Detailed study of high-temperature superconducting magnets built by MIT and Commonwealth Fusion Systems confirms they meet requirements for an economic, compact fusion power plant. In the predawn hours of September 5, 2021, engineers achieved a major milestone in the labs of MIT’s Plasma Science
TLDR: New REBCO superconductor can operate with significantly less insulation, allowing them to be built much smaller. Thereby making critical space for other components.
From the article:
“The standard way to build these magnets is you would wind the conductor and you have insulation between the windings, and you need insulation to deal with the high voltages that are generated during off-normal events such as a shutdown.” Eliminating the layers of insulation, he says, “has the advantage of being a low-voltage system. It greatly simplifies the fabrication processes and schedule.” It also leaves more room for other elements, such as more cooling or more structure for strength.
Not Mr. Fusion, but a modest industrial facility that could fit in an industrial park rather than the very large ITER which has its own complex. The ARC reactor design from commonwealth fusion is expected to have a major radius of 3.3m whereas ITER has a major radius of 6.2m. That might not sound like a big difference, but material costs and supporting systems cost roughly scale with volume which is a factor of 8 difference.
Here's an old, but good talk on the motivation for this proof of concept. I linked the most relevant time, but the entire presentation is worth watching if you find it interesting.
Personally, I find this success to be way more exciting than the NIF breakeven shots. Those were neat milestones, but don't get us closer to a feasible commercial design. This REBCO magnet demonstration makes commercial fusion a possibility in a timescale that could matter.
Looks like we've been making this stuff since 2006 and at decent enough volumes since then.
About 10 km of REBCO was delivered
by SuperPower that year in the world’s first manufacturing
demonstration to construct a 30 m long power transmission
cable that was installed in the power grid
20 kelvins. It’s “high temperature” but only compared to the usual 4 kelvins needed in previous designs. (This isn’t another sketchy “room temperature” superconductor claim where the media is going to go ape shit and then we’re all going to be disappointed in a few weeks.)