fusion neutronics activities in usa reported for the neutronics groups at ucla, uw, and tsi...
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Fusion Neutronics Activities in USAReported for the Neutronics Groups at
UCLA, UW, and TSI Research, Inc.
byE.T. Cheng
TSI Research, Inc.P.O. Box 2754
Rancho Santa Fe, CA 92067U.S.A.
Workshop on Sub-Task Fusion Neutronics under IEA Implementing Agreement on a Co-operative
Program on the Nuclear Technology of Fusion Reactors
21 September 2004 (SOFT)Venice, Italy
Fusion Neutronics Activities at the University of Wisconsin at Madison
• Neutronics Analysis in Support of ITER Test Blanket Modules– Assessment of Dual Coolant Liquid Breeder
Blankets, Molten Salts and PbLi– Three Dimensional Modeling and Calculations
• Development of CAD-based MCNP
• Development of Activation Code, ALARA– Availability: Distribution by RSICC (ORNL)
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 regionShield 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
Parallel Computing Sciences Department
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
» 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
Clothespin, w/helical spring surface
Activation Code Development
• ALARA - Version 2.7 available for use– Exact modeling of pulsed/intermittent sources– “Reverse” mode for efficient calculation of rare products– Direct calculation of:
• Waste disposal rating• Contact dose
• Total shutdown heating• Biological dose (requires source-to-
dose adjoint calc)
– Continuing development:• Sequential charged particle reactions• More data format/type support
• Monte Carlo activation code under development
alara.engr.wisc.eduwilsonp@engr.wisc.edu
Relative difference between EAF and IEAF decay heat calculations in IFMIF HFTM
Fusion TechnologyInstitute
Fusion Neutronics Activities at the University of California at Los Angeles
• Neutronics Analysis in Support of ITER Test Blanket Modules– Activation Analysis of Dual Coolant Molten
Salt Liquid Blankets– Design Analysis of Solid Breeder, Pebble-Bed
Test Blanket Modules– Two Dimensional Discrete-Ordinates Code,
DORT
Comparison Between Total Activity and Decay Heat in Each
Material in the Flibe and Flinabe Dual Coolant Blankets
10-5
10-4
10-3
10-2
10-1
100
101
102
103
104
105
10-1
100
101
102
103
104
105
106
107
108
109
1010
1011
F82H (Flinabe Breeder)
Flinabe with tritium
Be (Flinabe Breeder)
F82H (Flibe Breeder)
Flibe with tritium
Be (Flibe Breeder)
Time after Shutdown, sec
1 s 1 m 1 h 1 d 1 mo 1 y 10 y 100 y 1000 y
Total in 8.3-m long Inboard and Outboard Modules
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
100
101
102
103
10-1 100 101 102 103 104 105 106 107 108 10910101011
F82H (Flinabe Breeder)Flinabe with tritiumBe (Flinabe Breeder)F82H (Flibe Breeder)Flibe with tritiumBe (Flibe Breeder)
Time after Shutdown, Sec
1 s 1 m 1 h 1 d 1 mo 1 y 10 y 100 y 1000 y
Total in 8.3-m long Inboard and Outboard Modules
•The activity generated in Flibe is larger than in Flinabe by a factor of 1.5-2 in the time frame of few days to few years after shutdown. However, there is an appreciable contribution to the total decay heat in Flinabe that is attributed to the generation of Na-24, up to few hours, and to the production of Na-22 up to several years following shutdown.
0.1
1
10
0 10 20 30 40 50
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
0.1
1
10
0 10 20 30 40 50
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
0.1
1
10
0 10 20 30 40 50
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
• To determine geometrical size requirements such that high spatial resolution for any specific measurement can be achieved in scaled modules
• To allow for complexity, to maximize data for code validation
Goals
Top View of the U.S. and Japan Test Blanket Modules Placed in a ½ Port in ITER
2-D R-theta Neutronics Calculation to Analyze the Nuclear Performance of the US TBM with Actual Surroundings
Calculation Model
Calculation by DORT-Discrete Ordinates Transport Code, 46 neutron-21 gamma groups
6.5
7
7.5
8
8.5
9
9.5
0 10 20 30 40 50 60 70
Toroidal Distance from Frame, cm
d (distance from front edge, mm)
d= 0 mm
d= 10.5 mm
d= 21 mm
Left Configuration Right Configuration
Nuclear Heating in the First Wall of the Two U.S. Test Blanket Configurations in the Toroidal Direction
•Toroidal heating rate is nearly flat over a distance of ~10-14 cm (left Config.) and ~16-20 cm (right Config.)
• Heating rate measurements could be performed over these flat regions with no concern for error due to uncertainty in location definition
Toroidal Profile of Tritium Production Rate (TPR) in each Breeder Layer of the Two Test Blanket Configurations
•Profiles of the TPR is nearly flat over a reasonable distance in the toroidal direction where measurements can be performed (10-16 cm in the left Config. and 10-20 cm in the right Config.).
•Steepness in the profiles near the ends is due to presence of Be layer and reflection from structure in the vertical coolant panels (VCP). This is more pronounced at the outer VCP.
0
1 10-5
2 10-5
3 10-5
4 10-5
5 10-5
0 10 20 30 40 50 60 70
Distance from Frame, cm
Left Configuration Right Configuration
Layer#
Layer#
1
2
3
4
5
6
7
8
9
1
3
2
4
5
6
3
Fusion Research and Neutronics Activities at TSI Research, Inc.
• Application of Fusion Neutrons– Transmutation of Spent Fuel Actinides – U238 Burning Power Plants– Performance of Sub-criticality of Actinides in
Equilibrium in Fusion Blankets
• Nuclear Data for Fusion– Nuclear Data Needs Activities– Review of Helium Generation Data for IFMIF (ANLNDM-158, by Donald L. Smith)
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