Moving a 400-ton magnet

Over a busy weekend in early May 1981, a method used by the ancient Egyptians to build the pyramids was used to move a massive piece of 20th century technology across the Lab grounds. On the move was the first of two immense superconducting yin-yang magnets, weighing 400 tons each, from its fabrication yard off First Street to its permanent home in the Mirror Fusion Test Facility (MFTF), Bldg. 431.

The MFTF, an advanced experimental fusion device, was designed to be an intermediate step between the existing mirror machines and an experimental fusion reactor. By 1981, construction on the original MFTF design, which had begun in 1977, had been substantially modified into a large tandem mirror configuration called MFTF-B. The scope of the project was immense, with a 58-meter-long vacuum vessel and the largest set of superconducting magnets in the world. 

The move of the first yin-yang magnet in May 1981 started earlier in the week with the lowering of the massive magnet from its support frame into a sand pile on the ground. That Friday, the 400-ton magnet was moved from the fabrication yard onto First Street. The following morning, workers from Riggers International of Oakland rigged the massive magnet to a sled-like frame, positioned on top of specially hardened eight-inch oak log rollers. The sled had been placed in front of a pathway lined with plywood, from First Street down South Entrance Drive (South Gate Drive), that would serve as a smooth roadway for the magnet's journey to it's new home in Bldg. 431.

Using the ancient Egyptian transport method, the work crew began to pull the sled, via a cable attached to a huge crane, moving the transport slowly across the roller logs. As the sled progressed, logs behind the transporter were hand-carried to the front of the craft, so that a constant supply of logs allowed the transport to continuously lumber forward. While the ancient method appeared to be a slow process, it required only one weekend, which included several turns and changes in elevation.

Later that year, the second of the two yin-yang magnets was transported using a then newly-developed transfer technology. Instead of using a rigged sled, atop rolling logs, the 400-ton magnet was placed on a trailer bed, with 156 self-leveling independently controlled wheels. This automatic transport was able to move the second magnet in less than one day, in contrast to the long weekend required using roller logs.

Unfortunately, a few years later and shortly after the construction on the MFTF-B was completed in 1986, magnetic fusion research suffered a setback at LLNL, and the MFTF-B was shuttered before it was ever turned on.