UNIVERSITY PARK, Pa .– Nuclear thermal propulsion, which uses the heat of nuclear reactions for fuel, could one day be used in human spaceflight, possibly even for missions to Mars. Its development, however, poses a challenge. The materials used must be able to withstand high heat and regular bombardment of high energy particles.

Will Searight, a PhD student in nuclear engineering at Penn State, is contributing research that could make these advances more feasible. He has published the results of a preliminary design simulation in Fusion Science and Technology, a publication of the American Nuclear Society.

To further study nuclear thermal propulsion, Searight simulated a small-scale laboratory experiment known as the hydrogen test loop. The setup mimics how a reactor works in space, where circulating hydrogen passes through the core and propels the rocket – at temperatures as high as 2200 degrees Fahrenheit. Searight developed the simulation using the dimensions of the detailed drawings of the link tubes, the components that make up a large part of the test loop through which hydrogen flows. Industrial partner Ultra Safe Nuclear Corporation (USNC) provided the drawings.

“Understanding the behavior of USNC components in a hot hydrogen environment is crucial to getting our rockets into space,” Searight said. “We are delighted to be working with one of the major reactor contractors for the NASA Space Nuclear Propulsion Project, which seeks to produce a demonstration nuclear thermal propulsion engine within a decade.”

Advised by Leigh Winfrey, associate professor and director of the undergraduate program in nuclear engineering, Searight used Ansys Fluent, modeling software, to design a simulation loop from a stainless steel pipe with an outside diameter of d ‘about two inches. In the model, the loop connects to a hydrogen pump and circulates hot hydrogen through a test section adjacent to a heating element.

The hot hydrogen test loop, shown in this diagram, will circulate high temperature hydrogen gas for material testing.

IMAGE: Image provided by Will Searight

Searight discovered that while constant heating of the hydrogen to 2200 degrees Fahrenheit was possible, it was necessary to include a heating element directly above the test section to avoid a reduction in heating. Data collected from the modeling software showed that the flow of hydrogen through the test section was smooth and even, reducing the uneven distribution of heat across the loop which could compromise safety and service life. of the installation. Analysis of the results also verified that stainless steel would allow a more practical and cost effective construction of the loop.

“We are excited to take the first steps in developing a unique capability to simulate extreme environments at Penn State,” said Winfrey. “This preliminary work will allow us to continue research that could have a major impact on the future of space exploration.”

With further research, Searight’s preliminary work could expand the testing of materials that could one day be implemented to create faster and more efficient space travel using jet rockets.

Recently, Searight was awarded the George P. Shultz and James W. Behrens Graduate Scholarship from the ANS. Searight will use the award to support his future work on the test loop. The $ 3,000 scholarship honors Shultz, an advocate for nuclear non-proliferation and recipient of the Presidential Medal of Freedom who died in February, and Behrens, a former ANS board member who has served many positions in the national security sector.

A NASA Small Business Innovation Research contract supported this work.

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Last updated on September 21, 2021