Analysis of quench-vent pressures for present design of ITER TF coils

The effects of a quench within the toroidal-field coil (TF) based on current International Thermonuclear Experimental Reactor (ITER) design are examined in a preliminary analysis. The intent is to assist ITER designers while more accurate computer codes are being developed, and to provide a check against these more rigorous solutions. Rigorous solutions to the quench problem are very complex, involving three-dimensional heat transfer, extreme changes in heat capacities and copper resistivity, and varying flow dynamics within the conductors. This analysis addresses all these factors in an approximate way. The result is much less accurate than a rigorous analysis; in fact, an error margin of as much as 30 to 40% is possible. However, it is believed that this analysis can still be very useful to the coil designer. Coil pressures and temperatures vs. time into a quench are presented. Rate of helium vent, energy deposition in the coil, and depletion of magnetic stored energy are also presented. Peak pressures are high (about 43 MPa). This is due to the very long vent path length (446 m), small hydraulic diameters, and high current densities associated with ITER's cable-in-conduit design.<
>