Although to most the term ‘fission reactor’ brings to mind something close to the commonly operated light-water reactors (LWRs) which operate using plain water (H2O) as coolant and with sluggish, thermal neutrons, there are a dizzying number of other designs possible. Some of these have been in use for decades, like Canada’s heavy water (D2O) reactors (CANDU), while others are only now beginning to take their first step towards commercialization.
These include helium-cooled, high-temperature reactors like China’s HTR-PM, but also a relatively uncommon type developed by Terrestrial Energy, called the Integral Molten Salt Reactor (IMSR). This Canadian company recently passed phase 2 of the Canadian Nuclear Safety Commission’s (CNSC) pre-licensing vendor review. What makes the IMSR so interesting is that as the name suggests, it uses molten salts: both for coolant and the low-enriched uranium fuel, while also breeding fuel from fertile isotopes that would leave an LWR as part of its spent fuel.
So why would you want your fuel to be fluid rather than a solid pellet like in most reactors today?
Continue reading “The Integral Molten Salt Reactor And The Benefits Of Having A Liquid Fission Reactor”
It’s hardly a secret that nuclear fusion has had a rough time when it comes to its image in the media: the miracle power source that is always ‘just ten years away’. Even if no self-respecting physicist would ever make such a statement, the arrival of commercial nuclear fusion power cannot come quickly enough for many. With the promise of virtually endless, clean energy with no waste, it does truly sound like something from a science-fiction story.
Meanwhile, in the world of non-fiction, generations of scientists have dedicated their careers to understanding better how plasma in a reactor behaves, how to contain it and what types of fuels would work best for a fusion reactor, especially one that has to run continuously, with a net positive energy output. In this regard, 2020 is an exciting year, with the German Wendelstein 7-X stellarator reaching its final configuration, and the Chinese HL-2M tokamak about to fire up.
Join me after the break as I look into what a century of progress in fusion research has brought us and where it will take us next.
Continue reading “Nuclear Fusion At 100: The Hidden Race For Energy Supremacy”
Rockets with nuclear bombs for propulsion sounds like a Wile E. Coyote cartoon, but it has been seriously considered as an option for the space program. Chemical rockets combust a fuel with an oxidizer within themselves and exhaust the result out the back, causing the rocket to move in the opposite direction. What if instead, you used the higher energy density of nuclear fission by detonating nuclear bombs?
Detonating the bombs within a combustion chamber would destroy the vehicle so instead you’d do so from outside and behind. Each bomb would include a little propellant which would be thrown as plasma against the back of the vehicle, giving it a brief, but powerful push.
That’s just what a group of top physicists and engineers at General Atomic worked on between 1958 and 1965 under the name, Project Orion. They came close to doing nuclear testing a few times and did have success with smaller tests, exploding a series of chemical bombs which pushed a 270-pound craft up 185 feet as you’ll see below.
Continue reading “Project Orion: Detonating Nuclear Bombs For Thrust”