[Tech Talk] Can 'Chojondo Tape' Realize the Dream of Nuclear Fusion?

Skepticism Grows in International LK-99 Academic Community
But 'High-Temperature Superconductor' Technology Continues to Advance
Operates at -180 Degrees, Higher than Absolute Zero

As international skepticism grows regarding the superconducting material 'LK-99' discovered by domestic researchers, the dream of room-temperature and ambient-pressure superconductors seems to be drifting further away. However, superconducting technology has not been stagnant over the past several decades.

Research institutes specializing in condensed-matter physics located in the United States, the United Kingdom, and elsewhere have long been dedicated to developing superconductors that operate at relatively high temperatures. Recently, they have succeeded in mass-producing 'superconducting tapes.' If successful, this material could accelerate the commercialization timeline of nuclear fusion power generation.

Steady Progress in Superconductors Over Decades

Superconductor. [Image source=University of Rochester]

In fact, high-temperature superconductors (HTS) already exist. However, the 'high temperature' of superconductors is much lower than what the general public would consider high.

Generally, materials exhibiting superconductivity need to be cooled close to absolute zero (minus 273 degrees Celsius) for the superconducting phase transition to occur, but some materials can undergo this transition at much higher temperatures.

For example, the yttrium-barium-copper oxide (YBCO) superconductor exhibits superconductivity near minus 180 degrees Celsius. Such materials are currently classified as HTS by the academic community.

HTS Tapes Operating at Minus 180 Degrees

YBCO high-temperature superconducting tape jointly developed by Commonwealth Fusion and the MIT Plasma Science and Fusion Center. [Image source=MIT]

Minus 180 degrees Celsius is still quite impractical for everyday use. However, given the current difficulty in developing room-temperature and ambient-pressure superconductors, these materials remain the most economical and commercially viable option.

In particular, several startups developing nuclear fusion reactors are focusing on these HTS materials. For instance, Commonwealth Fusion, a nuclear fusion power plant development company spun off from the Massachusetts Institute of Technology (MIT), is one of the first companies to create superconducting electromagnets using YBCO superconductors in tape form.

Superconducting tape refers to a material coated with a superconducting alloy on a tape substrate. Commonwealth Fusion produced an astonishing 10,000 square kilometers of this superconducting tape and wound it into a 'D' shape to create electromagnets. These superconducting electromagnets operate at relatively higher temperatures (around minus 200 degrees Celsius) compared to conventional superconductors and can generate magnetic fields as strong as 20 teslas (T).

Electromagnets are key components of nuclear fusion reactors and also one of the major hurdles to the commercialization of nuclear fusion. Typically, nuclear fusion reactors generate plasma at temperatures of 100 million degrees Celsius to produce electricity, and superconducting electromagnets are essential for stabilizing this plasma by confining it with magnetic fields. It is known that a magnetic field strength of approximately 20T is required to stabilize a tokamak.

Multiple Candidates Like YBCO and REBCO... Could They Be the Key to Nuclear Fusion?

REBCO high-temperature superconducting tape from Tokamak Energy, UK. Although these superconducting tapes do not operate at room temperature, they can function at much higher temperatures than conventional superconductors, specifically between -200 and -180 degrees Celsius.
[Image source=Tokamak Energy]

There are other candidate superconducting tapes as well. Another high-temperature superconductor known to exhibit superconducting phase transitions between minus 200 and minus 180 degrees Celsius is rare-earth barium copper oxide (REBCO).

The UK-based nuclear fusion startup Tokamak Energy has been focusing on the potential of REBCO-based superconducting tapes.

Recently, Tokamak Energy succeeded in developing a prototype of REBCO superconducting tape and plans to produce a superconducting electromagnet called 'Demo 40' within this year. The cooling efficiency of Demo 40 is reportedly about five times higher than that of existing superconductors.

If Room-Temperature Superconductors Existed... Nuclear Fusion Could Become a Reality Sooner

When news first spread that LK-99 might be a superconductor operating at room temperature and ambient pressure, prominent nuclear fusion researchers responded positively.

Andrew Coates, a Canadian nuclear fusion researcher who was part of General Fusion?a nuclear fusion startup famously backed by Jeff Bezos, the founder of Amazon?predicted, "If LK-99 is real, its economic impact could reach up to $4.5 trillion (approximately 5,900 trillion won)."

If a material exists that undergoes superconducting phase transitions at room temperature, it would be possible to confine plasma in nuclear fusion reactors without cooling down to minus 200 degrees Celsius. This would allow the power output of fusion reactors to easily surpass the power consumption required to maintain the plasma.

Despite decades of alternating hope and failure, humanity has not abandoned the dream of room-temperature and ambient-pressure superconductors.