Prime pagine RA2010FUS:Copia di Layout 1 - ENEA - Fusione

technology programme (cont’d.)
progress report
2010
065
low (some gauss) stray field produced by the magnetization induced in the ferromagnetic materials on the
plasma region required a careful analysis due to the presence of the high poloidal field produced by the plasma
itself and by the PF coils that could not be excluded from the analysis itself.
The stray field inside the whole main ITER building was also evaluated for several plasma scenario times
(fig. 3.16) and the maximum magnetization of all the main ferromagnetic components was calculated (1.6 T
for the NBI shielding boxes, 0.55 T for the iron doors, 0.5 T/m 3 for the homogenised material including the
rebars and the concrete of the building).
Pre–compression rings final design qualification
The ITER pre–compression rings activities continued in ENEA Frascati with the fifth ultimate tensile strength
(UTS) test performed on a ring scaled mock–up with a diameter of 1 meter (fig. 3.17) (ITER Contract
09–4300000015) [3.8,3.9]. This was the latter of six UTS tests on six different mock–ups. Four rings were
manufactured with the vacuum pressure impregnation (VPI) technique developed and optimized in ENEA
while the other two were produced by the filament wet winding
(WW) industrial conventional process.
The mock–ups were dimensionally checked and x–rays surveyed
before tests. Then UTS tests were carried out by loading the rings
with radial displacement increments of 0.1 mm by means of the
ring hydraulic testing facility in ENEA Frascati and following as
close as possible the standard test method ASTM D3039 for
tensile properties of polymer matrix composite materials.
UTS tests showed an average strength of 1550 MPa (mean hoop
stress in the cross section) and constant tensile modulus of
elasticity up to failure. UTS obtained on the VPI rings was
1584 MPa, higher than UTS on the WW rings, 1485 MPa.
Figure 3.17 – Pre–compression ring
dismantling after test
The volumetric glass content of the rings was measured on some of the rings after test, resulting in an average
of 70% both for VPI and WW rings.
The testing activity continued with a stress relaxation test performed on a VPI ring mock–up for 210 days at
a stress level of 950 MPa. The mock–up showed a stress relaxation of less than 0.5% and a residual strain of
0.02% after test. No defects were detected by x–rays after test.
Another WW ring was then manufactured and will be stress relaxation tested during 2011. Characterization
of the ring composite material has been completed with creep, shear and compression tests.
On the basis of the ENEA R&D activity, at the end of 2010 F4E launched a call for tender for the
procurement of the ITER full scale pre-compression rings where ENEA will be involved to qualify preliminary
scaled rings.
3.4 Remote Handling and Metrology
ITER in vessel viewing system
ENEA developed and tested a prototype of a laser in vessel viewing and ranging system (IVVS), that uses the
amplitude modulated laser radar concept and is based on an intrinsically radiation resistant concept and
architecture to withstand the severe ITER conditions. It already approaches the target specification requested
for ITER, although its present layout is not capable to withstand all the ITER environmental conditions.
In late 2008, ENEA won a grant launched by F4E for the conceptual design of the final ITER in–vessel
inspection prototype and the assessment of the present IVVS prototype. The activity started in April 2009 and
continued in 2010 to evaluate the potential application of the ENEA IVVS prototype for ITER in–vessel
inspection and then produce the conceptual design of an IVVS system compliant with all the ITER
requirements and the related test bed. The work has been divided into three main tasks.