Tuesday, December 12, 2017

Only Sixty Years Late: Nazi Designed Reactors In Space

newatlas | "The reactor technology we are testing could be applicable to multiple NASA missions, and we ultimately hope that this is the first step for fission reactors to create a new paradigm of truly ambitious and inspiring space exploration," says David Poston, Los Alamos' chief reactor designer. 
"Simplicity is essential to any first-of-a-kind engineering project – not necessarily the simplest design, but finding the simplest path through design, development, fabrication, safety and testing."

Rated at 10 kilowatts, the Kilopower reactor puts out enough power to support two average American homes and can run continuously for ten years without refueling. Instead of plutonium, it uses a solid, cast uranium 235 reactor core 6 inches (15 cm) in diameter. This is surrounded by a beryllium oxide reflector with a mechanism at one end for removing and inserting a single rod of boron carbide. This rod starts and stops the reactor while the reflector catches escaping neutrons and bounces them back into the core, improving the efficiency of the self-regulating fission reaction. Until activated, the core is only mildly radioactive.

The heat from the reactor is collected and transferred using passive sodium heat pipes. These feed the heat to a set of high-efficiency Stirling engines. These are closed-loop engines that run on heat differences that cause a piston to move back and forth similar to the piston in an internal combustion engine, though with a compressible gas medium instead of an exploding mixture of petrol and air. This cools the reactor via a radiator umbrella as well as powering a dynamo to generate electricity.

The design is modular, so the self-contained reactor units can be hooked together to provide as much power as needed, whether it's a deep space probe or a Martian outpost. According to Lee Mason, STMD's principal technologist for Power and Energy Storage at NASA Headquarters, the technology is "agnostic" to its environment, allowing it a wide range of applications.

The Kilopower project is currently working toward a full-power test lasting about 28 hours. From there, NASA hopes to move to a test in space, but the Nevada tests are more of a breadboard test in a vacuum to show that the technology is feasible. 

"What we are striving to do is give space missions an option beyond RTGs, which generally provide a couple hundred watts or so, says Mason says. "The big difference between all the great things we've done on Mars, and what we would need to do for a human mission to that planet, is power. This new technology could provide kilowatts and can eventually be evolved to provide hundreds of kilowatts, or even megawatts of power. We call it the Kilopower project because it gives us a near-term option to provide kilowatts for missions that previously were constrained to use less. But first things first, and our test program is the way to get started."