the uk adsr programme

The UK ADSR programme

Roger Barlow

FFAG08

Manchester, 4th September 2008

Roger Barlow UK ADSR Programme Slide 2

History

BASROC/CONFORM “Basic Technology” project for nsFFAGs

Funded on the basis that nsFFAGs were an exploitable technology: we can build better+cheaper accelerators and open up lots of new applications

1. Build EMMA as proof of principle

2. Design PAMELA as a flagship application

3. Look for other applications ‘from Archaeology to Zoology’


Application #2ADSRs

Accelerator Driven Subcritical Reactors

“Manifestly Safe”Used for power and

for waste transmutation

Can use Thorium as fuel

Accelerator

Spallation Target

Core


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• Thoria – ThO2 – has high melting point


Energy Amplifier (Rubbia)

Idea has been around for years

Nobody’s built one yet!

Feeling is that the accelerator is the weak point.

Also MYRRHA, KURRI and others


UK interest

Past/PresentSafer? But our reactors are safe…Waste problem? But we’ve solved it…

Present/FutureIncreased awareness of power problem• Global warming• Fuel prices• Global politicsHostility to conventional Nuclear Power continuesInterest from Research Councils and individuals


What energy do we need?

What energy do we need?

Variation with proton energy of:(i) the neutron multiplicity np(ii) neutron yield per unit energy of incident proton (np/Ep)

(Calculated using using MCNPX)

The energy gain of an ADSR is directly proportional to np/Ep.

Clearly there is little need for proton energies greater than 1GeV

Taken from Bob Cywinski


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 MW Compare: PSI proton cyclotron: 590 MeV, 72 MeV injection2mA, 1MW


Specification

Cyclotron

Energy too high for classical cyclotron. On the edge for other types

FFAG

Looks like the answer

Similar to proton therapy except higher current and no need for variable energy extraction

Very similar to neutrino factor proton driver

Linac

Can do the job. But VERY expensive

Synchrotron

Current far too high.

Complicated (ramping magnets)


Achieving high current

Frequency must sweep (factor ~2)Need high duty cycle: • Will not achieve cyclotron-like 100% but

have to get within an order of magnitude• Need to accelerate several pulses at

slightly different energies with the same sweeping frequency

• Need several RF frequency systems (in same cavity or separate cavities)


Reliability

• No long shutdowns – lose money

• No unplanned shutdowns – lose money and customers

• Spallation target runs hot. If beam stops, target cools and stresses and cracks: no more than 3 trips per year

Cars and planes achieve this…


Achieving reliability

• Component Underrating

• Redundancy (e.g. Ion source)

• Fault Tolerance

• Scheduled inspection and replacement programme

Has to be integrated into the design


Reliability and RF

RF in a linac: Many cavities. Failure of one does not kill beam. Just gets slightly less energy

RF in an FFAG: many cavities

Failure of one should not kill beamJust gets slightly less energy, or takes slightly longer to accelerate

Unless HNJ scheme is used. Probably ruled out


The ultimate redundancy

Could have several (3) accelerators for one reactor core

If FFAGs are really as cheap as we’re promising


UK Activities

• Grouping of interested people (accelerator scientists, reactor engineers, economists..)

• Held 2 1-day workshops this year• Couple of small projects (EPSRC funded)

to look at possibilities• Increasing funding opportunities

anticipated • Upcoming 3 day workshop here, next

week


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

Forthcoming…


Conclusions

Things are moving fast.

Two years ago my worry was that no-one wanted to know.

Today my worry is that we’re going to get trampled in the rush.

the uk adsr programme

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