Study on Conceptual Design of Tritium Production Reactor based on ST

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Study on Conceptual Design of Tritium Production
Reactor based on ST

• HE Kaihui HUANG Jinhua
• Division 105 of Southwestern Institute of
  Physics,
• Chengdu, P. R. China
• Tuesday, December 22, 2009

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Contents

• Comparison of tritium production
• Neutronics design of ST-TPR
• Preliminary overall design of ST-TPR
• Conclusion and future work

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Comparison of Tritium Production

• D-T fusion is the most probable solution for
  fusion energy

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Comparison of tritium production facilities
1990US, reference comparison of tritium
production reactors,Fus.technol. Vol 19, 1991
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Tritium Production Approaches

• 1. Nuclear reaction in nature
• 2. Nuclear explosion
• 3. Fission reactor
• Heavy-water reactor
• Light-water reactor
• 4. Accelerator production tritium
• 5. Breeding zone in fusion reactor.

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Advantages of APT

• l      No fissile materials
• l        No spent nuclear fuel produced
• l        Produces very little low-level and no
  high-level radioactive
• waste per year
• l        No chance of a criticality accident
• l        Minimal environmental effects
• l        No nuclear proliferation issues
• l        Engineering simplicity provides inherent
  safety advantages
• l        Constant extraction of tritium
• l        Immediate shutdown
• l        Easily scaled to stockpile needs

Disadvantage too expensive, high up to 910B
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Gaps between requirements and state-of-the-arts
for APT
ESS European Spallation Source
Scientists predicted that the time scale for the
APT technology development is 20 years,
comparable to that for a fusion-based tritium
production development. However, as an
alternative approach to producing tritium,
whether APT can be decided as the better one
depends on the development of both technologies.

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Advantages of fusion-based tritium production

• As an intermediate application of fusion energy,
  fusion-based neutron source (NS) is highly
  recommended to develop, so as to contribute to
  fusion science and technology development.
• Compared with Accelerator-based NS, a localized
  source, fusion-based NS is volumetric source with
  a large surface area available for locating
  tritium production assemblies in high neutron
  flux, and has much greater high-neutron-flux
  irradiation volume. Another sequence is that the
  max. neutron radiation damage rate to the FW
  material will be much less for a distributed
  fusion source.
• Development of the vast majority of the physics
  and technology needed for a fusion NS has been
  carried forward as an international
  collaboration in support of ITER, whereas the
  accelerator development would require a
  substantial addition RD program sole for tritium
  production
• Experience gained from fusion-based NS seems to
  have broader application for final fusion energy
  development
• Tritium cost is significantly lower than that
  from APT

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Preliminary design of ST-TPR
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Neutronics design of ST-TPR
Neutronics codes flow in calculation

• Tremendous work in codescodes update, database
  check, benchmark calculation,error analysis and
  explanation.
• 1D results as Reference for design 2D results as
  design point.
• Tritium production objective 1kg/a with
  availability 40

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Neutronics design for ST-TPR
Major dimension consideration,gross tritium
product per year
Except fusion fuel cycle, leakage, etc., net
tritium
Set neutron wall loading,?n1.0MW/m2,plant
factor,PF40,the relationship between blanket
first wall radius rin,rout and TBR for 1kg excess
tritium production
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Neutronics design for ST-TPR

• Plasma core consideration for 1kg/a excess
  tritium production
• The tritium consumption by the fusion neutron
  source is 5.6?PF kg/a per 100MW of fusion power.

Initial tritium inventory is not included

• For production of 1kg/a excess tritium,if
  PF?0.4, actually 3.24kg /a is produced for
  fusion power 100MW.

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1D neutronics calculation model

• Zones included and material compositions for 1D
  calculation
• Center post,ie, CS,material Al,he-4(coolant)
• Inboard shield,SS316,B4C,and He
• Inboard V.V.,SS316 and He
• Inboard tritium production blanket,TRITIUM
  BREEDER 6Li(enrichment 92) and 7Li NEUTRON
  MULTIPLIER Be,SS316 and He
• Inboard First Wall,Be, He and SS316
• Inner SOL
• Plasma zone
• Outside SOL
• Outboard First Wall,material similar as inboard
  first wall
• Outboard tritium production blanket, main TPB,
  material similar as inboard TPB, different
  fractions
• Outside V.V., SS316 and He
• Outboard shield,main shield, SS316,B4C,and He.

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option 1 for neutronics calculation

• Tritium was produced only in outboard TPB, which
  was divided 2 zones for both neutron multiply and
  tritium breed, respectively.

R 0 32.0 33 40.0 264.
270. 271 272.5 280 281.5 315. 318. 320.
340. 360. XINTS 16 2 7 100
6 2 3 15 3
67 6 2 10 10
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TBR from option 1

• 1?Effects of Be/Li zones thickness in outboard
  TPB on TBR

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TBR from option 1

• Results for case 1
• TBR is not so high as expected (max. 1.65) when
  outboard tritium production blanket is divided
  into 2 zones for neutron multiply and tritium
  breeding, respectively. then it is not good
  solution for tritium production.
• The thicker Be zone,the smaller TBRseemly
  inverse as expected,The thinner Be zone, the
  bigger TBR.
• In blanket design specially for tritium
  production, the division scheme of blanket into
  neutron multiply and tritium breeding zones is
  not good consideration with respect to high TBR.

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option 1 for neutronics calculation
2. Effects of blanket thickness on TBR

• The TBR is not large for all blanket thickness
  from 10cm to 60cm When outboard blanket is
  divided into two zone for neutron multiplying and
  tritium breeding,respectively. The max. TBR is
  about 1.7, taken 2D and 3D effects into account,
  it is not ideal solution for tritium production.

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option 2 for neutronics calculation

• Tritium is only produced in outboard blanket,
  which is not divided into 2 main zones,
• investigate the effects of TPB thickness and
  Be/Li volume fraction on TBR.

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TBR from option 2

• 1?dependence of TBR on Be/Li fraction (total
  70) In blanket

• Choose Be/Li is 0.6/0.1,TBR of 6Li is maximum,up
  to 1.85?
• This option requires that the volume of Be is
  large,while that of Li is small, Li breeder is
  distributed among Be block

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TBR from option 2 contd

• 2?dependence of TBR on Blanket thickness

• TBR increases with blanket thickness, 47cm is
  chosen for design value,
• corresponding TBR is 1.98(1D),the contribution
  of 6Li is 1.958

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option 3 for neutronics calculation

• Tritium is produced in both inboard and outboard
  blanket, and
• an anti-leakage blanket is located outside
  divertor. This scheme
• is called three surrounding blankets for tritium
  production
• 1D neutronic calculation for TBR is 1.9, the
  contribution of anti-leakage blanket outside
  divertor is not included?Then 2D calculation is
  carried out.

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option 3 contd
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option 3 contd
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option 3 contd
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Results from option 3
2D neutronics calculation
Corresponding 1D neutronics calculation
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Results from option 3 contd

• We can see
• Total TBR from 2D neutron calculation is 1.682,
  while 1.928 from 1D calculation.
• TBR from 2D neutronics calculation is smaller
  than that from 1D calculation because neutron
  leakage depends on the model chosen for
  calculation.
• The contribution to TBR from inboard blanket is
  less than 0.1 (total 1.682), the majority of TBR
  is from outboard tritium production blanket.
• We chose this optimal scheme for our design one.

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ST-TPR design

• ST-TPR ST-based Tritium Production Reactor
• TTPR Tokamak Tritium production Reactor

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ST-TPR Design Parameters
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ST-TPR design

• Magnet system
• common magnets used in ST-TPR ,the max. operating
  magnetic B?22.5T ,which can be developed and
  investigated in MAST and NSTX experiments.
• Plasma heating and current driven
• Four types of plasma heating system were
  considered for ST-TPR
• 1) Neutral Beam Injection(NBI)
• 2) Ion cyclotron resonance frequency
  heating(ICRH)
• 3) electron cyclotron resonance frequency
  heating(ECRH)and
• 4) Low hybrid resonance frequency heating(LHRH)
• ICRH was rejected because neutron absorption in
  antennas degraded TBR,
• The heating and Non-inducted current drive
  requirements for ST-TPR
• 5MW of 1.3MeV NBI, 10MW of 5GHz LHRH and 5MW of
  140-170 GHz ECRH.
• Systems with these capabilities are being
  developed in ITER, NSTX?MAST.

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ST-TPR blanket parameters
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Horizontal cross-section schematic of outboard
blanket of ST-TPR (part)
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Amplified small zone of outboard Blanket module
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Temperature distribution of ST-TPR First Wall
5mm Be
10mm SS316
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Shielding layer of ST-TPR
Horizontal cross-section schematic of shielding
layer of ST-TPR
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Development risks, Uncertainties and backup
options

• 1. Plasma physicsthe enhancement of energy
  confinement,H
• The plasma operating parameters of ST-TPR design
  is based on intermediate
• advanced tokamak mode.the main question is the
  enhancement of energy confine-
• ment relative to an empirical scaling law. The
  enhancement of H?2 was designed
• for ITER-FEAT, ST-TPR specifies H2.5, if it can
  not be achieved, we can
• increasing plasma current to compensate a
  shortfall of H factor, and
• Increasing auxiliary heating power to compensate
  the shortfall of H factor.
• 2. heating and current drive systems
• The three auxiliary heating/ current drive
  systems in ST-TPR concept are all
• extension of present technology under ITER-FEAT,
  if one of them runs into
• difficulty, it should compensate by other
  systems, then much attention should be
• paid to achieving the driven current profiles
  required for the advanced tokamak
• modes.

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Development risks, Uncertainties and backup
options

• 3. Material problems
• Structural materialSS316much larger database
  and experience base in radiation environment.
• Backup options
• Ferritic Steel, FeS, has better thermo-mechanical
  and radiation-resistant properties and has larger
  international development program than V-4Ti-4Cr.
• Tritium-producing material
• A substantial program for the development
  of17Li-83Pb eutectic in Europe
• A substantial development program for ceramic
  lithium-containing materials for tritium
  production in Japan and Europe, eg. Li2O
• Lithium (6Li enrichment 92) is specified as
  tritium breeding material.

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Development risks, Uncertainties and backup
options

• 4. Design details the devil is in the details
• We tried to be realistic and to err on the side
  of conservatism in assumption in ST-TPR design,
  it is inevitable that a more detailed design
  would result in a less optimistic assessment of
  tritium production capability.
• 3D effects was not considered in TBR, which will
  lead to lower result.
• As for reliability and plant factor, 40 is
  needed to achieve its tritium production
  objective, however, during initial operation,
  this factor can not met. With the development of
  plasma science and engineering technology, the
  objective can be achieved and surpassed.

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Conclusion and future work

• Tritium production comparison was performed for
  optimal approach
• Neutronics calculation was conducted for ST-based
  Tritium Production Reactor,ST-TPR, the TBR
  obtained is up to 1.682.
• Based on TBR optimal design, overall design of
  ST-TPR, which can produce 1kg/a tritium with PF
  approx. 40, was carried out preliminarily.
• As a pre-conceptual design, numerous
  uncertainties, risks and backups are discussed.
  Much work should be continued.

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• Thank you!