Test program to determine the mechanical properties of the NCSX modular coils

The National Compact Stellarator Experiment (NCSX) is the first of a new class of stellarators known as "compact stellarators". The differentiating feature of a compact stellarator is the use of plasma current in combination with external fields to accomplish shaping and confinement. The modular coil set for NCSX is comprised of 18 complex shaped windings contained in an integral shell. There are three distinct modular coil shapes; six of each embody the complete set. To fabricate these windings to the precise shapes required, stranded copper cable conductor is wound on stainless steel winding forms. A single modular coil conductor turn is comprised of four rectangular compacted copper ropes in a two-by-two configuration which are vacuum impregnated. Groups of conductors are placed in a mold where they are bonded into bundles forming the modular coils. An in-depth mechanical test program is required to verify the integrity of the modular coil manufacturing process. This would be followed by an extensive test program, which would evaluate the vacuum impregnation of the coil and determine the thermally dependent mechanical properties of the coils. Properties to be evaluated include tension, compression, shear and flexural moduli and strengths. Thermal coefficients of expansion for various coil components are to be determined over the entire range of NCSX operating temperatures. Other specific tests, including an evaluation of resin cure shrinkage, are also planned. This paper will report the findings and results of this test program to date.