ADSR systems UK activity

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ADSR systemsUK activity

• Roger Barlow
• FFAG09
• Fermilab 24th September 2009

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Saving the planet
Thorium fuelled ADSRs
Nuclear Power
Global warming due to CO2 emissions
Safety
Waste
Fossil fuels running out
Proliferation
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ADSRs 101

• Uses Thorium (abundant, widespread)
• Spallation Neutrons 232Th?233Th?233Pa?233U?fissio
  n
• Accelerator consumes 5-10 of power
• Does not generate Actinides
• Consumes Actinides and nastiest fission products
  (I, Tc) from conventional reactors
• Very proliferation resistant

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FFAGs for ADSRs

• Accelerator requirements
• 1 GeV - rules out cyclotron
• 10 mA - rules out synchrotron
• Cheap - rules out Linac
• FFAG fits the picture. Design like medical
  accelerators but higher energy and much higher
  current

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Various models

• (a) ADSR as standard 1-2 GW power station for
  advanced energy-consuming society (US,UK)
• ADSR as 500 MW power station suitable for
  developing country
• ADSR run on same site as cluster of conventional
  reactors to consume waste products
• We currently favour (b) as a first step

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ThorEA

• The Thorium Energy Amplifier Association

Founded 1 year ago Website www.thorea.org 3-4
workshops/year Co-ordinated research
bids Outreach and publicity Links with European
and US co-enthusiasts
From Cockcroft JAI Imperial, Glasgow, Cambridge,
Brunel, Huddersfield Industry Non-UK
Members 78 (loose) or 40 (public) Accelerator
Scientists Particle Physicists Nuclear
Physicists Nuclear Engineers Economists
What follows are highlights from recent
workshops, plus some thoughts of my own
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Imperial College CONSORT Research Reactor(Recent
talk by Dave Wark)
Dave knows someone who has a spare reactor we
might use
100 kW, pool-type enriched U/Al fuel, light
water moderated Already licensed
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Basic Idea Modify CONSORT into ADSR.

• Build/buy small proton accelerator (few - 10 kW
  total power) for reactor facility.
• Insert small spallation target either in place of
  one fuel assembly or above the core.
• Leave control rods in place to scram reactor and
  make it sub-critical.
• Use sample insertion locations/devices (or add
  more) to place other fuel in/near core.
• Probably increase instrumentation of the reactor
  to measure neutron profiles, etc.

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Its in the middle of the Thames valley We may
have a problem if the neighbours find out and
object
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CONSORT/ADSR Experiments to be done.

• Breeding 233U fuel from 232Th in an ADSR.
• Burning Pu in an ADSR.
• Burning MA in an ADSR.
• Burning LLFP in an ADSR.
• Effects of all of this on the reactivity, neutron
  profile, and other parameters of the reactor
  reactivity feedback in an ADSR has not been
  measured up to now.
• Measure all of this as a function of k by
  changing control rod positions.
• Use all this to benchmark simulations.
• Thought of before but not actually done
  (TRADE/TRIGA)

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Thorium Fuel Rods
Taken from a talk by Bob Cywinski School of
Applied Sciences University of Huddersfield
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Thorium as fuel
Disadvantages No fission until 233U is produced

Advantages Thorium supplies plentiful Robust fuel
and waste form Generates no Pu and fewer higher
actinides 233U has superior fissile properties

It is generally considered that the neutrons
necessary to produce 233U from 232Th must be
introduced by seeding the Th fuel with 235U or Pu
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Possibility 1 Plutonium seeding

• The Indian approach thermal Thorium Breeder
  Reactor (ATBR)
• Calculations suggest PuO2 seeded thoria fuel
  gives excellent core characteristics, such as
• two years cycle length
• high seed output to input ratio
• intrinsically safe reactivity
• coefficients
• Problems with waste and security

Jagannathan, Pal Energy Conversion and Management
47 (2006) 2781
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Possibility 1 Plutonium seeding
Seedless thorium cluster
ATBR core
Jagannathan, Pal Energy Conversion and Management
47 (2006) 2781
Seeded fuel cluster
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Possibility II The pure Thorium-ADSR
Load up with pure Thorium Switch on accelerator
and run for 6 months before getting any power
out Is this economically possible?
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Possibility III Transitional technology
Production of ready-engineered Th fuel rods for
direct deployment in conventional nuclear
reactors, with fertile to fissile conversion
achieved through dedicated spallation charging
from an acceleratortarget
Why?
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Possibility III Transitional technology
The Challenges
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Possibility III Transitional technology
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Fuel types ?
Thorium Metal Ductile, can be shaped. High
conductivity .
Thoria -ThO2 High melting point, most stable
oxide known.
pyC
SiC
C
MOX fuel pellet
Thorium Nitrides and Carbides Carbides have
already been successfully used. The use of
nitrides is also possible
TRISO fuel (ORNL)
Cermet fuel element
Cermet Fine oxide partilcles embedded in a
metallic host.
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Materials Properties
LWR fuel rod element

• Crack formation
• Substantial grain growth in
• centre (ie in hotter region)
• Small gap at pellet-cladding
• interface

Effects of irradiation and thermal cycling on
thorium fuel assemblies must be studied and
characterised These fuel rods may be in the
reactor for several years !
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The next step....
STFC are funding a two year scoping study of the
thorium fuel rod concept through PNPAS
scheme (Barlow and Cywinski)

• The programme will support two PDRAs for
• GEANT4/MCNPX simulations
• Materials studies

The programme may progress as far as experimental
tests , eg at TRIUMF, where FERFICON experiments
were carried out in the 70s (these would allow
irradiation by protons at up to 20nA at 450MeV).
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Do we need fuel reprocessing?

• Thorium fuel rods once-through or recycle?
• (Current strategy for Uranium is once-through, as
  extracting Plutonium leads to stockpiles of the
  stuff.)
• Thorium fuel rods stay in the reactor for years
  rather than months poisonous fission products
  build up much more slowly
• Do we then have to process them, or just leave
  them in a depository somewhere?
• The latter looked attractive, but

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Waste

• Thorium Reactors produce no long-term waste
• Up to a point. Ignores the 233U which has a half
  life of 160,000 years.
• Thorium is proliferation-resistant as the
  fissile 233U is inescapably contaminated by 232U
  which renders it too hot to handle
• For a while. 232U has a half life of 72 years.
• So we need to recycle the 233U. Messy chemistry
  

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Reliability

• If the beam stops, the reactor stops
• - safety mantra
• If the accelerator drops out, the reactor stops
• Stress, thermal shock, target breakdown
• You are now losing money VERY fast (electricity
  spot market)
• Suggestion that at most 5 trips (of gt1 second) /
  year are permissible
• Long way beyond todays accelerator systems
  (Analysis by R Seviour of data from SINQ and
  others)

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Achieving Reliability

• Many sophisticated machines are reliable
• Achieving reliability is a science (FMEA)
• Parallelism (even gt1 accelerator)
• Under-rating
• Graceful failure
• Scheduled preventive maintenance
• Sticking to the original spec

Cost money Need full knowledge of whole
system Build in from start of design
Failure Mode and Effects Analysis
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Considerations

• DC Magnets are fairly reliable provided they are
  maintained (e.g. renew coolant pipes)
• Ion sources are unreliable but can be duplicated
• RF cavities frequently break down. Need not be
  catastrophic for Linac and FFAG (consider ILC).
  But rules out harmonic number jump scheme
• But first
• Define break in provision of service ( 1 sec, 1
  min, ....)
• - How many breaks can we live with ( 1,5,... per
  year)
• Allowable capital cost
• (From R Seviour ThorEA workshop, Glasgow, 2009)

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Going forwards

• UK Science minister interested
• Asked for a report on possibilities
• Now written 91 pages to be delivered soon
• Have been liaising with civil servants so have
  produced something which should be welcome
• Makes case for 300M development programme

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Straw man scheme AESIR

• Accelerator Energy System with Inuilt Reliability

Design and build a Thorium ADSR, hopefully with
an nsFFAG providing the accelerator (Other
accelerator solutions are acceptable.)
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Stage I LOKI

• The Low-key demonstrator
• 35 MeV H- system
• High current. (1 mA? 10 mA?)
• Commercial source
• RF Quadrupole
• Standard Linac
• Study reliability and build it in from the start.
  Learn from mistakes
• Looks like the Front End Test Stand?? Copy? Move?
• Also measurements of cross sections on Thorium
  (at CERN?),simulations, materials studies

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Stage 2 FREA

• FFAG Research for the Energy Amplifier
• Add a 2nd stage ring boost energy to 390 MeV
• Why 390? Pion production. But 300 would still
  be interesting
• Produces spallation. Not as much as 1 GeV, but
  enough to be interesting.
• Continue to emphasise reliability. Increase
  Current to 10 mA
• Use a proton nsFFAG with a cyclotron as
  fallback. Or Linac
• Gives useful proton machine (c.f. TRIUMF, PSI).
  99mTc production?
• Links to proton therapy

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Stage 3 Thor
Add a second ring to give 1 GeV nsFFAG, with RCS
and Linac as backup options Use with a real
target and nuclear core for production Need
private funding 1Bn
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Conclusions

• Things are moving
• More people
• More ideas
• Serious possibility of some sort of funding