ADSR systems UK activity

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					     ADSR systems
      UK activity
        Roger Barlow
Fermilab 24th September 2009
     Saving the

                   Global warming
                     due to CO2
         Safety Thorium
               Nuclear Waste
 Fossil fuels Power
running out      ADSRs

         Roger Barlow - UK ADSR programme   2
               ADSRs 101

• Uses Thorium (abundant, widespread)
• Spallation Neutrons:

• Accelerator consumes 5-10% of power
• Does not generate Actinides
• Consumes Actinides and nastiest fission
  products (I, Tc) from conventional reactors
• Very proliferation resistant
                 Roger Barlow - UK ADSR programme   3
          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
                 Roger Barlow - UK ADSR programme   4
           Various models

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

                Roger Barlow - UK ADSR programme   5

  The Thorium Energy Amplifier Association
                         Founded 1 year ago
                         3-4 workshops/year
                         Co-ordinated research bids                From:
                         Outreach and publicity                    Cockcroft
                         Links with European and                   JAI
                         US co-enthusiasts                         Imperial, Glasgow,
Members:                                                           Cambridge, Brunel,
78 (loose) or 40                                                   Huddersfield
(public)                                                           Industry
Accelerator Scientists              What follows are
                                    highlights from                Non-UK
Particle Physicists
Nuclear Physicists                  recent workshops,
Nuclear Engineers                   plus some thoughts
Economists                          of my own
…                               Roger Barlow - UK ADSR programme                        6
         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

                      Roger Barlow - UK ADSR programme   7
              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
• 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.

                   Roger Barlow - UK ADSR programme            8
It’s in the middle of the Thames valley
We may have a problem if the
neighbours find out and object…

                              Roger Barlow - UK ADSR programme   9
             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)

                      Roger Barlow - UK ADSR programme             10
Thorium Fuel

   Taken from a talk by:
      Bob Cywinski
     School of Applied Sciences
     University of Huddersfield
                           Thorium as fuel

Advantages                                                          Disadvantages
Thorium supplies
                                    232Th        g                  No fission until 233U is
plentiful                                        233Th              produced
                                n                       b
Robust fuel and waste
form                                                 22 mins
                                    233U         233Pa
Generates no Pu and                                     b
fewer higher actinides                 27 days

233Uhas superior fissile

              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
                                 Roger Barlow - UK ADSR programme                        12
Possibility 1: Plutonium
                                   The Indian approach: thermal
                                   Thorium Breeder Reactor

                                   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

                                   Problems with waste and security
                                                Jagannathan, Pal
                                                Energy Conversion and Management
                                                47 (2006) 2781

        Roger Barlow - UK ADSR programme                                  13
Possibility 1: Plutonium

Seedless thorium cluster

                                                           ATBR core

                                                                   Jagannathan, Pal
                                                                   Energy Conversion and Management
                                                                   47 (2006) 2781

  Seeded fuel cluster   Roger Barlow - UK ADSR programme                                     14
          Possibility II: The ‘pure’

Load up with
pure Thorium

Switch on
accelerator and
run for ~6
months before
getting any
power out

Is this

                     Roger Barlow - UK ADSR programme   15
     Possibility III: Transitional
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 accelerator+target


           232Thto 233U conversion can be better optimised,
           with mitigation against detrimental neutron
           absorption by 233Th and 233Pa
           Modifications to existing reactors are not necessary

           Wider global exploitation of nuclear technology is possible

           Fuel preparation and burn cycles are decoupled

                      Roger Barlow - UK ADSR programme                       16
      Possibility III:
 Transitional technology

The Challenges

    Optimisation of proton beam characteristics; spallation
    target/fuel rod geometries; moderator and reflector geometries

    Optimisation of irradiation cycles; consideration of the neutron
    energy spectrum and related absorption characteristics of
    232Th, 233Th, 233Pa

    Characterisation of the 233U fission during and after irradiation

    Selection of optimal fuel form; characterisation of material
    (physical, chemical and engineering properties under extreme

                 Roger Barlow - UK ADSR programme                       17
Possibility III: Transitional

                                              High power (MW)
                                              proton beam

                                              Miniature spallation target
                                              in central bore of fuel
                                              element assembly

           Roger Barlow - UK ADSR programme                                 18
                        Fuel types ?
Thorium Metal
Ductile, can be shaped. High
conductivity .

Thoria -ThO2
High melting point, most stable oxide
                                                 pyC       SiC   C    MOX fuel pellet
Thorium Nitrides and Carbides                                    TRISO fuel (ORNL)
Carbides have already been successfully
used. The use of nitrides is also possible

Cermet                                                                               Cermet fuel
Fine oxide partilcles embedded                                                       element
in a metallic host.

                        Roger Barlow - UK ADSR programme                                     19
                Materials Properties

LWR fuel rod element
    Crack formation
    Substantial grain growth in
     centre (ie in hotter region)
    Small gap at pellet-cladding

                                                        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 !

                     Roger Barlow - UK ADSR programme                            20
                 The next step....
STFC are funding a two year
scoping study of the thorium fuel
rod concept through PNPAS
(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).
                     Roger Barlow - UK ADSR programme   21
Do we need fuel
 Thorium fuel rods: once-through or recycle?
 (Current strategy for Uranium is once-through, as
    extracting Plutonium leads to stockpiles of the
 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…

      Roger Barlow - UK ADSR programme                22
“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
So we need to recycle the 233U. Messy
                        Roger Barlow - UK ADSR programme   23

“If the beam stops, the reactor stops”
                - safety mantra
If the accelerator drops out, the reactor stops
1) Stress, thermal shock, target breakdown…
2) You are now losing money VERY fast (electricity spot market)
Suggestion that at most ~5 trips (of >1 second) / year are
Long way beyond today’s accelerator systems: (Analysis by R
    Seviour of data from SINQ and others)

                       Roger Barlow - UK ADSR programme           24
Many sophisticated machines are reliable
Achieving reliability is a science (FMEA*):
• Parallelism (even >1 accelerator)
                                            Cost money
• Under-rating
                                            Need full
• Graceful failure                          knowledge of
                                            whole system
• Scheduled preventive maintenance
• Sticking to the original spec             Build in from
                                            start of design
                                                       *Failure Mode
                                                       and Effects
                    Roger Barlow - UK ADSR programme
                                                       Analysis        25

• 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
- Allowable capital cost
                               (From R Seviour: ThorEA workshop, Glasgow, 2009)
                           Roger Barlow - UK ADSR programme                  26
               Going forwards

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

                       Roger Barlow - UK ADSR programme   27
              Straw man
            scheme: AESIR
Accelerator Energy System with
  Inuilt Reliability
Design and build a Thorium
  ADSR, hopefully with an
  nsFFAG providing the
(Other accelerator solutions
  are acceptable.)
                 Roger Barlow - UK ADSR programme   28
                     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

                          Roger Barlow - UK ADSR programme              29
                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
                      Roger Barlow - UK ADSR programme   30
          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

                 Roger Barlow - UK ADSR programme   31

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

                 Roger Barlow - UK ADSR programme   32

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