Foundational Stronger Magnet Made by Commonwealth Fusion Systems

Commonwealth Fusion Systems and MIT’s Plasma Science and Fusion Center (PSFC) have demonstrated a magnet with a record-breaking 20 Tesla magnetic field. This is the core technology that they planned to create. They now have to mass produce it at ten times lower cost and assemble it into a net energy gain system by 2025. They have $200 million in funding from Bill Gates and many other funds and investors. The 20 Tesla magnets will make the Commonwealth Fusion reactor 40 times smaller than the ITER tokamak reactor which will use 11-tesla magnets.

The 20 Tesla magnets will be used in SPARC, which is on track to begin construction in 2021 and demonstrate net energy gain from fusion for the first time in history by 2025. SPARC will pave the way for the first commercially viable fusion power plant called ARC.

A 19 Tesla field is powerful enough to life 403 Boeing 747s. It has 166 miles of superconducting tape.

Commonwealth Fusion is trying to make a compact Tokomak with more powerful superconducting magnets. They wanted a commercial tokamak by 2033 but the current target is 2035 for a commercial tokamak. MIT spunout a tokamak fusion project into Commonwealth Fusion systems. They want to apply modular designs to high-temperature superconductors. They want to get to stronger magnets that will shrink the size and cost of the potential nuclear fusion reactor. Improved magnets would improve any nuclear fusion design that involves confinement of plasma. There is less science risk to this MIT approach but more technological risk. They are trying to accelerate the commercial use of high-temperature superconducting magnets and trying to contain their costs. Cost for superconducting magnets for past fusion projects have been $20 per watt but other applications have seen costs of $1.4 to $1.8 per watt.

They want to mass produce superconducting magnets that are 2X the field strength of past strong magnets while bringing the cost per watt down.

The list of items below that Commonwealth fusion is targeting is from 2018.

There are 16 subsegments stacked for each magnet and 18 magnets are needed for the demo net gain system.

Commonwealth Fusion has more detailed project plans and peer-reviewed papers indicate the science is sound.

SPARC will use new high temperature superconducting (HTS) magnets to enable a similar performance as ITER but built more than 10 times smaller and on a significantly faster timeline.

The papers also predict that SPARC will very likely achieve a burning plasma for the first time on earth, meaning the fusion process will be dominantly self-heating. This is a major multi-decade goal of the world’s scientific community. In 2020, Commonwealth Fusion Systems (CFS) had a series of seven papers published and peer reviewed in a special edition of the Journal of Plasma Physics validating CFS’ approach to commercial fusion energy.

NOTE: Two years ago Tokamak Energy reported progress on a 20 Tesla magnet.The Commonwealth Fusion System 20 Tesla magnet is more complete for a fusion project. There are also more powerful magnets at the National Magnet lab. There is a 32 Tesla superconducting magnet. 42 Tesla hybrid magnet and 100 Tesla pulse magnet. Those magnets are for lab work and would be suitable for the Tokamak project.

SOURCES – Commonwealth Fusion Systems, Journal of Plasma Physics
Written By Brian Wang,