170 likes | 277 Views
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 ???.
E N D
ADSR systemsand their contribution to our energy needs Roger Barlow DIUS visit Manchester, 16th September 2008
Problem Fossil Fuels • Cause global warming • Politically dangerous • Becoming less abundant UK ADSR Programme
Solution • Renewable energy? • Restrict consumption?? • Nuclear power ??? UK ADSR Programme
Nuclear power Problems (real or perceived) • Dangerous • Long-term waste disposal • Proliferation of nuclear weapons UK ADSR Programme
Conventional Run with k=1 Exactly: k<1 stops k>1 explosion Sub Critical Run with k<1 Use accelerator to supply extra neutrons Hence: Accelerator Driven Subcritical Reactor (ADSR) Reactors Each fission absorbs 1 neutron and produces ~2.5 Some neutrons lost, leaving k neutrons to produce k fissions UK ADSR Programme
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 UK ADSR Programme
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 UK ADSR Programme
Energy Amplifier (Rubbia) Idea has been around for years Nobody’s built one yet! Feeling is that the accelerator is the weak point. UK ADSR Programme
Waste from ADSR Needs storing – but not forever UK ADSR Programme
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 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 UK ADSR Programme
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 UK ADSR Programme
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 UK ADSR Programme
FFAG UK ADSR Programme
EMMA:World’s firstnsFFAG First Beam 2009 Design Site Production Prototypes UK ADSR Programme
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 UK ADSR Programme
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 you’re interested, see www.thorea.org UK ADSR Programme
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 UK ADSR Programme