Table 1.1:
Operating conditions for the first-wall components
of ITER and a DEMO-like reactor. As ITER will be an experimental reactor,
the projected number of cycles will be very much higher than any commercial
power plant reactor (Bolt et al., 2002). PFM = Plasma facing material,
SS = stainless steel, RAFM = reduced activation ferritic/martensitic steel, dpa = displacements per atom, appm = atomic parts per million. MW yr = megawatt years - 1 MW yr ≈31.5 TJ.
|
ITER |
DEMO-like reactor |
Component replacements |
None |
5 year cycle |
|
|
|
Average neutron fluence (MW yr m-2) |
0.3 |
10 |
Displacement damage (dpa) |
3 (SS) |
120 (RAFM) |
Helium production (appm) |
30 |
1200 |
|
|
|
Normal operation |
|
|
Number of cycles |
30000 |
<1000 |
Peak particle flux (1023 m-2 s-1) |
0.01 |
0.02 |
Surface heat flux (MW m-2) |
<0.5 |
<1 |
PFM operating temperature (°C) |
Be: 200 - 300 |
W: 550 - 700 |
|
|
Table 1.2:
Functions and requirements of a fusion
power-plant blanket structure. Tritium breeding occurs through the use of coatings such as lithium, which produce tritium under neutron bombardment (Smith et al., 1994).
Primary functions of the blanket |
- Convert energy into sensible heat |
- Breed tritium for the fuel cycle |
|
Primary requirements of the blanket |
- Adequate tritium production |
- Acceptable tritium recovery |
- Efficient heat recovery |
- Acceptable reliability and operating lifetime |
- Ease of assembly, maintenance, and repair |
- Acceptable post-irradiation environmental impact |
- Acceptable economics |
|
|