1. magnetic confinement - ENEA - Fusione

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1. MAGNETIC CONFINEMENT
1.2 FTU Facilities
Table 1.II Machine efficiency in 2001
January February March April May June July September October November December
Total pulses 111 180 238 352 406 92 130 141 265 202
Successful pulses (sp) 103 159 214 312 375 80 116 138 239 173
I(sp) 0.93 0.88 0.90 0.89 0.92 0.87 0.89 0.98 0.90 0.86
Total
2117
1909
0.90
Potential experimental days 10 9.5 11 18 17 4 5 7 12.1 10
Real experimental days 5 8 10 14 17 4 5 7 12.1 9
I(ed) 0.50 0.84 0.91 0.78 1.00 1.00 1.00 1.00 1.00 0.90
104
91
0.88
Experimental minutes 1819 2879 3971 6023 7640 1803 2165 2561 4845 3867
Delay minutes 1323 1925 2402 2403 2801 621 640 1622 2672 1958
I(et) 0.58 0.60 0.62 0.71 0.73 0.74 0.77 0.61 0.64 0.66
A(sp/d) 20.60 19.88 21.40 22.29 22.06 20.00 23.20 19.71 19.75 19.22
A(p/d) 22.20 22.50 23.80 25.14 23.88 23.00 26.00 20.14 21.90 22.44
37573
18367
0.67
20.95
23.24
DELAY FOR SYSTEM (minutes)
January February March April May June July September October November December Total %
MACHINE 0 43 466 52 159 193 29 19 140 228 274 1603 8.7
POWER SUPPLIES 0 192 528 894 310 239 22 31 287 10 279 2792 15.2
RADIO FREQUENCY 0 81 59 280 697 738 188 112 247 221 53 2676 14.6
CONTROL SYSTEM (PROMETEO) 0 347 235 319 232 402 223 24 19 344 287 2432 13.2
DAS 0 0 0 172 44 92 7 4 52 63 54 488 2.7
FEEDBACK 0 20 0 0 22 0 0 17 27 24 10 120 0.7
NETWORK 0 143 208 92 0 0 0 0 0 461 84 988 5.4
DIAGNOSTIC SYSTEMS 0 213 219 85 179 276 17 166 89 133 150 1527 8.3
ANALYSIS 0 279 209 350 634 785 135 265 735 1009 734 5135 27.9
OTHERS 0 5 17 158 126 76 0 2 26 179 33 622 3.4
TOTALE 0 1323 1941 2402 2403 2801 621 640 1622 2672 1958 18383 100
Summary of machine maintenance
Maintenance of the FTU system was carried out according to schedule. Visual
inspection of the vacuum vessel revealed ten displaced tiles, most of which in the
upper and bottom rows. The rupture was investigated through specific laboratory
tests and it was found that the fragility of tungsten-zirconium-molybdenum (TZM)
can damage the supporting-screw thread. A new design tile-support structure was
developed and will be tested in 2002.
The new data storage system based on SAN architecture was released, and the whole
FTU experimental data archive is on line. A preliminary test of Opto22 technology in
slow acquisition, i.e., replacing the traditional PLC, was carried out.
Future activities
In 2002 the machine will operate up to July and then from mid-September to mid-
October if the injector for launching pellets from the high-field side is ready. New
diagnostics and the new passive-active multijunction (PAM) lower hybrid launcher
will be installed during the second shutdown in 2002. All four ECRH gyrotrons will
be in operation, so a total power of 1.6 MW should be available. A new density
feedback system based on VME architecture will be implemented.
Boronisation system
Direct current glow discharge deposition is used to coat the vacuum vessel walls
with a boron film. The deposition system is the same as that used for the vacuum
chamber conditioning, but the vessel is fuelled with a mixture of helium and
diborane (90% He and 10% B 2 H 6 ). The aim of boronisation is to reduce the effective
charge Z eff and the plasma radiation losses by introducing a low-Z element as firstwall
material.