Presentation by:

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Future Power Production System

• Presentation by
• M. I. Al-Jarallah
• Department of Physics
• King Fahd University of Petroleum Minerals
• Dhahran-Saudi Arabia
• Contact 009 663 860 2281
• Email mibrahim_at_kfupm.edu.sa
• Homepage
• http//faculty.kfupm.edu.sa/phys/mibrahim

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Future Power Production System

• Introduction
• Advantages Disadvantages
• Available ADSs and Those in The Design Stages
• Diagrams of the Facilities
• Target, Fuel, Coolant and Accelerator Types
• The Physics of Spallation
• Applications of ADSs
• Conclusion

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1. Introduction

• Neutrons resulting from interaction of
  relativistic projectiles with extended targets
  e.g. protons on lead, can be used for energy
  production and nuclear waste transmutation, in
  sub-critical nuclear assemblies. These systems
  are known as Accelerator Driven Systems ADS,
  and are also called AD Sub-critical Reactors
  ADSR. They are designed to replace or
  supplement conventional nuclear reactors as
  neutron sources.
• In such system, an accelerator produces an
  energetic and intense proton beam several
  hundred MeV to a few GeV, 5 100 mA, which is
  made interact with a cooled target consisting of
  lead or other high mass nuclei to produce fast
  neutrons through Spallation Process. Spallation
  Process is the nuclear reaction of high energy
  protons with nuclei.
• These neutrons can then be moderated and used for
  some of the same purposes as the neutrons that
  are produced in a reactor through the fission
  process. Similar ideas were first proposed more
  than fifty years ago !

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2. Advantages and Disadvantages of ADS

• A) Advantages of an ADS over conventional
  reactors
• Greater efficiency in neutron production
• Greater safety in operation
• Less production of unwanted radioactive materials
  in particular, Pu or other transuranium actinides
  by using thorium fuel. Thorium is more abundant
  than Uranium, it generates much less transuranic
  actinides among the radioactive waste and the
  risk of nuclear proliferation is negligible.
  Thorium based thermal reactor cannot operate in a
  satisfactory way on a self sufficient 232Th
  233U cycle. Evidently an external supply of
  neutrons remove the above mentioned limitations.

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• B) Disadvantages of ADS compared with existing
  reactors
• The need to construct accelerators that are
  considerably more powerful than existing one.
• The need to accurately determine many as yet
  unknown or poorly known nuclear data for the
  target and other material used in the system
• The need to develop chemical separation and
  partitioning methods that are specific to the
  process in an ADS.

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3. Available ADS and those in the Design Stage

• Because of the mentioned problems, only a few ADS
  are in use or have been designed to some degree
  of details at the present time.
• These are
• The SING facility at the Paul Scherror Institute
  PSI in Villigen, Switzerland, makes uses of the
  590 MeV, 1.5 mA proton beam from PSI cyclotron
  (nth 1013 cm-2 s-1,)
• Russian facility in the Joint Institute for
  Nuclear Research, Dubna, Russia (GeV).
• MYRRHA A multipurpose ADS being developed
  jointly by Belgian Nuclear Research Center and
  Ion Beam Applications 350 MeV, 5 mA proton
  beam.
• The Spallation neutron facility to be built at
  Oakridge National Laboratory ORNL in
  cooperation with several other U.S. national
  laboratories, will have about twice the neutron
  flux in, SING facility
• the European Spallation Neutron Source ESS and
  a Japanese facility with similar design features,
  will have an order of magnitude higher thermal
  neutron flux of SING facility.

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Fig. 1 Schematic View of the Target System
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Fig. 2 Schematic Diagram of a Separate High
Energy Target
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Fig. 3 Scheme of the Target and Fuel Spheres
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Fig. 4 Diagram of a Beam Driven Liquid Cooled
ADS Without Separate Target.
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Fig. 5 Diagram of the Fuel Assembly
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Fig. 6 Diagram of Spherical Fuel Pellets in a
Fluidized Bed Configuration
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Fig. 7 Global view of the present design of MYRRHA
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Fig. 8 MYRRHA in a confinement building that is
inaccessible during operation
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5. Target, Fuel, Coolant and Accelerator Types

• A) Target Types
• Solids or liquids can be used as fuel. The
  requirement for both is high neutron yields and
  for solids they should have high fusion
  temperature
• Lead fusion 327o heavy target is considered
  practical
• Solid Tungsten
• Solid metallic, oxides, nitrides, carbides,
  etc.
• Lead Bismulth liquid targets

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The advantages of liquid metal targets over
volume cooled solid targets

• Higher heat removal capability due to the fact
  that the heated material is transported rather
  than the heat.
• Higher spallation material density in the volume
  due to absence of cooling channels which tend to
  dilute the target the more the higher the power
  density.
• No or minimum amount of water with its associated
  problems in the proton beam.
• No life time limit caused by radiation damage in
  the target material.
• Significantly lower specific radioactivity in the
  target material due to the target mass used and
  perfect mixing, making an emergency cooling
  system unnecessary.
• The inside pressure in the target can be
  significantly lower than in water cooled system,
  putting less stringent requirements on the
  casing wall.

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• B) Fuel Types
• Solids metallic, oxides, nitrides, carbides,
  etc.
• Molten Salt Fluorides or Chlorides
• C) Cooling Agent
• Gas
• Molten Metal Sodium, Lead, or Lead, Bismulth
• Molten Salts Transparent to visible light, and
  thus allow visual inspection
• D) The Accelerator System
• Cyclotron more compact and thus require less
  space and more economical. However there is
  current limitation 5 10 mA.
• LINACS Current ? 100 mA

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• 6. The Physics of Spallation
• The physics of spallation is in fact rather
  complex because of the large range of energies
  involved, and efforts are still going on in
  various locations to develop models that
  reproduce all the pertinent experimental
  observations.
• During the spallation process not only ns but
  also protons and other light nuclei are emitted
  from the excited nuclei. As a consequence, the
  residual nuclei are not only neutronpoor
  isotopes of the parent nucleus that decay, mainly
  by internal p ? n conversion and ? emission,
  into lower Z elements, but these elements are
  also created directly in the spallation process.

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• About 90 of the ns released from thick targets
  in a spallation
• reaction can be described by characteristic
  energies around
• 1 2 MeV and are emitted more or less
  isotopically. Their
• spectral and angular distributions thus resemble
  closely to those
• of fission ns Figure 9 .
• The small fraction cascade ns whose energy can
  reach up to
• that of the primary particles driving the
  reaction, are emitted
• mainly in the forward hemisphere relative to the
  proton beam.
• They are difficult to moderate and thus
  constitute the main
• problem in shielding and activation in a
  spallation neutron
• source.

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Fig. 9 Calculated neutron spectra for fission
and for spallation in a tungsten target
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Fig. 10 Chain of Possible Reactions Starting from
Initial 232Th fuel. Cross Sections are for
Thermal Neutrons in Barns.
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Fig. 11 Time Evolution of the Composition of an
Initial, Thin Thorium Slab Exposed to a Constant
Thermal Neutron Flux of 1.0 x1014 cm-2 s-1.
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Fig. 12 Chain of Possible Reactions Starting from
initial 238U fuel.
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Fig. 13 The Evolution of the Composition of an
Initially Slightly Depleted Uranium Fuel.
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7. Applications of ADSs

• Production of Energy a credible alternative to
  fast breeder and fusion reactors. They give a
  unique opportunity to improve the social
  acceptability of fission energy.
• Nuclear Waste Processing
• Transmutation, which by neutron capture,
  transforms a radioactive nucleus into a stable
  one.
• Incineration which amount to nuclear fission
  following neutron capture transuranic elements
  such as Pu and minor actinides Np, Am, Cn. They
  have high radiotoxicities due to this dominant ?
  decay. They have long lifetimes, up to 25000
  years for 239Pu. At least one incineration
  reactor for four PWRs would be needed if one
  wants to incinerate completely plutonium and
  minor actinides.
• Production of radioisotopes for medical and
  industrial purposes.
• Production of tritium

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8. Conclusion

• It is evident that ADS are now accepted by
  sponsoring agencies and by members of the nuclear
  community as valuable new tools in basic research
  and in applications.
• This will require new technologies of immediate
  relevance for ADS development. A first
  demonstration prototype of several tense of MW
  could be build within 5 7 years.
• An industrial realization would probably require
  at lest 15 years.

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Thank You