.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ..........

SANTA FE, N.M. — Engineers at Los Alamos National Laboratory had a hand in successfully demonstrating a new concept for a reliable nuclear reactor that could potentially be used by NASA on missions to space.

The experiment recently conducted at the Nevada National Security Site’s Device Assembly Facility near Las Vegas confirmed that heat pipe technology, first invented at Los Alamos in 1963, and basic nuclear reactor physics could be used to cool a small nuclear reactor and power an engine.

“This particular system is for outer planet science missions,” explained David Poston, LANL’s lead engineer on the project. “NASA has been using plutonium power since the 1960s, and this will provide more capabilities and higher powers to enhance deep space capability.”

ADVERTISEMENTSkip

................................................................

Before going too deep into space, Poston said NASA would likely use the technology closer to home on missions to the moon or Mars.

“The only way we get this in line is with small steps,” Poston said.

Poston said NASA has experimented a lot with using solar power for its missions into space, but that presents problems on the moon, which is in Earth’s shadow for 14 days at a time. Storms and the planet’s distance from the sun makes solar power a less practical option for missions to Mars.

“So nuclear power has been recognized as the preferred option,” Poston said. “This fills a niche that NASA needs and it’s very simple.”

It works with a heat pipe, a sealed tube with an internal fluid that can transfer heat produced by a reactor with no moving parts, and a Stirling engine, a closed-loop engine that converts heat energy into electrical power by using pressurized gas to move a piston. Using the two devices in tandem created what researchers say is a reliable electric power supply.

“We hope that this proof of concept will soon move us from the old frontier of Nevada to the new frontier of outer space,” LANL project leader Patrick McClure said in a press release.

Engineers from LANL, the NASA Glenn Research Center and National Security Technologies tested it on an existing experiment called “Flattop.” Los Alamos nuclear engineers operated the Flattop assembly that allowed for a water-based heat pipe to extract heat from uranium. Heat from the fission reaction was then transferred to a pair of Stirling engines.

The Demonstration Using Flattop Fissions, or DUFF, produced just 24 watts of electricity. But Poston said the mechanism is capable of a much higher output. Facility regulations at the test site limited the amount that could be used for the experiment.

“Our flight system concept uses eight modules and each produces 90 watts. So if you do the math, you come up with close to 700 watts,” he said. “Frankly, going to a kilowatt, or 1.5 kilowatts, is not much of a technology stretch.”

Poston said the nuclear characteristics and thermal power level of the experiment are remarkably similar to LANL’s space reactor flight concept.

“The biggest difference between the DUFF and a possible flight system is that the Stirling input temperature would need to be hotter to attain the required efficiency and power output needed for space missions,” he said.

Poston said there’s no technical reason why hotter input temperatures couldn’t be produced, but it would probably require a different type of Stirling engine.

The next evolution of the prototype would be nuclear thermal propulsion for rocket thrusters, Poston said. Such a mechanism could render rockets capable of powering payloads to Mars much quicker, he said.

“NASA’s considering funding the next step,” he said, adding that the prototype would need to be capable of handling higher temperatures. “We’re in the midst of coming up with what that would look like.”

Poston said LANL engineers could be ready to start as soon as January, “but budgeting is always a big factor.”

LANL engineer David Dixon said the research team proved through the experiment that advancing the concept could be done efficiently.

“Perhaps one of the more important aspects of this experiment is that it was taken from concept to completion in six months for less than a million dollars,” he said. “We wanted to show that with a tightly knit and focused team, it is possible to successfully perform practical reactor testing.”