ADS Developments in Britain Roger Barlow Manchester University and the Cockcroft Institute Workshop on Applications of High Intensity Proton Beams Fermilab:

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.”

Tuesday, October 20, 2009 Roger Barlow: ADS developments in Britain 2

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

http://www.thorea.org/

WorkshopsLast one in Glasgow September

7-8Next one Daresbury November

24Talks accessible from the website


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


What it does(2)

Neutron production: MC validation

Tuesday, October 20, 2009 Roger Barlow: ADS developments in Britain Slide 5

Slides from work by Cristian Bungau

Validate GEANT4 against MCNPX, FLUKA, and data

Modelling spallation


Energy deposition from the beam


Publicity/outreach

Website, Articles and press releases, Talks to the public and politicians


What it does(3)

Drayson Report


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


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)


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


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


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.


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


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


ENERGY

LUMINOSITY

RELIABILITY

The possibilities

Cyclotrons• 1 GeV is really pushing the

edge

Synchrotrons• 10 mA is really pushing the

edge


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

Documents

ADS Developments in Britain Roger Barlow Manchester University and the Cockcroft Institute Workshop on Applications of High Intensity Proton Beams Fermilab: