Materials for Advanced Fission and Fusion Reactors · 1 Managed by UT-Battelle for the U.S....

1 Managed by UT-Battelle for the U.S. Department of Energy

Materials for Advanced Fission and Fusion Reactors

Steve Zinkle Nuclear Science & Engineering Directorate

Oak Ridge National Laboratory

NE50: Symposium on the Future of Nuclear Energy

School of Nuclear & Radiological Engineering & Medical Physics

Georgia Tech, Atlanta, GA

November 1, 2012


Timeline of some key events for nuclear energy and materials and computational science

1940 1950 1960 1970 1980 1990 2000 2010

CP-1 Graphite

Shippingport

Development of Mat. Sci.

as an academic discipline

reactor JET: Q=0.65, 0.5s

1 Gflops achieved;

high performance

computing centers

established

1 Tflops 1 Pflops

Nuclear >10%

US electricity

ENIAC

Tokamak era begins

ITER

NIF

1st stellarator

& Tokamak

1st MD simulation of radiation damage

(500 atoms, 1 min. time step)

multimillion atom MD simulations

(~1 fs time step)

TFTR: Q=0.27 JT-60:

Qeq=1.25


US Reactor Fuel Performance: Higher burnup with fewer failures

Zinkle & Was, Acta Mater., in press


Materials performance is key for economic and safe fission reactor operation in current LWRs

• Heat generation in UO2-based fuel pellets to high burnup

• Heat transfer across Zr alloy cladding; fission product containment under normal and design-basis transient conditions

• Numerous core internal structures to securely position core

• Reactor pressure vessel for containment of fission products

• Piping and steam generator equipment for heat conversion to electricity


ARIES-AT Magnetic Fusion Energy concept

F. Najmabadi et al. Fus. Eng. Des. 80 (2006) 3


New technology, New requirements

Gen-III

Pressurized

Water Reactor

Gen-IV

Fast Reactor

Very High

Temperature

Reactor

Coolant Water Sodium Helium

Power Density (MW/m3) 100 350 5

Coolant Temp. (C) 330 550 1000

Net Plant Efficiency (%) 34 40 50


Comparison of Gen IV and Fusion Structural Materials Environments

fusion SiC

V alloy, ODS steel

F/M steel

All Gen IV and Fusion concepts pose

severe materials challenges

S.J. Zinkle & J.T. Busby, Mater. Today 12 (2009) 12

S.J. Zinkle ,OECD NEA Workshop on Structural

Materials for Innovative Nuclear Energy Systems,

Karlsruhe, Germany, June 2007


Radiation Damage can Produce Large Changes in Structural Materials

• Radiation hardening and embrittlement (<0.4 TM, >0.1 dpa)

• Phase instabilities from radiation-induced precipitation (0.3-0.6 TM, >10 dpa)

• Irradiation creep (<0.45 TM, >10 dpa)

• Volumetric swelling from void formation (0.3-0.6 TM, >10 dpa)

• High temperature He embrittlement (>0.5 TM, >10 dpa)

100 nm

50 nm

100 nm S.J. Zinkle, Phys. Plasmas 12 (2005) 058101; Zinkle & Busby, Mater. Today 12 (2009) 12


Examples of radiation damage degradation

Zinkle & Was, Acta Mater., in press

Contributor to SCC in LWR internals Stainless steels are not attractive options

for high dose Gen IV reactor applications

Tirr=420-580oC


There are many approaches for radiation resistance

high density of nanoscale precipitates or particles (e.g., ODS steel or Ti-modified austenitic stainless steel)

L.K. Mansur & E.H. Lee, J. Nucl. Mater. 179-181 (1991) 105

Fe-13Cr-15Ni CW (P,Si,Ti,C)-modified High mag of “b”

Operation at temperatures where vacancies are immobile (e.g., SiC composites)

Current LWR core internals

Gen IV SFR core internal structures

after S.J. Zinkle, Chpt. 3 in Comprehensive Nuclear Materials (Elsevier, 2012)


Heat to Heat Variability has been a Common Feature of Structural Alloys

Heat 1

Heat 2

Heat 3

13.5 N-mm-2

helium

Time (hrs)

Heat 1

Heat 2

Heat 3

5000 10000 15000 20000

Cre

ep s

train

(%

)

13.5 N-mm-2

helium

P.J. Ennis et al. 1984

Alloy 617 Thermal Creep


New steels designed with computational

thermodynamics exhibit superior mechanical

properties compared to conventional steel

• Three experimental RAFM heats (1537, 1538, and 1539), together with an optimized-Gr.92 heat (C3=mod-NF616), were investigated

• Tensile strength of new TMT steels were much higher than conventional steels

• Dramatic improvement in thermal creep strength also observed

0 100 200 300 400 500 600 700 800

200

400

600

800

NF616

1537

1538

1539

Mod-NF616

Yie

ld S

trength

(M

Pa)

Temperature (oC)

PM2000

F82H

0 100 200 300 400 500 600 700 8000

5

10

15

20

25

30

35

40

1537

1538

1539

Mod-NF616

Tota

l E

long

atio

n (

%)

Temperature (oC)

PM2000

NF616

L. Tan et al. (2012)

1.6X


Modern steels exhibit reduced hardening and less

embrittlement compared to 1960s-era RPV steel

To = 0.3

y RAFM

To = 0.7

y RPV

YIELD STRENGTH INCREASE, MPa

0 100 200 300 400 500 600T

o SHIFT, oC

0

50

100

150

200

250

F82H-IEA

F82H-HT2

9Cr-2WVTa

Eurofer97(Lucon, SCK-CEN)

Eurofer97(Rensman, NRG)

RPV Steels

(Sokolov, ASTM STP 1325)

T0 s

hif

t, o

C

Embrittlement rate of modern steels

is about 40% that of RPV steels

(normalized to same amount of

radiation hardening)

M.A. Sokolov et al., J. Nucl. Mater. 367-370 (2007) 68 J. Rensman, NRG report 20023/05.68497/P (2005);

M. Lambrecht et al., J. Nucl. Mater. 406 (2010) 84

Hardening rate of modern steels is

about 50% that of RPV steels

RPV steel

Plotted data are 8-9%Cr steels; similar results obtained for

pressure vessel-relevant steels such as modern 2-3%Cr steels


Advanced Manufacturing Techniques offer the potential to enable rapid fabrication of complex geometries

Examples of additive manufacturing technologies


High

temperature

during loss of

active cooling

Improved Cladding Properties to

maintain core coolability and retain

fission products

-High temperature clad strength and

fracture

-Thermal shock resistance

-Resistance to melting

-Resistance to hydrogen embrittlement

Improved Fuel Properties

-Lower operating temperatures

-Clad internal oxidation

-Fuel relocation / dispersion

-Enhanced retention of fission

products

-Fuel melting safety margin

Suppressed Reaction Kinetics with Steam

to minimize enthalpy input and hydrogen

generation

-Oxidation rate

-Heat of oxidation

There are three major potential strategies for

accident tolerance

• potential options for fuel cladding include:

– Oxidation-resistant austenitic steels

– Oxidation-resistant coatings on Zr alloy cladding

– Ceramic matrix composite cladding


Thermal creep strength of some candidate cladding materials

• Mo alloys and steels (and SiC/SiC, not plotted) offer improved high temperature strength


High-Pressure Steam Oxidation Tests: Comparison of the Extent of Steam Reaction Various materials exposed to pure steam for 8 hours (various flow rates and pressures):

• Zircaloy: Pawel-Cathcart and Moalem-Olander data

• 317 Stainless Steel: ORNL high-pressure tests; thickness loss data

• NITE and CVD SiC: ORNL high-pressure tests; thickness loss data

• 310 Stainless Steel: ORNL high-pressure tests; mass gain data converted to

thickness loss

• FeCrAl Ferritic Steel: ORNL high-pressure tests; mass gain data converted to

thickness loss

0.1

1

10

100

1000

750 800 850 900 950 1000 1050 1100 1150 1200 1250 1300 1350

Mate

rial

Recessio

n [

µm

]

Temperature [ C]


Several Accident Tolerant Fuel Concepts

are Under Consideration, including:

• UO2 – Zircaloy (Base Case)

• UO2 – FeCrAl (oxidation resistant Steel)

• FCM – FeCrAl Fully Ceramic

Microencapsulated Fuel

UO2

Pellet

Zircaloy

Cladding

Conventional LWR UO2 Rod

Coated

Fuel

Particle

Cladding

(Zircaloy,

Steel, SiC)

LWR FCM Rod

FCM

Pellet

TRISO

Fuel

Particle


There are numerous proposed fusion blanket technology options, all of which are at a relatively immature TRL

• Key issues include tritium recovery/transport, coolant compatibility, safety, waste disposal/recycling, radiation damage effects, and lifetime limits

• The 3 leading structural materials candidate systems are ferritic/ martensitic steel, V alloys, and SiC/SiC (based on safety, waste disposal, and performance considerations)

• These blanket concepts would utilize a variety of conceptually interesting (but unproven on engineering scale) tritium recovery processes

Structural

Material

Coolant/Tritium Breeding Material

Li/Li He/PbLi H2O/PbLi He/Li ceramic H2O/Li ceramic FLiBe/FLiBe

Ferritic s teel

V alloy

SiC/SiC


Fusion energy research is approaching a transition from plasma science to fusion engineering science

Option A: IFMIF + fission reactors +ion beams + modeling

Option B: robust spallation (e.g., MTS) + fission reactors + ion beams + modeling

Option C: modest spallation (e.g.,SNS/SINQ) + fission reactors + ion beams + modeling

• An intense neutron source (in concert with enhanced theory and modeling) is proposed to improve understanding of basic fusion neutron effects and to develop & qualify fusion structural materials

New facilities would expand current

knowledge base on ferritic steels


Detailed timeline of some key facilities for nuclear energy and materials

1942 1944 1946 1948 1950 1952 1956 1958

CP-1

Shippingport

ORR

Obninsk

AM-1

1st radiation damage paper

E.P. Wigner

J. Appl. Phys. 17 (1946) 857

1954

MTR

BSR Graphite

reactor

ETR

Calder

Hill

CP-5

BGRR


Conclusions

• The impact of materials on the future of fission and fusion energy is pronounced

– New materials for improved accident tolerance and core structures of light water fission reactors; Several potential candidates for improved accident tolerance exist, but further R&D is needed to examine behavior under normal and potential accident scenarios

– Existing structural materials face Gen IV fission and fusion reactor design challenges due to limited operating temperature windows

– May produce technically viable design, but not with desired optimal economic attractiveness

• Substantial improvement in the performance of structural materials can be achieved in a timely manner with a science-based approach

– e.g., Design of nanoscale features in structural materials confers improved mechanical strength and radiation resistance

– Selection of accident-tolerant fuel options for light water fission reactors

Materials for Advanced Fission and Fusion Reactors · 1 Managed by UT-Battelle for the U.S....

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Transcript of Materials for Advanced Fission and Fusion Reactors · 1 Managed by UT-Battelle for the U.S....