Penn State Breazeale Reactor achieves first simultaneous neutron beam operations

Technical upgrades enable concurrent operations for five neutron beam ports, allowing for 13 operations at once

November 17, 2022

By Ashley WennersHerron

UNIVERSITY PARK, Pa. — The Penn State Breazeale Reactor is the country’s first licensed and longest continuously operating nuclear research reactor, and now it is one of the most productive. Thanks to a $1.35 million grant from the U.S. Department Energy (DOE) for a new core moderator assembly and beam port installations and the College of Engineering’s $9.5 million investment in a 10,000-square-foot beam hall expansion and several technical upgrades the investment facilitated, the reactor can now run five beam ports with seven neutron beam lines simultaneously.  

Beam ports are the hollow tubes through which neutron beams travel from the reactor core to the point of experimental investigation. The more active beam ports there are, the more experiments researchers can run at once. The research reactor — which runs at a lower power to produce neutrons than a power reactor that generates electricity — was established in 1955 and has never operated all of the beam ports simultaneously until now. 

“Due to inherited design issues since 1965 with the arrangement of beam ports and reactor core-moderator assembly, the development of innovative experimental facilities utilizing neutron beams was extremely limited,” said Kenan Ünlü, director of the Radiation Science & Engineering Center (RSEC), which houses the reactor, and professor of nuclear engineering said. “I started working to change these arrangements as soon as I joined Penn State in 2002. Three doctoral students and two master of science students earned their degrees on the project. We developed the optimal design for the maximum neutron output for each beam port. Once we obtained the needed funding from DOE, we implemented it in 2018.” 

Prior to 2018 installation, scientists could only use one beam port, limiting the number and kind of experiments they could conduct. The reactor core produced neutrons via fission reactions, which then traveled through a heavy water tank and were carried by neutron beam ports outside of the reactor’s biological shields to the experimental site. Researchers then examined if and how the neutrons interacted to reveal information about the sample. 

Now, the mechanics are similar but researchers can do more by utilizing all of the new beam ports simultaneously, according to Jeffrey Geuther, associate director for operations in RSEC and associate research professor of nuclear engineering. 

“With multiple upgrades and several technical advancements, we overcame the previous challenges,” Geuther said. “By simultaneously running all five beam ports with seven beam lines, we can now operate the reactor at full power while accessing all beam port experimental facilities, and six in-core irradiation locations.”  

According to Daniel Beck, engineering program manager at RSEC, three of the five beam ports were recently equipped with a new neutron imaging facility, a neutron absorber measurements facility and a flexible thermal neutron beam facility with sapphire filters, collimators and adjustable apertures for exploratory research projects. 

“By upgrading the beam ports and experimental facilities, researchers can access different beam lines allowing for a variety of experimental conditions,” Beck said.  

Upgrades planned for 2023, including the installation of a cold neutron source and supermirror neutron guides, will enable three additional neutron beam lines. One of the cold neutron beam lines will be designated for the small-angle neutron scattering (SANS) facility — a $9.8 million equipment donation from Helmholtz-Zentrum Berlin in Germany — that will be shipped to Penn State next year. According to Ünlü, the Breazeale Reactor will be the only university research reactor with the SANS capability in the United States.

“We also recently upgraded the reactor’s digital control system and installed a new cobalt-60 source into the gamma irradiation pool at RSEC,” Geuther said, noting that these upgrades will expand research capabilities even further. “The immediate impact of the improved and new experimental facilities will be felt campus-wide, increasing faculty and student involvement in RSEC and the reactor to conduct cutting-edge research primarily in materials, chemistry, physics and biological sciences.”

The new and planned capabilities at the reactor will provide an “excellent” test bed for researchers from industry, national laboratories and other universities, according to Ünlü. The beam hall expansion will help support the increased research needs, with space for faculty and students in the Penn State Ken and Mary Alice Lindquist Department of Nuclear Engineering and visitors. 

“It is an exciting time for neutron science at Penn State, especially as we further strengthen our ties with national laboratories and research centers around the world,” Ünlü said. “The new and improved facilities will open new horizons for neutron science at Penn State.” 


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College of Engineering Media Relations

“It is an exciting time for neutron science at Penn State, especially as we further strengthen our ties with national laboratories and research centers around the world." — Kenan Ünlü