Nuclear rocket propulsion has been investigated for decades, and NASA and the Atomic Energy Commission carried out significant testing in the 1960s as part of the Nuclear Engine for Rocket Vehicle Application program. NERVA chased the potential of the efficiency and energy density of nuclear thermal propulsion to extend our reach to new space frontiers before the program ended in 1973.

You could call it a power contest. Teams picked for a new research program from the Defense Advanced Research Projects Agency (DARPA) will compete to design radiovoltaic cells that can outperform others in measured power density and endure high-flux radiation from a U.S. Army Research Lab linear accelerator. The top teams will strive to make it through a second downselect based on the performance of cells sequestered in time capsules and subjected to even more punishing high-flux radiation. Concepts that make it to the bonus period have a chance to be built into radioisotope-fueled power systems uniquely suited to high-radiation regions of space or dark, remote places on Earth.

Nuclear power already has an energy density advantage over other sources of thermal electricity generation. But what if nuclear generation didn’t require a steam turbine? What if the radiation from a reactor was less a problem to be managed and more a source of energy? And what if an energy conversion technology could scale to fit nuclear power systems ranging from miniature batteries to the grid? The Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) is asking these types of questions in a request for information on High Power Direct Energy Conversion from Nuclear Power Systems, released August 1.

The Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) wants to mimic and accelerate the natural half-life decay chain of alpha-emitting radioisotopes and plans to invite proposals for experimental or theoretical research tracks under Decay on Demand—a new DARPA disruptioneering opportunity. The solicitation was published in draft form on June 27.

Another calendar year has passed. Before heading too far into 2024, let’s look back at what happened in 2023 in the nuclear community. In today's post, compiled from Nuclear News and Nuclear Newswire are what we feel are the top nuclear news stories from January through March 2023.

Stay tuned for the top stories from the rest of the past year.

Ken Petersen
president@ans.org

A big thank-you to the American Nuclear Society Young Members Group for all it accomplished at the Young Professionals Congress (YPC) and President’s Special Session at the 2023 ANS Winter Conference and Expo.

The YPC was held on Saturday, November 11. Its chair, Miriam Kreher, and the YPC planning committee did an excellent job organizing and executing the congress. Its three tracks had something for everyone, including knowledge expansion and soft skills training. The speakers at the congress, including Katy Huff, assistant secretary for nuclear energy, were outstanding in every category.

The President’s Special Session was organized by the Young Members Group (YMG). Matt Wargon, YMG chair, and the planning committee did an incredible job. We kicked around several ideas for a theme before landing on “Space: The [Next] Nuclear Frontier.”

Put nuclear technology in space or on the moon, and just as on Earth it can provide a power density unmatched by any other source. But what roles can nuclear power and propulsion play as the world enters a 21st-century space race? That was a key question put to six speakers during the November 14 American Nuclear Society Winter Meeting plenary session “Space: The (Next) Nuclear Frontier.”

Deploying microreactor technology for military applications could have huge impacts on logistics and reliability for the military of the future, and on the commercial use of similar technologies. That’s why the Department of Defense is developing Project Pele—a high-temperature, gas-cooled and TRISO-fueled microreactor, transportable within mobile shipping containers—for testing at Idaho National Laboratory in 2025.

BWX Technologies announced today that it has been selected to supply the nuclear reactor and fuel for the Defense Advanced Research Projects Agency’s Demonstration Rocket for Agile Cislunar Operations (DRACO) program—the goal of which is to demonstrate a nuclear thermal propulsion (NTP) engine in orbit.

Miguel Alessandro Lopez

At the University of Rhode Island, I initially enrolled as a candidate for an accelerated track to earn bachelor’s and master’s degrees in mechanical engineering, with a minor in nuclear engineering. My objective was to concentrate on reactor power design and join efforts to make nuclear energy safer, more efficient, and less stigmatized.

My plans changed after I attended a guest presentation on high-performance nuclear thermal propulsion (HP-NTP) led by Michael Houts, manager of NASA Nuclear Research at Marshall Space Flight Center. He posted his email address on one of the last slides, so I took a chance and contacted him about potential research opportunities and thesis work. As it turned out, that one little email ultimately led to four NASA-sponsored design projects at URI—two are complete, and two are in progress—as well as my thesis. My research has been on HP-NTP, specifically the centrifugal nuclear thermal rocket (CNTR) design. In that design, liquid uranium is heated to extremely high temperatures in a cylinder that is rotated between 5,000 and 7,000 revolutions per minute as liquid hydrogen passes through the center of the cylinder, where it is heated and expanded, exiting as a propellant while the liquid uranium is retained by centrifugal force.

General Atomics Electromagnetic Systems (GA-EMS) has completed the baseline design of a reactor and engine for a nuclear thermal propulsion (NTP) rocket and has successfully tested key reactor components under contract from the Defense Advanced Research Projects Agency (DARPA), the company announced on November 7. The work was performed under a Track A, Phase 1 contract for the Demonstration Rocket for Agile Cislunar Operations (DRACO) program; Phases 2 and 3 of DRACO could culminate in a demonstration of the nuclear-propelled spacecraft in cislunar space (the region between the Earth and the Moon) during fiscal year 2026.

The Defense Innovation Unit (DIU), a Department of Defense organization focused on swiftly putting commercial technology to use in the U.S. military, has awarded contracts for two nuclear technologies—compact fusion and radioisotope heat—for spacecraft that could carry a high-power payload and freely maneuver in cislunar space. The objective is to accelerate ground and flight testing and launch a successful orbital prototype demonstration of each approach in 2027.

The Department of Defense wants to deploy spacecraft in cislunar space—the area between Earth and the moon’s orbit—with thrust and agility that only nuclear thermal propulsion (NTP) can provide. The Defense Advanced Research Projects Agency (DARPA), through its Demonstration Rocket for Agile Cislunar Operations (DRACO) program, is looking to private industry for the design, development, fabrication, assembly, and testing of a nuclear thermal rocket engine fueled with high-assay low-enriched uranium fuel to heat a liquid hydrogen propellant.

The U.S. Department of Defense is aiming to demonstrate a novel nuclear thermal propulsion (NTP) system above low Earth orbit by 2025. The Defense Advanced Research Projects Agency (DARPA) announced on April 12 that following a competitive solicitation process, it has awarded a contract to General Atomics Electromagnetic Systems (GA-EMS) for the design of the nuclear reactor that will power the Demonstration Rocket for Agile Cislunar Operations (DRACO). Blue Origin and Lockheed Martin will work on a parallel track to design a spacecraft tailor-made to demonstrate the NTP system.

Gates

Bill Gates is making the media rounds to promote his new book, How to Avoid a Climate Disaster: The Solutions We Have and the Breakthroughs We Need, which was released on Tuesday. Along the way, he’s been touting nuclear energy as part of his master plan for battling climate change.

60 Minutes: Gates kicked off the week with an appearance on 60 Minutes on Sunday. During the nearly 15-minute segment with correspondent Anderson Cooper, Gates discussed TerraPower, the company he founded in 2006 that is dedicated to nuclear innovation. “Nuclear power can be done in a way that none of those failures of the past would recur, because just the physics of how it's built,” Gates said, referring to TerraPower’s Natrium reactor. “I admit, convincing people of that will be almost as hard as actually building it. But since it may be necessary to avoid climate change, we shouldn't give up.”