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Nov 06, 2024

US completes first key magnet for apple-shaped nuclear fusion reactor

PPPL states that the quadrants are going through a process called vacuum pressure impregnation (VPI). Abhishek Bhardwaj An overhead photo of the National Spherical Torus Experiment-Upgrade (NSTX-U).

PPPL states that the quadrants are going through a process called vacuum pressure impregnation (VPI).

Abhishek Bhardwaj

An overhead photo of the National Spherical Torus Experiment-Upgrade (NSTX-U).

Michael Livingston/PPPL Communications Department

The Princeton Plasma Physics Laboratory (PPPL) has announced the completion of the intricate process of building the first quadrant of the magnet at the heart of the National Spherical Torus Experiment-Upgrade (NSTX-U) nuclear fusion reactor.

This is a major milestone for the PPPL’s nuclear fusion experiment, which comes under the United States Department of Energy (DOE).

PPPL stated that “it assembling two high-current magnets to create the toroidal field-ohmic heating coil (TF-OH) bundle. The magnets make up the core of the NSTX-U, similar to the core of an apple. They are designed to produce the highest magnetic field strength of any large spherical torus.”

The toroidal field (TF) coil is a 19-foot tall inner magnet which resembles a telephone pole. It carries up to four megaamps of electric current or 4 million amps to stabilize and confine the hot plasma in fusion experiments, according to a press release by PPPL.

There will also be an outer magnet, the ohmic heating (OH) coil, which is a four kilovolt magnet that wraps around the TF coil like thread around a bobbin.

“It uses up to 24,000 amps to induce an electric field that drives an electric current within the vessel and helps heat the plasma,” the press release stated.

“These magnets are critical to the NSTX-U experiment, and the team has been laser focused on this assembly,” said Steve Cowley, Laboratory director. “Constructing the first quadrant is a big achievement.”

PPPL states that the quadrants are going through a process called vacuum pressure impregnation (VPI), in which pieces of the TF coil “pie” are baked together into one very tall, solid piece of pie.

The quadrant was made by technicians at Elytt Energy in Bilbao, Spain in July. Further preliminary electrical tests conducted on the quadrant in August showed that the process was successful.

Dave Micheletti, division director of major science and engineering projects, stated that the team is now looking forward to the time “when the entire magnet is complete.”

The NSXT-U recovery team has completed many key components of the nuclear fusion device, once the center stack magnets are installed, the team can begin focusing on reassembling and testing the NSTX-U.

Engineers have designed the TF coil and OH coil so the powerful magnets will be strong enough to confine the plasma during nuclear fusion experiments, which can occur every 20 minutes when the experiment is operating.

The NSTX-U is the primary nuclear fusion experiment at PPPL. The spherical device is shaped more like a cored apple than the doughnut-like shape of conventional tokamaks and can produce high-pressure plasmas — essential ingredients for fusion reactions — with relatively low and cost-effective magnetic fields.

As per PPPL, using both neutral beams and high-power radio waves, the NSTX-U will heat the plasma to 100 million degrees Celsius: seven times hotter than the sun.

Its compact design makes it an ideal candidate to serve as the model for a nuclear fusion pilot plant followed by a commercial fusion reactor, PPPL states.

As of this date, the NSTX-U recovery project is 84 percent complete, and it has seen participation from scientists around the globe.

The end goal is clear – seeking help from around the globe to help PPPL and the world figure out the best way to make commercial nuclear fusion reactors.

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Abhishek Bhardwaj Abhishek brings a wealth of experience in covering diverse stories across different beats. Having contributed to renowned wire agencies and Indian media outlets like ANI and NDTV, he is keenly interested in Tech, Business and Defense coverage.

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