1. magnetic confinement - ENEA - Fusione

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3. FUSION TECHNOLOGY
3.7 Materials
(liquid metal velocity 0.5-1 m/s). The aim is to quantify
eventual degradation of the mechanical and elastic
properties of the composite because of corrosion, with the
use of nondestructive techniques including geometrical
dimensions, mass variation, longitudinal and torsional
dynamic moduli of elasticity (by the longitudinal and
torsional fundamental resonant frequency method).
The materials to be investigated include CERASEP N31, N41
and ENEA PIP composites.
The upgrading of the LIFUS2 facility at ENEA Brasimone to
increase the exposure temperature to 550°C was completed.
The exposure phase was completed for 100 and 1000 h. The
characterisation of the samples exposed for 100 h showed the
absence of erosion-corrosion phenomena but the presence of
consistent liquid infiltration (fig. 3.20). The characterisation of the samples exposed
for 1000 and 6000 h is ongoing.
3.7.2 Microstructural investigation of radiation effects in RAFM
steel by SANS
These activities are carried out in collaboration with FZK. Small-angle neutron
scattering (SANS) measurements were performed at the High Flux Reactor of ILL-
Grenoble. An automatic sample changer designed for handling highly activated
material (up to 1 Sv at 10 cm) was developed. OPTIFER (I and V) and F82H steels,
neutron irradiated at 250-450°C with 2.8 dpa, with and without post-irradiation
annealing at 525 and 700°C, were investigated. Non-irradiated oxide dispersion
strengthened (ODS) EUROFER97 samples (up to 0.5% Y 2 O 3 ) were also examined.
Under 2.8 dpa irradiation, the SANS cross section increases remarkably compared to
the non-irradiated samples, which reflects the presence of defects, such as He
bubbles. The ratio nuclear +
magnetic/nuclear scattering changes
significantly under irradiation, which
is a sign of changes in precipitate
composition. The difference between
the irradiated and reference
samples appears to be independent
of the orientation relative to
the applied magnetic field in the postirradiated
35.0
28.0
21.0
heat-treated specimens.
This can be attributed to the 14.0
growth of He bubbles. Figure 3.21
shows a comparison of oxide 7.0
particle distributions obtained by
transmission electron microscopy 0.0
(TEM) and SANS for the EUROFER97
0.0 7.0 14.0 21.0 28.0 35.0
ODS samples.
d (nm)
Rel. frequency
Fig. 3.20 - SEM
micrograph of sample
exposed for 100 h,
showing heavy Pb-17Li
infiltration.
Fig. 3.21 – Oxide particle
distributions in EURO-
FER97 ODS 0.3%.
Continuous line: data from
SANS measurements.
Dashed line: histogram
from TEM (Lindau et al.,
ICFRM 10 Proc.)
3.7.3 Mechanical properties of RAFM steel-base material and joints
The isothermal low cycle fatigue (LCF) programme without hold-time was
completed on both EUROFER97 and F82H mod. The final results confirmed the
behaviour found for the first set of tests. Both steels behaved like other hardened and
tempered martensitic alloys: no hardening was observed either for a strain-range of