Status of US ITER Neutronics Activities Outline Examples of US activities during EDA US ITER neutronics activities in the past year Possible future.
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Status of US ITER Neutronics Activities
Outline
Examples of US activities during EDA
US ITER neutronics activities in the past year
Possible future US contribution to ITER neutronics activities
US Neutronics Computation Capabilities
The US has been developing state-of-the-art computational tools and data bases for nuclear analyses
Most recent versions of codes and data will be used in ITER nuclear analysis:
Transport codes: MCNP5 (Monte Carlo), DANTSYS3.0 (ONEDANT, TWODANT, THREEDANT), DOORS3.2 (ANISN, DORT, TORT)
Activation Codes: ALARA, DKR-Pulsar, REAC
Data Processing Codes: NJOY99.0, TNANSX2.15, AMPX-77
Nuclear Data: ENDF/B-VI, FENDL-2
Sensitivity/Uncertainty analyses: FORSS, UNCER
U.S. has been Active Participant in ITER Nuclear Analysis During CDA and EDA
Examples of US Contribution:
• Nuclear assessment of breeding blanket options and magnet shield optimization during CDA
• Contributed to development of complete integrated MCNP ITER (EDA) model that includes details of shielding blanket modules, divertor cassettes, VV with ports, TF coils, PF coils, CS coils
• Modified MCNP allowing it to sample from actual pointwise neutron source distribution in ITER plasma
• Calculated poloidal neutron wall loading distribution at FW and divertor cassette plasma facing surface
Determined nuclear heating (W/cm3) profiles in divertor cassette
Calculated radiation damage in cassette components
Evaluated adequacy of VV and TF coil shielding by calculating hot spot damage, gas production and insulator dose
Performed 3-D divertor cassette pulsed activation calculations to determine radioactive inventory, decay heat, and radwaste level
Assessed streaming effects
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3-D Nuclear Analysis for Divertor Cassette
Nuclear parameters in waveguides
Streaming through viewing slots
Nuclear parameters in mirror assemblies
Neutronics Assessment of Divertor Diagnostics Cassettes
Cos
Distance from plasma center
2-D R-Modeling of Two Test Modules Placed in Test Port
Two Test modules of the EU Li4SiO4 helium –cooled design are placed in the test model
Edge-on Arrangement
A lattice consists of FS layer (0.8 cm), Be bed layer (4.5 cm) and SB bed layer (1.1 cm)
Buffer zone between modules (10 cm)
Upper module has 75% Li-6 (19 lattices), lower module 25% Li-6 (16 lattices)
Lower attenuation (higher flux) behind beryllium layers
Earlier Work -1996
2-D Model of ITER Building
2-D Model of ITER Machine
Tritium Building 3-D modeling
Dose Rate (S/h) in ITER Building During Operation and After Shut Down
Coupled 2-D and 3-D Calculations using Deterministic method (DORT and TORT codes) for neutron and gamma flux calculations and DKR-Pulsar code for dose calculations
One Week after Shutdown
R-Z model of SS316/Water assembly
R-Z Model of the simulated Super conducting magnet in
SS316/Water Assembly
Verification of ITER Shielding Capability with Various Codes and Nuclear Data
SS=Shelf-shielded data- SS316/water assembly
Participants in this Task:
US/JAERI: for thick shield experiments
EU/RF: for thin shield experiments
Data Verified: Various reaction rates, neutron and gamma spectra, heating rates
US Nuclear Support for ITER Restarted Following US Rejoining ITER in 2003
Major effort has been in support of ITER TBM program
A study was initiated to select two blanket options for US ITER-TBM in light of new R&D results
Initial conclusion of US community is to select two blanket concepts• Helium-cooled solid breeder concept with ferritic steel structure • Dual-Coolant liquid breeder blanket concepts with ultimate potential
for self-cooling– a helium-cooled ferritic structure with self-cooled LiPb breeder
zone that uses SiC insert as MHD and thermal insulator – a helium-cooled ferritic structure with low melting-point molten salt
DEMO
Blanket
ITER
DEMO Blanket Testing in ITERDEMO Blanket Testing in ITER
1. Detailed design of realistic DEMO Blanket
2. DEMO relevant TBM designed
3. TBM inserted for testing in
ITER port
Assessment of Dual Coolant Liquid Breeder Blankets in Support of ITER TBM
Assessment of Dual Coolant Liquid Breeder Blankets in Support of ITER TBM
DC-Molten Salt
DC-PbLi
He Outlet Pipe
He Inlet Pipe
Grid Plates
Back Plate
First Wall
SW/FW He Inlet/Outlet
Manifold
He Flow Inlet Distribution Baffle
LL Flow Outlet Distribution Baffle
3-D Calculation for DC MS 3-D Calculation for DC MS
Be zone Perforated plates
FW Coolant channels
Front Flibe Zone, Flow Direction Poloidal Up
Back FLiBe Zone, Flow Direction Poloidal Down
He Manifold Separator plate,
Cross section in OB blanket at mid-plane
• Total TBR is 1.07 (0.85 OB, 0.22 IB). This is conservative estimate (no breeding in double null divertor covering 12%)
• 3-D modeling and heterogeneity effects resulted in ~6% lower TBR compared to estimate based on 1-D calculations
• Peaking factor of ~3 in damage behind He manifold
Blanket thicknessOB 75 cm (three PbLi channels)IB 52.5 cm (two PbLi channels)
Local TBR is 1.328OB contribution 0.995IB contribution 0.333
If neutron coverage for double null divertor is 12% overall TBR will be ~1.17 excluding breeding in divertor region. To be confirmed by 3-D neutronics
Shield is lifetime component
Manifold and VV are reweldable
Magnet well shielded
Nuclear energy multiplication is 1.136Peak nuclear heating values in OB blanket
o FS 36 W/cm3
o LL 33 W/cm3
o SiC 29 W/cm3
Preliminary Neutronics for DC PbLi BlanketPreliminary Neutronics for DC PbLi Blanket
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Nuclear Heating Rate in the Li4SiO4 BreederWall Load= 0.78 MW/m2
Breeder1 100%
Breeder2 100
Distance from Front Edge, cm
DCPB TBM with Parallel Breeding zones
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Nuclear Heating Rate in the Beryllium Multiplier Wall Load= 0.78 MW/m2
BE Be1 100Be Be2 100Be Be3Be Be4 100
Distance from Front Edge, cm
DCPB TBM with Parallel Breeding zones
NWL 0.78 MW/m2
75% Li-6 enrichmentPacking factor for Be and Li4SiO4 Pebble beds 60%
Two Types of Helium-Cooled SB PB modules under consideration for Testing in ITER
Type 1: Parallel Breeder and Multiplier:
Local TBR: 1.2In Demo Configuration- 1-D
Type 2: Edge-On configuration
Local TBR: 1.04In Demo Configuration- 1-D
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Heating Rate in the Breeding UnitNWL= 0.78 MW/m2 zone 4 Fe 100
zone 4 be 100zone 5 fe 100zone 5 be 100zone 6 fe 100zone 6 be 100zone 7 fe 100zone 7 be 100Br fe 100Br be 100br br 100
Distance from front edge (cm)
Li4SiO4 Breeder
Beryllium
Structure
Neutronics module under evaluation to ensure that design goals are met
Proposed scheme is to evaluate two design configurations simultaneously; however 2-D (3-D) neutronics analysis must be performed to ensure that design goals are met.
Demo Act-alike versus ITER-optimized designs
• Structural fraction: • ~ 23% Demo Vs. ~21% ITER
• Total number of breeder layers/layer thickness:
• 10 layers/13.5 cm Vs. 8 layers/14.9 cm
• Beryllium layer thickness:• 19.1 cm vs. 17.9 cm
• Determine geometrical size requirements such that high spatial resolution for any specific measurement can be achieved in scaled modules
• Allow for complexity, to maximize data for code validation
Goals
2-D R-theta Model developed for DORT discrete ordinates calculations to analyze the nuclear performance of the US two sub-modules with actual surroundings
Close-up radial details
Top View
Details of Theta variation at the Port
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Toroidal Distance from Frame, cm
d (distance from front edge, mm)
d= 0 mm
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d= 21 mm
Left Configuration Right Configuration
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Distance from Frame, cm
Left Configuration Right Configuration
Layer#
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Nuclear Heating in FW of The Two U.S. Test Blanket Configurations in
the Toroidal Direction
Toroidal Profile of Tritium Production Rate in each Breeder Layer of the Two
Test Blanket Configurations
• Profiles are nearly flat over a reasonable distance in the toroidal direction where measurements can be performed with no concern for error due to uncertainty in location definition
• Steepness in profiles near the edges is due to presence of Be layer and reflection from structure in the vertical coolant panels
US Contribution to ITER Nuclear Analysis will be in the following areas:
Nuclear analysis for ITER TBM
Nuclear support for basic ITER Machine
Development of CAD/MCNP interface
Level of effort will depend on availability of funding
US will Contribute to ITER Nuclear AnalysisUS will Contribute to ITER Nuclear Analysis
TBM designs will be developed and modeled for 3-D neutronics calculations with all design details
The TBM 3-D model will be integrated in the complete basic ITER machine 3-D model
Perform 3-D neutronics calculations using the integrated model
Neutronics calculations will provide important nuclear environment parameters (e.g., radiation damage, tritium production, transmutations, radioactivity, decay heat, and nuclear heating profiles in the TBM) that help in analyzing TBM testing results
Nuclear Analysis for TBMNuclear Analysis for TBM
Detailed Nuclear Analysis is Needed for ITER Basic Machine During Design and Construction Phases
Detailed Nuclear Analysis is Needed for ITER Basic Machine During Design and Construction Phases
ITER is still undergoing major design changes
As ITER moves toward construction, more accurate nuclear analysis becomes essential part of final design process
Experience shows that neutronics and radiation environment assessments continue through final design and construction phases of nuclear facilities
– Examples include • TFTR and JET • Spallation Neutron Source
Cryo pump duct
IVV channel Cryo pump
Cryostat
This will include computation of radiation field, radiation shielding, nuclear heating, materials radiation damage, and absorbed dose to insulators and other sensitive components
Three-dimensional neutronics calculations will be performed using MCNP5 and FENDL/MC-2.0
Activation analysis will be planned to support safety assessment of the site-specific issues as needed. This includes calculating radioactive inventory, decay heat, and maintenance dose
Activation calculations will be performed using the state-of-the-art ALARA pulsed activation code along with the FENDL/A-2.0 activation data
Radiation leakage through holes and other penetrations must be fully assessed to establish activation levels for personnel access
Nuclear Analysis for ITER Basic MachineNuclear Analysis for ITER Basic Machine
Neutronics Support for Module 18 of FW/Shield (Baffle)
Neutronics Support for Module 18 of FW/Shield (Baffle)
Module 18
We will provide neutronics support for design and construction of module 18
3-D neutronics calculations using the full ITER model will be performed to determine nuclear heating and radiation damage in components of module 18
ITER diagnostics landscape
Many diagnostics systems will be employed in ITER at upper, equatorial and lower ports
Neutron and gamma fluxes affect diagnostics performance
Determination of radiation environment is essential for estimating shielding requirements for diagnostic components such as insulated cables, windows, fiberoptics and transducers, as well as detectors and their associated electronics
Radiation leakage through penetrations in these diagnostic systems must be fully assessed to establish activation levels in and near diagnostic equipment where frequent access will be necessary
We will coordinate with diagnostics group to provide needed nuclear support
Nuclear Analysis for Diagnostics PortsNuclear Analysis for Diagnostics Ports
Neutronics Support for Heating and CD SystemsNeutronics Support for Heating and CD Systems
Will support Ion Cyclotron and Electron Cyclotron heating and current drive systems
These systems have sensitive components (antennas, RF sources, gyrotrons, insulators, and transmission lines) and neutronics support will be essential to address radiation damage and streaming issues
HV DCSupplies
RF Sources Transmission Lines/Decoupler/Tuning
Eight-strapantenna
ITER ion cyclotron system block diagram
We will coordinate with plasma heating group to provide neutronics support as needed
In FY04, we provided neutronics support to US effort on ITER CS
Concern was that helium embrittlement could be a problem for proposed JK2LB steel conduits (employed in place of Incoloy 908) with deliberate boron additives at some grain boundaries
Concluded that helium embrittlement of JK2LB will not be a problem, even with a 50% B concentration at the grain boundaries
Will continue providing neutronics support as needed to ITER CS
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dpa in JK2LBHe appm in JK2LBH appm in JK2LBHe appm in B
dpa or appm
Radial Location (cm)
Radiation Damage Parameters in JK2LB Alloy of ITER CS Coils
At ITER Midplane0.55 FPY operation0.3 MW.a/m2
Neutronics Support for ITER Central SolenoidNeutronics Support for ITER Central Solenoid
CAD-Based MCNP
Use Sandia’s CGM interface to evaluate CAD directly from MCNP
» CGM provides common interface to multiple CAD engines, including voxel-based models
Benefits:» Dramatically reduce turnaround time from
CAD-based design changes– Identified as key element of ITER Neutronics analysis
strategy» No translation to MCNP geometry commands
– Removes limitation on surface types– Robustness improved by using same engine for CAD and MCNP
– Provides 3rd alternative for CAD-MCNP link» Can handle 3D models not supported in MCNP
Status: prototype using direct CAD query from MCNP Issues/plans:
» (Lack of) speed: 10-30x slower than unmodified MCNP» Key research issue: ray-tracing accelerations (lots of acceleration
techniques possible)» Support for parallel execution (CGM already works in parallel)» Goal: speed comparable to MCNP, but using direct CAD
evaluation
Fusion TechnologyInstitute
CGMACIS Pro/E Voxels
MCNPMCNPNative
Geometry
ARIES-CS Plasma
Parallel Computing Sciences Department
IB
OB
θT
IB OB
θT
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