January 3, 2017


Fusion energy: a time of transition and potential (Stewart Prager, 1/02/17, Cosmos)

From here, the remaining path toward fusion power has two components. First, we must continue research on the tokamak. This means advancing physics and engineering so that we can sustain the plasma in a steady state for months at a time. We will need to develop materials that can withstand an amount of heat equal to one-fifth the heat flux on the surface of the sun for long periods. And we must develop materials that will blanket the reactor core to absorb the neutrons and breed tritium.

The second component on the path to fusion is to develop ideas that enhance fusion's attractiveness. Four such ideas are:

1) Using computers, optimize fusion reactor designs within the constraints of physics and engineering. Beyond what humans can calculate, these optimized designs produce twisted doughnut shapes that are highly stable and can operate automatically for months on end. They are called "stellarators" in the fusion business.

2) Developing new high-temperature superconducting magnets that can be stronger and smaller than today's best. That will allow us to build smaller, and likely cheaper, fusion reactors.

3) Using liquid metal, rather than a solid, as the material surrounding the plasma. Liquid metals do not break, offering a possible solution to the immense challenge how a surrounding material might behave when it contacts the plasma.

4) Building systems that contain doughnut-shaped plasmas with no hole in the center, forming a plasma shaped almost like a sphere. Some of these approaches could also function with a weaker magnetic field. These "compact tori" and "low-field" approaches also offer the possibility of reduced size and cost.

Government-sponsored research programs around the world are at work on the elements of both components - and will result in findings that benefit all approaches to fusion energy (as well as our understanding of plasmas in the cosmos and industry). In the past 10 to 15 years, privately funded companies have also joined the effort, particularly in search of compact tori and low-field breakthroughs. Progress is coming and it will bring abundant, clean, safe energy with it.

Posted by at January 3, 2017 5:33 AM