Transcript The Materials Test Station Eric Pitcher Los Alamos National Laboratory Presentation to: AHIPA Workshop, Fermilab October 19, 2009

The Materials Test Station
Eric Pitcher
Los Alamos National Laboratory
Presentation to:
AHIPA Workshop, Fermilab
October 19, 2009
The MTS will be a fast spectrum fuel and
materials irradiation testing facility
• MTS will be driven by a
1-MW proton beam
delivered by the
LANSCE accelerator
• Spallation reactions produce
1017 neutrons per second
fuel module
target module
beam mask
backstop
AHIPA Workshop, Fermilab, October 19, 2009
The MTS design includes all the services needed
to maintain the target and change out samples
•
•
•
Beam raster system paints
uniform beam spot on target
Independent fuel rodlet and
sample can removal allows
for short or long term
irradiations
target
chamber
service
cell
shield wall
beamline
shield
Irradiated samples are
transferred to shipping casks
in service cell
raster magnets
AHIPA Workshop, Fermilab, October 19, 2009
The MTS target consists of two spallation target
sections separated by a “flux trap”
materials
tungsten
test fuel
sample
spallation
rodlets
canstarget
• Neutrons generated through
spallation reactions in tungsten
• 2-cm-wide flux trap that fits 40
rodlets
Beam pulse structure:
750 µs
7.6 ms
12 cm
16.7 mA
Delivered to: left
target
right
target
left
target
right
target
AHIPA Workshop, Fermilab, October 19, 2009
2 cm
The rastered beam provides nearly uniform
current density over a 60 mm x 15 mm beam spot
Proton Beamlet
3 mm FWHM
horizontal
8 mm FWHM
vertical
Vertical slew
covers 60 mm
nominal spot
height in 750
sec macropulse
Normalized Spot Intensity
15 mm
nominal
spot width
21 mm wide
target face
15 mm Nominal Spot Width
3 mm FWHM Beamlet
(0.01% of protons outside 21 mm)
-12
-10
-8
-6
-4
-2
0
2
4
Target X (mm)
Fast raster is 20kHz sinusoid plus 8.8% 60kHz to make it more
sawtooth shaped. Subsequent macropulses arrive at a different
temporal phase, smearing the average spot vertically.
AHIPA Workshop, Fermilab, October 19, 2009
6
8
10
12
Horizontal cut through the target assembly at
target mid-plane (magnified)
AHIPA Workshop, Fermilab, October 19, 2009
Horizontal cut through the MTS target assembly
at beam centerline – MCNP(X) model
reflector
7 cm
proton beam
spallation target
mask
fuel samples
proton beam
spallation target
materials samples
reflector
AHIPA Workshop, Fermilab, October 19, 2009
backstop
materials samples
Spatial distribution of the proton flux shows low
proton contamination in the irradiation regions
AHIPA Workshop, Fermilab, October 19, 2009
Spatial distribution of the fast neutron flux shows
uniformity over the dimensions of a fuel pellet
Fast (E>0.1 MeV) neutron flux
AHIPA Workshop, Fermilab, October 19, 2009
The neutron spectrum in MTS is similar to that of a fast
reactor, with the addition of a high-energy tail
1
normalized lethargy flux (a.u.)
MTS, upstream rodlet
MTS, peak flux rodlet
MTS, dow nstream rodlet
fast reactor (ABTR)
0.1
0.01
p
0.001
0.0001
0.001
0.01
0.1
1
10
100
1000
neutron energy (MeV)
AHIPA Workshop, Fermilab, October 19, 2009
MTS flux level is one-third to half of the world’s
most intense research fast reactors
Facility
Peak Fast Flux
(1015 n/cm2/s)
Peak Annual
Fast Fluence*
(1022 n/cm2/y)
Peak Annual
Displacement
Rate* (dpa/y)
MTS
(USA)
1.3
2.1
17
BOR-60
(Russia)
2.8
4.6
24
JOYO
(Japan)
4.0
6.9
36
*Accounts for facility availability.
AHIPA Workshop, Fermilab, October 19, 2009
Many MTS characteristics are substantially
similar to a fast reactor
• Same fission rate for fissile isotopes
– For many fuel compositions the burnup evolution (actinide and
fission product concentrations) is nearly the same
• Uniform fission rate throughout the fuel pellet or slug
• Clad irradiation temperature up to 550°C
• Same radial temperature profile for a given linear heat
generation rate and pellet/slug radius
• Same burnup-to-dpa ratio
AHIPA Workshop, Fermilab, October 19, 2009
Principal differences between MTS and a fast
reactor
• High-energy tail of neutron spectrum
• Pulsed nature of the neutron flux
• Beam trips
AHIPA Workshop, Fermilab, October 19, 2009
High-energy tail of neutron spectrum produces
differences from fast reactor irradiations
• Higher helium production in steels
– Known to embrittle austenitic steels operating above 0.5 Tm
– Effect on ferritic/martensitic steels not yet well understood
– 0.5 Tm is 550°C for SS316, 610°C for T91
• Higher helium production in
Gas Production Comparison in MOX to 10% burnup
oxide fuels from O(n,α) reactions
• Higher Np production in fertile
fuel from
238U(n,2n)
reaction
Xe
7.0E-04
Kr
6.0E-04
atoms/b-cm
– He production 2x greater than
ABTR, but total gas production
is only 10% greater
8.0E-04
He
5.0E-04
4.0E-04
3.0E-04
2.0E-04
1.0E-04
0.0E+00
ABTR
AHIPA Workshop, Fermilab, October 19, 2009
PWR
MTS
Pulsed neutron flux issues
• Temporal peak of the neutron flux is inversely
proportional to the beam duty factor (7.5%)
• Beam pulse repetition rate is 100 Hz
– For oxide fuel, thermal cycling is not significant because thermal
time constant (~100 ms) is much longer than the time between
pulses (~10 ms)
– Metal fuels may exhibit thermal cycling in MTS
• Studies show that 100 Hz is nearly equivalent to steadystate with respect to bubble nucleation in steels
AHIPA Workshop, Fermilab, October 19, 2009
Accelerator beam trips are a potential issue for
oxide fuel irradiation in MTS
• Normal reactor conditions:
FRESH FUEL (OUT OF CORE)
– On startup, thermal stresses
crack oxide pellets
– Cracks in the columnar grain
region heal during reactor
operation
– When reactor is shut down,
pellets re-crack
FRESH FUEL
(ON STARTUP)
10 MWD/MT
(IN CORE)
• The LANSCE accelerator will trip
10 MWD/MT
(OUT OF CORE)
several times each day, during
which the fuel temp drops to
~300°C
– Cracks in the columnar grain
region likely will not have time to
fully heal between thermal
cycles
100 MWD/MT
(IN CORE)
1 GWD/MT (IN CORE)
AHIPA Workshop, Fermilab, October 19, 2009
The MTS neutron spectrum has potential
application for fusion materials research
1016
MTS (400 cm3)
IFMIF HFTM* (500 cm 3)
ITER first w all*
neutron flux (n.cm–2.s–1.MeV–1)
1015
1014
1013
1012
1011
1010
109
0.001
0.01
0.1
1
10
100
neutron energy (MeV)
* Data from U. Fischer et al., Fusion Engineering and Design 63-64 (2002) 493-500.
AHIPA Workshop, Fermilab, October 19, 2009
1000
The damage rates for the MTS approach those
observed in IFMIF and are 3 times ITER
ITER 1st wall
IFMIF HFTM (500 cc)
MTS (400 cc, fuel module)
IFMIF Li back wall
MTS (peak, fuel module)
appm He/FPY*
114
319
266
619
393
dpa/FPY*
10.6
25.6
24.9
65.8
33.9
He/dpa
10.8
12.5
10.7
9.4
11.6
*FPY = full power year; MTS expected operation is 4400 hrs per year.
Values for MTS assume 1 MW of beam power.
300
250
30
dpa per FPY (cumulative, 0 to E)
appm He per FPY (cumulative, 0 to E)
350
MTS
IFMIF
ITER 1st w all
200
150
100
50
0
0.1
1
10
E (MeV)
100
1000
25
20
MTS
IFMIF
ITER 1st w all
15
10
5
0
0.1
1
AHIPA Workshop, Fermilab, October 19, 2009
10
E (MeV)
100
1000
At 1.8 MW, MTS provides nearly the same dose
and irradiation volume as IFMIF
MTS beam power = 1.8 MW
MTS beam power = 1 MW
60
60
IFMIF HFTM
IFMIF HFTM
50
minimum dpa in Fe/FPY
minimum dpa in Fe/FPY
50
40
30
MTS - fuel module
20
MTS - fuel module
40
30
20
MTS - material modules
10
10
MTS - material modules
0
0
100
200
300
400
500
600
700
0
0
100
200
irradiation volume (cm3)
AHIPA Workshop, Fermilab, October 19, 2009
300
400
500
irradiation volume (cm3)
600
700
MTS project status
• In November 2007, DOE-NE approved CD-0 for a “Fast
Neutron Test Capability.” MTS was one of three
alternatives identified to meet the need
• In FY10 , MTS project expects to submit its CD-1
package for approval DOE-NE
• Pending receipt of adequate funding and timely DOE
approvals of Critical Decisions, MTS can start operating
in 2015
• Current cost range for MTS is $60M to $80M
• Project cost will be “baselined” during Conceptual Design
Slide 20
AHIPA Workshop, Fermilab, October 19, 2009
Summary
• MTS is not fully prototypic of a fast reactor and is
therefore not appropriate for providing final engineering
data needed to qualify fast reactor fuel
• Irradiation data obtained in MTS can advance our
understanding of fuels and materials performance in a
fast neutron spectrum
• MTS irradiation data, coupled with data obtained from
other irradiation facilities, can be used to validate
simulation models
• In addition to its primary mission of fission materials
testing, MTS is well suited for irradiating fusion materials
AHIPA Workshop, Fermilab, October 19, 2009