1. magnetic confinement - ENEA - Fusione

3. FUSION TECHNOLOGY 89
3.7.8 Mechanical characterisation of materials with miniaturised
specimens
Development of the portable flat-top indenter for mechanical characterisation
(FIMEC) continued in 2001. Following the achievement of the demonstrative
apparatus for in situ testing, which is based on the use of a 0.7-mm-diam flat
indenter, a portable prototype was designed. Work was also started on developing a
numerical methodology as a comprehensive tool for interpreting the load
penetration curves of different materials.
Two options of the portable FIMEC apparatus were analysed: The first is based
on the same stepping motor and load displacement detection features as used in
the fixed apparatus; the second is more compact and has a different layout, with
an encoder, a small motor and a kinematic chain which drives the indenter tip.
Both solutions are provided with a fixing tool suitable for cylindrical and flat
geometry.
3.8.1 Interaction between lead-lithium alloy and water in DEMOrelevant
conditions (EU Task TTBA-5)
Large water leaks
3.7 Materials
3.8 Liquid Metal Technology and
Hydrogen Effects on Materials
The interaction between molten lead-lithium alloy (in a eutectic composition) and
pressurised water is studied to predict the behaviour of a water-cooled lithium-lead
(WCLL) blanket module in the case of a cooling-tube rupture.
In 2001, three tests (#3,4,5) were conducted at the LIFUS 5 apparatus at ENEA
Brasimone in thermal-hydraulic conditions similar to those foreseen for the WCLL
DEMO blanket.
In test #3, water was injected into the reaction tank at a pressure of 155 bar with
different values of sub-cooling and different free volumes in the expansion vessel.
The initial liquid metal temperature was fixed at 330°C.
In test #4, the water temperature was fixed at 325°C (corresponding to a water subcooling
of about 20°C), the free volume of the expansion vessel was 5 l and the
duration of water injection was 6 s. After about 2 s from the beginning of the test, the
rupture disk D1 (on the line connecting the expansion vessel to the dump tank)
failed, with subsequent depressurisation of the system. Because of the large amount
of injected water, a significant heat effect was also found; a maximum temperature of
683°C was detected in the upper part of the reaction vessel, with an increase of 353°C
over the initial value.
In test #5, water was injected at 265°C, the compressibility of the system was reduced
by decreasing the free volume in the expansion vessel from 5.0 to 4.0 l and the time
of water injection was increased to 12 s. During the experiment, 3.28 kg of water were
injected into the reaction vessel. A maximum temperature of 525°C was detected in
the upper part of the reaction vessel, about 10 s from the beginning of the test, with
an increase of 195°C over the initial value.
Comparing tests #3 and 5, it appears that the free volume in the expansion vessel is
much more significant than the water enthalpy in determining the pressurisation
evolution of the blanket module. This consideration is confirmed by comparing tests
#4 and 5.