Laser Direct Manufacturing of Nuclear
Power Components
Dr. Jyotsna Iyer, Dr. Scott Anderson, Gautham Ramachandran,
Georgina Baca, Scott Heise, Dr. Slade Gardner
3 November 2014
Acknowledgment: “This material is based upon work supported by the Department of Energy , Office of Nuclear Energy,
Idaho Operations, under Award Number DE-NE0000542”
Disclaimer: “This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States
Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for
the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe
privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise
does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views
and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.”
Nuclear Energy in the U.S.
– 4 new plants under construction in U.S., >60
globally, >150 on order
• Current Light Water Reactors (LWR) cost $10B$12B/unit
– Costly on-site construction
300
Gigawatts -electric
• 104 reactors in the U.S. providing 20% of our
electricity
200
100
0
2010
2020
2030
2040
2050
Current reactors, 40 years
Current reactors, 60 years
New capacity being considered
4 Builds per year starting 2021
Generating capacity with 80-year life
• Next generation Small Modular Reactors (SMR)
estimated $800M-$2B/unit
– DOE SMR program funding ~$400M
– B&W and NuScale selected for concept development
– Factory fabrication, rapid installation
• Advanced materials and manufacturing are
significant industry drivers
Advanced/Affordable Manufacturing methods are key enablers for
competing in $700B global market
2
DOE Nuclear Energy Enabling Technologies (NEET)
Advanced Manufacturing Methods (AMM)
Contract: DE-NE0000542
POP: 36 months, GFY13 - GFY15
DOE Team: Alison Hahn (HQ), Jack Lance (HQ), Bradley Heath
(HQ)
LM Team: Gautham Ramachandran, Dr. Scott Anderson, Dr.
Jyotsna Iyer, Georgina Baca, Scott Heise, Dr. Slade Gardner
Dr. Eric Faierson, Quad City Manufacturing Laboratory
Scope
Purpose: Position U.S. to compete in $B
international market for nuclear power via enabling
technology that significantly reduces development
and operational costs and manufacturing lead time
for nuclear reactors
Project Objectives: Demonstrate >50% cost and
schedule reduction using additive manufacturing
methods. Develop, advanced radiation tolerant
alloys via nanophase modification during additive
manufacturing for reduced life cycle costs.
HIGHLIGHTS
LM CE&T Energy IPT funding costshare and supporting industry
engagement and growth opportunities
Net-Shape Manufacturing Demo
Articles built in <18 hours, no
assembly/joining required –
Fuel rod spacer grids manufactured
using 316L SS and Inconel600
Laser Melting
Sintered
powder
Technical Approach
• Build manufacturing demonstrations of complex
parts demonstrating design flexibility and
shortened design-to-manufacturing cycles
• Employ nanophase alloy modification via Laser
Direct Manufacturing (LDM) to create enhanced
radiation tolerance in the components
• Demonstrate the cost and schedule benefits
through case studies and business case analyses
(Unsintered powder)
Completed Layer
Background for Alternate Nuclear
Materials Selection
Fuel Assembly
1400
Fuel Rod
Cutaway
Very High Temperature Reactor
1200
Fuel
Pellets
Superficial-Water-Cooled Reactor
Fuel
rod
Gas Fast Reactor
100
Lead fast Reactor
Clad
Molten Salt Reactor
Temperature (°C)
800
Spacer
grid
600
400
Fuel
pellet
Sodium Fast Reactor
Generations II-III
200
UO2
MOX
0
0
50
100
150
200
Displacements Per Atom (dpa)
N13137-01
N13137-02
Water flow
4
Table of Comparison Criteria for Selection
of Alternative Nuclear Materials
Comparison criteria
• Low neutron absorption
• Elevated temperature mechanical
properties
– Creep resistance
– Long-term stability
– Compatibility with reactor
coolant
• Resistance to irradiation-induced
damage (greater than 200 dpa)
–Radiation hardening and
embrittlement
–Void swelling
–Creep
–Helium-induced embrittlement
–Phase instabilities
Alternate Nuclear Materials
• BASELINE: Traditional ferritic/martensitic
steels (HT-9) or later generations of F/M
steels
• OPTION 1: ODS steels to examine effect of
direct manufacturing methods on
nanoscale oxide domains
• OPTION 2: Inconel 800 series of materials
to study the effect of processing
parameters offered by direct
manufacturing methods to improve
performance under irradiation
• OPTION 3: Among the refractory alloys,
the Mo (TZM) alloys. These have a high
operating temperature window and also,
the most information on irradiated
material properties
Based on customer feedback at Technical review, materials down-selected
to 316SS, ODS steels and Inconel alloys
5
Material Down selection for DM
Demonstration
• Alloys: Inconel 600, Inconel 718, Incoloy 800, 316L SS, ODS Steels
• Oxides: Yttrium, Cerium - Mix of nano- & micron- sized oxide particles
selected for mixing
10 x 10 Grid
10 x 10 Grid
3 x 3 Grid
Emerging literature in Austenitic ODS alloys
• Development of Austenitic ODS Strengthened Alloys for Very High Temperature Applications
(http://energy.gov/sites/prod/files/2013/09/f2/Stubbins_Austenitic%20ODS%20NEUP.pdf)
• Synthesis and Characterization of Austenitic ODS alloys (http://www.mme.iitm.ac.in/murty/?q=node/96)
6
Process Parameter Variation During
Part Fabrication – Inconel 600
Specimen size Scan speed
Inconel 600 1cmX2cmX1cm 1100mm/s
Inconle 718 1cmX2cmX1cm 1200mm/s
1cmX2cmX1cm
1cmX2cmX1cm
1cmX2cmX1cm
1cmX2cmX1cm
1cmX2cmX1cm
1000mm/s
900mm/s
800mm/s
1200mm/s
1400mm/s
Laser power
195W
195W
Standard EOS
Standard EOS
195W
195W
195W
195W
195W
165W
165W
165W
165W
165W
180W
180W
180W
180W
180W
150W
150W
150W
150W
150W
7
Process Parameter Effect on Fabricated
Part Density – Inconel 600
Laser power of 195W makes the fabricated article almost
insensitive to scan speed
8
Process Parameter Effect on Fabricated
Part Density – Inconel 718
Laser power of 165W most consistent for Inconel 718; more
scatter in density data
9
Microstructure Characterization
Sample #
Sample name
Micrograph (100X)
Density (g/cm3)
Proces Parameters
Notes:
Power (W) Speed (mm/s)



4
600_150_1400
8.235
150
1400
10
600_180_1400
8.299
180
1400
11
600_195_800
8.384
195
800
12 (a)
600_195_1100
8.37
195
1100
Sample #12 was selected to be
mounted in both the x-y & Z planes
(long)
12 (b)
600_195_1100
8.37
195
1100
Sample #12 was selected to be
mounted in both the x-y & Z planes
(trans)

14
600_195_1400
8.346
195
1400
QCML manufactured 56 of Inconel 600
samples
Fourteen were selected
Five samples were selected for
microstructure characterization
Sample #12 was selected for mounting
in both the x-y & z directions for a total
of six samples
Metallography Procedure
 Mount/ grind/ polish
 Micrograph (photographs)
 Scanning Electron Microscopy
(SEM)
 Etch
 Micrograph
 SEM
Samples produced at the higher
speed rate and lower power
demonstrate more voiding
based micrographs
10
Backscattered Electron Imaging of Sample
600-195-1400
Top
Bottom
Middle
• BSE imaging revealed the solidification/grain microstructure
• Microstructure appeared similar in the three locations examined
• No titanium nitride particles were detected (titanium nitride particles are typically
found in wrought material)
• Black areas in images are voids
11
Microstructure Comparison of Inconel
600 Bar Stock Sample vs Additive
Manufactured Sample
• QCML manufactured 56 of Inconel 600 samples
• Fourteen were selected
• Five samples were selected for microstructure characterization
Metallography procedure
•
•
•
•
•
•
Inconel 600: Bar Stock Sample
500X BSE 10kV not etched
Mount/ grind/ polish
Micrograph
(photographs)
Scanning Electron
Microscopy (SEM)
Etch
Micrograph
SEM
Inconel 600: Sample 500X BSE 10kV
not etched
Noticeable Grain Structure differences due to manufacturing process
12
Examination of Microstructure of Edge Transition
Top Edge: Terminating Side
(a)
(b) Top
Edge:500X
Terminating Side
Side
(c) Top Edge
Transition:
500X
Initiating Side
Side
a) Inconel 600 Micrographs show (b) top edge (c)
transitions (d) interior of sample at 500X
(d) Away
from edge:
500X
13
Test Coupons Ready for Mechanical
Testing
Inconel 600 longitudinal, transverse, and
45deg specimen blanks after LDM
• This build layout
produces 45 test
coupons in a single
build at 1100mm/s
and 195W
• The test coupons are
cylinders with 0.5"
diameter by 3"
length.
• 15 cylinders are in
horizontal orientation
• 15 cylinders are in
vertical orientation
• 15 cylinders are at 45
degrees with respect
to the horizontal.
Samples heat treated (900C for 1-2hr) to remove
after fabrication to prevent warping
14
Next Steps
• Mechanical & microstructural characterization of test
coupons for Alloy 600
• Test specimen build for Alloy 718, Alloy 800
• Characterization of Alloy 718 & Alloy 800 test specimens
• Test coupon build for Alloy 718 & Alloy 800
• Mechanical & microstructural characterization of test
coupons for Alloy 718 & Alloy 800
• ODS steel mechanical blending & trial runs
15
Back up slides
16
Metallurgy of AM Technologies
• Weldable alloys are readily manufactured via AM
– Titanium alloys, stainless steels, alloy/tool steels, nickelbased alloys (Inconel), cobalt-based alloys
• Enables unique control of microstructure
– Very fine grain sizes due to high solidification rates
– Can produce microstructures not possible using conventional
manufacturing methods
• Equivalent or superior mechanical properties to
wrought alloys
17
Material Down Selection for DM
Demonstration
Alloy
Inconel 600
Inconel 690
Procurement Status
250lbs in-house
Inconel 718
Inconel 625
250lbs in-house
Incoloy 800
Incoloy 800H
Purchased from Carpenter expected ship date 9/17
316 SS
316Ti SS
316L SS
304 SS
ODS Steels
T91
In-house
Correct particle size not
available
Oxide list downselected further details being worked
out
•
Mix of nano- and micron- sized oxide particles
selected for mixing with 316SS
Emerging literature in Austenitic ODS alloys
• Development of Austenitic ODS Strengthened
Alloys for Very High Temperature Applications
(http://energy.gov/sites/prod/files/2013/09/f2/Stubbins_Au
stenitic%20ODS%20NEUP.pdf)
•
Synthesis and Characterization of Austenitic ODS
alloys (http://www.mme.iitm.ac.in/murty/?q=node/96)
18
Literature Notes for Austenitic ODS
Steel Composition
• (http://energy.gov/sites/prod/files/2013/09/f2/Stubbins_Austenitic%20
ODS%20NEUP.pdf)
19
Preliminary Examination of 600-195-1400; Mt 14.046
•
•
SPACE SYSTEMS COMPANY
Several Inconel 600 samples were metallographically cross-sectioned and polished
Examination of microstructure on sample 600-195-1400 was conducted using
backscattered electron imaging (BSE)
 Sample was not yet etched
 BSE images were taken in the three locations shown below
Optical Image of Polished Cross-Section
Sample 600-195-1400
Top
Mid
Bot
Mt 14.046
8-7-14 JAB STAR Labs
~ 1cm
20