Makes the case for a 5 year £300M R and D program, leveraging £1-2Bn private investment.
3 stage acceleration system: 35 MeV, 400 MeV, 1 GeV
Design Choices• Thorium fuelled fast reactor• Emphasize energy production
with transmutation as extra benefit• 1 GW Thermal.• Go for production reactor as 1st system• k=0.985 • Accelerator (or multiple accelerators) deliver 10 mA of protons at 1 GeV• Lead as target+coolant+moderator• Recycle spent fuel rods after ~10 years• FFAG accelerator
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Those are my principles, and if you don't like them... well, I have others. Groucho Marx
Acceleration System
The FFAG is our preferred solution:
EMMA, first nsFFAG, being built at Daresbury (starting soon)
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FFAGs101
Magnetic field fixed in time but varies in space, so more energetic particles see stronger field
Keeping constant betatron tune requires gentle B ~ rk field variation
Relaxing this constraint permits simpler more compact magnets: the nonscaling FFAG
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FFAG Pros and Cons
Advantages (compared to a Synchrotron)
• DC magnets: cheap and reliable
• Fast acceleration. Not limited by magnet iron. Acceleration to 1 GeV in ~1000 turns envisaged (say 50 m radius ring: take ~ 1 ms)
Disadvantages• Complicated Magnet shape• May require varying RF
frequency• Limited gain in energy
(momentum change factor 2-5 depending on design)
• nsFFAG principle not yet proven
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Duty cycle
Synchrotron-styleInject 1 pulse
AccelerateExtract
For 10 mA at 1 kHz, Q=10 μC=6 1013 protons/bunchCompare space charge limits ~
1013 protons/bunchHarmonic factor (bunches/turn)
may help a bit
Cyclotron-styleCW injectionAcceleration
CW extractionOnly 6 1010 particles/bunch.
EasyBut sweeping the RF frequency
limits the duty cycle.
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Reliability
Requirement ~5 trips/year. (Where does this come from? Needs checking.)
• Thermal stresses in window and target• Thermal stresses in the core and its components• Economics: a 1 GW plant can’t just drop out of
the Grid when it feels like it, and the financial system will ensure this
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Reliability: the Next Accelerator Frontier
How to achieve this: Needs redundancy and robustness– Ion Source: use several– Magnets: reliability possible with DC
magnets– Multiple accelerators– RF: components will fail. Must not be
fatal. Probably rules out SOC, RLA, Harmonic number jump and other clever schemes
– Also vacuum, power, etc
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ENERGY
LUMINOSITY
RELIABILITY
The possibilities
Cyclotrons• 1 GeV is really pushing the
edge
Synchrotrons• 10 mA is really pushing the
edge
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FFAGsLinacs• Ideal but nonexistant. As
yet.• Seriously Expensive
Conclusions
• The UK is waking up• We have a wide range of specialists working
together across discipline boundaries• Check out the ThorEA website, and send me an
email to join• We are very much aware that we have a lot to
learn from others • Small amounts of funding are coming through.
Larger sums are possible Tuesday, October 20, 2009 Roger Barlow: ADS developments in Britain 18