Status of US ITER Neutronics Activities Outline Examples of US activities during EDA US ITER...

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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

Transcript of Status of US ITER Neutronics Activities Outline Examples of US activities during EDA US ITER...

Page 1: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 2: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 3: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 4: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 5: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

Nuclear parameters in waveguides

Streaming through viewing slots

Nuclear parameters in mirror assemblies

Neutronics Assessment of Divertor Diagnostics Cassettes

Page 6: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 7: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 8: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 9: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 10: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 11: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 12: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 13: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 14: 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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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

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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

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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

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Left Configuration Right Configuration

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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

Page 18: 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 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

Page 19: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 20: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

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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

Page 22: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 23: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

ITER diagnostics landscape

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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

Page 25: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 26: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

Page 27: Status of US ITER Neutronics Activities Outline  Examples of US activities during EDA  US ITER neutronics activities in the past year  Possible future.

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

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