Inspection software is playing a vital role in the construction of a nuclear-fusion machine that could produce inexhaustible, safe and environmentally attractive energy.
Delcam's PowerInspect inspection software is playing a vital role in the construction of a nuclear-fusion machine that could produce inexhaustible, safe and environmentally attractive energy. The software is being used on two Romer/Cimcore inspection arms to perform the measurements required to place several tonnes of stranded copper wire that make up the machine's magnetic conductors. The machine, known as the National Compact Stellarator Experiment (NCSX), is being built by the Princeton Plasma Physics Laboratory in New Jersey, with support from the Oak Ridge National Laboratory in Tennessee.

The unit will be more than 9.5m in diameter and almost as high.

It is planned to have the device ready for testing in 2009.

Nuclear fusion joins atomic nuclei to release huge amounts of energy.

The reaction occurs in a hot, ionised gas or plasma.

Most fusion devices to date have used toroidal vacuum vessels and flat magnetic coils.

However, these simple geometries yield plasmas that are stable for only fractions of a second.

In contrast, plasma in the NCSX will be controlled in a helically-twisted toroidal vessel, with complex-shaped magnets to generate and maintain more stable plasma.

The 18 individual mandrels on which the copper conductor is wound are frequently characterised as twisted and distorted raceways.

Conductors are placed in side-by-side raceways around the inside of each mandrel.

With all the mandrel's twists and turns, each raceway is nearly 10m long.

When energised, the magnet system will generate enough force to lift a railway locomotive.

'PowerInspect is used to make thousands of dimensional measurements of the flexible copper conductor, while ten or eleven layers are being wound on, perhaps, the most strangely-shaped mandrel ever made', said Steve Raftopoulos, project engineer in charge of metrology.

'The portable CMM can reach into the mandrel's severely-restricted spaces, while the software gives team members continual feedback for positioning and adjusting the conductor'.

After the coils are wound, PPPL uses the CMMs and PowerInspect software for feedback in final positioning and adjustment of the conductor.

'The software report is dumped to a spreadsheet', said Raftopoulos.

'This data guides the coil-winding team in loosening the clamps and tweaking the alignment of the conductor layers, helping us get the coil in the right place with minimal manipulation'.

'Because much of this project is still experimental, it calls for a lot of dimensional measurements', explained Raftopoulos.

'Measurement and verification is both crucial and almost endless in building components so sensitive to any deviations from the ideal'.