Page 381 - Fundamentals of Magnetic Thermonuclear Reactor Design

Mechanics of Magnetic Fusion Reactors Chapter | 12 359

FIGURE 12.7 Toroidal stress in the PF1 coil conductor jacket (MPa). (Copyright ITER Organiza-
tion, 2017).

FIGURE 12.8 Maximum allowable jacket stress as function of the loading cycle asymmetry ratio.
(Copyright ITER Organization, 2017).

Actual stresses in the insulating layer and the insulation strength are de-
termined in a similar manner. A replacement of a composite winding with a
homogeneous anisotropic object is an efficient method for analysing an MS me-
chanical behaviour. It enables a prompt assessment of operating stresses, which
is particularly important at the early stages of the design process. One should
proceed from the cyclic symmetry condition when doing the average-to-actual
strain conversion. This may introduce some error into the calculation, if the
area under review is close to the winding surface layers. For instance, in PF1,
such areas are most loaded (Fig. 12.6). Still, when applied to PF1, this approach
demonstrates the winding’s adequate safety factor and validates its resistivity
to cyclic stresses. When in operation, the PF1 conductor is close to the uniaxial