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| Hauptseite > Publikationsdatenbank > Problems of heat removal at first wall components of intor |
| Book/Report | FZJ-2018-01542 |
1980
Kernforschungsanlage Jülich, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/17523
Report No.: Juel-1691
Abstract: The heat loads at the first wall components of future large tokamaks will be greatly different from those of existing devices. The following major differences between the heat loads in present day machines and future tokamaks of INTOR-size /1/ must be taken into consideration : While the average heat load in present tokamaks is between 0.01 and 0.1 MW/m$^{2}$ it will be in the range of 0.4 MW/m$^{2}$in the future generation. The pulse duration is at present in the order of 1 s and corresponds to the thermal penetration time in the applied wall materials, thus the total energy can be taken by the thermal inertia of the wall and be removed between discharges. For INTOR, however, the pulse duration is assumed to be 100 s requiring steady staue cooling. Finally, the high neutron fluxes in reactor-like devices represent an additional heat source by which the bulk of the first wall is heated. This nuclear heating amounts to about 10 MW/m$^{3}$ per 1 MW/m$^{2}$ of incident neutron flux in stainless steel. Except of the normal operating conditions there are fault conditions which cause extreme heat loads an the first wall components like runaway electron dicharges or major plasma disruptions. The latter will be discussed here, because they are assumed to represent another problem to the first wall components different from that of present day machines. In these considerations the total thermal energy content of the plasma, related tothe plasma surface, is the relevant parameter. In present day tokamaks the energy content is between 20 and 100 kJ whereas the thermal plasma energy of INTOR is assumed to be 200 MJ. Related to the corresponding plasma surface, PLT-like devices yield about 5 $\cdot$10$^{-3}$ MJ/m$^{2}$ whereas INTOR yields about 0.7 MJ/m$^{2}$. Although the disruption time will probably increase with larger plasma size, the resulting heat loads still are likely to exceed the ones experienced in present experiments by an order of magnitude.
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