INDUSTRIAL RESEARCH AT E.N.E.A. R. Coppola ENEA-Casaccia, Via - - PowerPoint PPT Presentation

CRISP Wokshop on Imaging with Neutrons, ILL 17 March 2014

INDUSTRIAL RESEARCH AT E.N.E.A.

• R. Coppola

ENEA-Casaccia, Via Anguillarese 301, 00123 Roma, Italy

CURRENT ACTIVITIES SANS studies of high-dose irradiated steels, neutron diffraction characterization of plasma-facing components (EFDA, ITER) SANS studies of low-dose irradiated nuclear steels, textures in ODS materials (EERA JPNM) Neutron diffraction studies of fuel cell electrodes (Italian Ministry for Economic Dev., Ansaldo FC, SOFCPower) Participation in IAEA CRP’s for development of neutron techniques applied to energy research materials and in NeT – JRC Petten

TRIGA RC-1 – 1 MW at ENEA-Casaccia

Specific applications

• Radiography and Neutron Tomography
• Material activation
• Thermal cavity availability
• Neutron Diffraction
• Epithermal flow generation
• Training for students and safety authority staff

• Dr. M. Klimenkov KIT

Irradiated Structural Material

Chemical compositions of the test alloys in

wt.%

Heat C Si Mn Cr Mo Ni B V W N Ta Fe

EUROFER97 0.12 0.04 0.48 8.91 <0.001 0.02 < 0.001 natB 0.2 1.08 0.02 0.14 Rest 806 ADS2 0.109 0.020 0.602 9.31 0.002 0.005 0.0082 natB 0.190 1.27 0.021 0.055 Rest 826 ADS3 0.095 0.031 0.395 8.80 0.046 0.008 0.0083 10B 0.193 1.125 0.028 0.088 Rest 825 ADS4 0.10 0.03 0.38 9.00 0.028 0.006 0.1160 10B 0.197 1.06 0.025 0.08 Rest

Heat Treatment: 1040 °C 30 min + 760 °C 90 min

< 10 ppm natB

82 ppm natB 83 ppm 10B 1160 ppm 10B

<10 appm He

~80 appm He ~415 appm He ~5800 appm He

He Concentration Neutron fluence rate: 1.42x1018 m-2s-1 (thermal); 3.99 x1018 m-2s-1 (fast, >0.1 MeV) Irradiation HFR-Petten up to 16.3 dpa at T = 250°C, 350°C, 450°C

• Dr. M. Klimenkov KIT

Investigation of B doped alloys

He bubbles in ADS3 (450°C), 415 appm He, 16 dpa Cuboidal helium bubbles decoration of grains boundaries and dislocations lines

D22 measurements (in coll. Dr. L. Porcar)

Number (left) and volume (right) distribution functions obtained from SANS nuclear cross-sections of samples ADS4 B-alloyed Eurofer97 5600 appm helium neutron irradiated at 400°C to 16 dpa (red, volume fraction 0.038) and ADS3 B-alloyed Eurofer97 400 appm He neutron irradiated at 450°C to 16 dpa (blue, volume fraction 0.007).

Best-fit distributions 400 and 5600 appm He

SANS-TEM comparison ADS4 16 dpa 400°C 5600 appm He Black squares: SANS best-fit volume distribution (A. U.) R > 15 Å Blue rectangles: TEM histogram (Dr. M. Klimenkov)

H-loaded Zr-Nb 2.5 wt% tubes

Axial Radial

H-free reference material H-loaded by cathodic charge + 24 h 400°C in N2 (Nb hydrides) provided by Dr. J. Santisteban - CNEA, in the frame of IAEA CRP

radially averaged SANS cross sections (cm-1 vs nm-1) of CNEA H-loaded and H-free Zr-Nb 2.5 wt % samples (unpublished, coll. Dr. A. Heinemann, TUM)

H-free H-loaded (unpublished coll. Dr. A. Heinemann, TUM)

2D SANS intensities at 20 m 12 Å (A.U.) of CNEA Zr-Nb tubes

Best-fit and size distributions for the difference between CNEA H-loaded and H- free samples obtained by the B-spline method

Scheme of a molten carbonate fuel cell, where the electrolyte is a combination of alkali carbonates, water is produced at the anode site and CO2 is needed at the cathode site.

Neutron diffraction studies of FC electrodes

• All components of the

HTFC can be studied, both separately and as a whole

• Observation of

crystallographic (lattice) structure changes (not too localized – only for homogeneous effects)

• Diagnostics under

controlled environment (T & atmosphere not restrictive)

• Penetration possible

through several mm of shielding and containing material

The potential of Neutron Diffraction

Porous Ni-Cr (5 wt%) anodes (1 mm thick) were coated with CeO2 protective layer obtained by sol-gel technique followed by heat treatment at 650°C under N2–H2 5%

NiCr/CeO2 anodes

The following samples were investigated by neutron diffraction (no chance with grazing X-Rays!):

• N. 1: Uncoated NiCr substrate as a reference
• N. 3: as N. 1 with standard CeO2 deposition parameters
• N. 3bis as N. 1 with optimised CeO2 deposition parameters

Ni-Cr Ni-Cr-Ce

NiCr CeO2 NiO NiO mag.

D20, in coll. J. Rodriguez-Carvajal, V. Nassif, L. Laversenne

NiCr/CeO2 anodes: results

Optimizing the CeO2 deposition parameters the electrode as a whole can be accurately characterized at D20: The following crystallographic phases were identified: NiCr 68.4%, CeO2 6.3%, NiO (n.+m.) 25.3%

NiCr/CeO2 anodes: results

Pathway towards in-situ measurements 1. Characterize as-received materials and define optimum measurement conditions 2. Analyze each treated (operated) material/component by ND analysis and compare whether the differences in crystallographic structure with the as-received sample (e.g. CeO2 vs Ce2O3, hexagonal vs cubic lattice or different lattice spacing) can be understood 3. Prepare complete fuel cell for ND analysis (carry out poisoning, long term

• peration, accelerated testing protocol, etc.)

4. Carry out ND measurement (short spells only)



OK

Too many to mention!  But which should be monitored in situ?

Degradation effects in HTFC

Scheme of the investigated Eurofer welded plate and a cross-sectional picture of the weld. The principal stress axes are the longitudinal direction (along the weld, in the plane of the plate), the transverse direction (the direction across the weld line, in the plane of the plate) and the normal direction (normal to the surface of the plate). The neutron diffraction measurements were carried out at mid-length of the plate, at different distances from the weld centre.

Residual stresses in Eurofer97 TBM welded mock-up’s (in collaboration with CEA)

Longitudinal stresses in MPa (dots) determined by neutron diffraction as a function of the distance, in mm, from the weld centre (“0”). For comparison, the longitudinal calculated stresses are shown, indicated by squares.

Ref.: R. Coppola, O. Asserin, P. Aubert, C. Braham, A. Monnier, M. Valli, E. Diegele, JNM 417 (2011) 51

STRESSES IN WELDED EUROFER97 STEEL

IM + IN IN

H = 1.4 T

n m N M

A A       

NUCLEAR AND MAGNETIC SANS

a) reference sample, b) irradiated sample

Nuclear and magnetic SANS cross-section

2 2

) ( / ) ( 1 ) ( ) ( ) ( ) (

nucl mag nucl mag nucl

dQ ddQ d dQ d Q R             

Polarised SANS





   

2 2 2

) , ( ) ( ) ( ) ( ) ( R Q F R V R N dR d Q d 