Controlled Nuclear Fusion

In the past I posted an idea regarding a possible way to scale up a device called a “fusor”, a small hydrogen fusion reactor that uses electrostatic forces to accelerate deuterium ions towards the center of the device where a portion of them collide with sufficient energy to fuse releasing neutrons, helium, and energy.

These devices have been around for many years but they only generate a very small amount of energy and consume more energy than they produce. They are useful as neutron sources.

Conventional fusors consist of two concentric grids inside a vacuum vessel to create an electrostatic field gradient to accelerate deuterium ions. The difficulty with this approach is that a large number of ions collide with the inner grid heating the grid and melting it before a usable amount of power can be generated.

My thought was to operate the fusor not as a steady state device but rather as an AC field device such that the charge on the inner grid reverses just as the ions pass it, avoiding collisions.

Dr. Robert W. Bussard came up with another idea to eliminate losses to the grids. He eliminated the grids. Instead of using grids to create the electrostatic field, he has come up with a magnetic means of containing electrons to create a potential well.

Personally, I find Dr. Bussard a bit annoying because he feels the need to attack any competing approaches such as Tokamak, never the less I find his approach interesting and promising.

Here is a video presentation by Dr. Bussard on his machine. It’s an interesting talk if you discount his trashing Tokamak fusion. The large size required for a Tokamak and cost really doesn’t represent a big issue in a nuclear power generating situation because you are talking about power levels of 600 megawatts or more an a large machine is required just for heat load considerations.

The video describes the evolution of the machines they built and how they kept addressing various issues with each generation and eventually on the last attempt created a machine that produced fusions at 100,000 times the maximum achieved by Farnsworth with his fusor. At that point they ran out of funding.

My feelings on the Tokamak reactors, particularly the spherical Tokamak reactors have the ability to make power commercially economically, the majority of the science is done for Tokamak reactors and the scaling laws are known. They will be too large to be used in portable applications such as powering trains and planes and ships and spacecraft.

This technology is not quite as ready but this system may be able to work for these applications. They believe that at a size of 2-1/2 meters these can produce power even with a PB11-proton system which is aneutronic (produces all charged particles, no neutrons). A deuterium-tritium system can be around 1-1/2 meters. Still too big for a DeLorean but small enough for large aircraft, ships, trucks, trains, and spacecraft.

The spacecraft applications are incredible, this technology could make trips to Mars and even outer planets practical.

Category: Future

Leave a Reply