Metal frameworks could capture krypton-85 during reprocessing

Image: Purdue University/Maria Okuniewski

A team of researchers led by Purdue University has used X-ray imaging conducted at Argonne National Laboratory’s Advanced Photon Source to obtain a three-dimensional view of the interior of an irradiated nuclear fuel sample. The use of synchrotron micro-computed tomography could lead to more accurate modeling of fuel behavior and more efficient nuclear fuel designs, according to the researchers.

In this AI-designed layout for a boiling water reactor, fuel rods are ideally positioned around two fixed water rods to burn more efficiently. MIT researchers ran the equivalent of 36,000 simulations to find the optimal configurations. Colors correspond to varying amounts of uranium and gadolinium oxide in each rod. Image: Majdi Radaideh/MIT

Researchers at the Massachusetts Institute of Technology and Exelon show that by turning the nuclear fuel assembly design process into a game, an artificial intelligence system can be trained to generate dozens of optimal configurations that can make each fuel rod last about 5 percent longer, saving a typical power plant an estimated $3 million a year, the researchers report.

The AI system can also find optimal solutions faster than a human and can quickly modify designs in a safe, simulated environment. The results appear in the journal Nuclear Engineering and Design.

Designs chosen for ARC-20 support could be commercialized in the mid-2030s. Graphic: DOE

The Department of Energy’s Office of Nuclear Energy (DOE-NE) has named the recipients of $20 million in Fiscal Year 2020 awards for Advanced Reactor Concepts–20 (ARC-20), the third of three programs under its Advanced Reactor Demonstration Program (ARDP). The three selected teams—from Advanced Reactor Concepts LLC, General Atomics, and the Massachusetts Institute of Technology—will share the allocated FY20 funding for ARC-20 and bring the total number of projects funded through ARDP to 10. DOE-NE announced the news on December 22.

The DOE expects to invest a total of about $56 million in ARC-20 over four years, with industry partners providing at least 20 percent in matching funds. The ARDP funding opportunity announcement, issued in May 2020, included ARC-20 awards, Advanced Reactor Demonstration awards, and Risk Reduction for Future Demonstration awards.

Terrestrial Energy and the Nuclear Research and Consultancy Group (NRG) have started a graphite irradiation testing program at NRG’s Petten Research Centre’s High Flux Reactor (HFR), located in the Netherlands. According to Terrestrial Energy, which is based in Ontario, Canada, the work is part of broader program of confirmatory testing of components and systems for the company’s Integral Molten Salt Reactor (IMSR), designed to produce both electricity and industrial heat.

The testing program at NRG was planned to confirm the predicted performance of selected graphite grades throughout the seven-year cycle of an IMSR core. The testing was designed in cooperation with Frazer-Nash Consultancy, and will simulate IMSR core conditions at a range of operating temperatures and neutron flux conditions.

“Our work with NRG at its Petten HFR facility is an important element of our overall IMSR test program, now well underway. The start of in-core irradiation tests speaks to our progress and comes after many months of prior work,” Simon Irish, CEO of Terrestrial Energy, said on November 12. “The NRG work also reflects an important feature of our testing strategy. That is to engage existing laboratories offering existing capabilities rather than build those in-house, a strategy that is essential for our early deployment schedule.”

An MIT-led team found that the formulas describing how atoms behave in a gas can be generalized to predict how protons and neutrons interact at close range. Image: Collage by MIT News. Neutron star image: X-ray (NASA/CXC/ESO/F.Vogt et al); Optical (ESO/VLT/MUSE & NASA/STScI)

In an MIT News article playfully titled “No matter the size of a nuclear party, some protons and neutrons will always pair up and dance,” author Jennifer Chu explains that findings on the interactions of protons and neutrons recently published in the journal Nature Physics show that the nucleons may behave like atoms in a gas.

A Massachusetts Institute of Technology–led team simulated the behavior of nucleons in several types of atomic nuclei using supercomputers at Los Alamos National Laboratory and Argonne National Laboratory. The team investigated a range of nuclear interaction models and found that formulas describing a concept known as contact formalism can be generalized to predict how protons and neutrons interact at close range.

You may have read the abbreviated version of this article in the November 2020 issue of Nuclear News. Now here's the full article—enjoy!

I have enjoyed a long and stimulating career in applied nuclear physics—specifically nuclear reactor physics, nuclear fusion plasma physics, and nuclear fission and fusion reactor design—which has enabled me to know and interact with many of the scientists and engineers who have brought the field of nuclear energy forward over the past half-century. In this time I have had the fortune to interact with and contribute (directly and indirectly) to the education of many of the people who will carry the field forward over the next half-century.

Two projects intended to accelerate the deployment of hydrogen production technology at existing U.S. light-water reactors received the bulk of the funding announced by the Department of Energy’s Office of Nuclear Energy (NE) on October 8 under the ongoing U.S. Industry Opportunities for Advanced Nuclear Technology Development funding opportunity announcement (FOA). Out of three projects with a total value of $26.9 million, the two involving hydrogen production have a total value of $26.2 million.

Cutaway of the SPARC engineering design. Image: CFS/MIT-PSFC, CAD rendering by T. Henderson

Seven open-access, peer-reviewed papers on the design of SPARC, Commonwealth Fusion Systems’ (CFS) fusion tokamak, written in collaboration with the Massachusetts Institute of Technology’s Plasma Science and Fusion Center, were published on September 29 in a special edition of the Journal of Plasma Physics.

The papers describe a compact fusion device that will achieve net energy where the plasma generates more fusion power than used to start and sustain the process, which is the requirement for a fusion power plant, according to CFS.

The timeline for this planned device sets it apart from other magnetic confinement fusion tokamaks: Construction is to begin in 2021, with the device coming on line in 2025.

CFS expects the device to achieve a burning plasma—a self-sustaining fusion reaction—and become the world’s first net energy (Q>1) fusion system. The newly released papers reflect more than two years of work by CFS and the Plasma Science and Fusion Center to refine their design. According to CFS, the papers apply the same physics rules and simulations used to design ITER, now under construction in France, and predict, based on results from existing experiments, that SPARC will achieve its goal of Q>2. In fact, the papers describe how, under certain parameters, SPARC could achieve a Q ratio of 10 or more.

Cutaway of the SPARC engineering design. Image: CFS/MIT-PSFC, CAD Rendering by T. Henderson

A special issue of the Journal of Plasma Physics gives a glimpse into the physics basis for SPARC, the DT-burning tokamak being designed by a team from the Massachusetts Institute of Technology and Commonwealth Fusion Systems. The special issue was announced in a September 29 post on the Cambridge University Press blog Cambridge Core.

The special JPP issue includes seven peer-reviewed articles on the SPARC concept, which takes advantage of recent breakthroughs in high-temperature superconductor technology to burn plasma in a compact tokamak design.

TerraPower announced on September 15 that it plans to work with Centrus Energy to establish commercial-scale production facilities for the high-assay, low-enriched uranium (HALEU) needed to fuel many advanced reactor designs.

The proposed investment in HALEU fuel fabrication is tied to a TerraPower-led submittal to the Department of Energy’s Advanced Reactor Demonstration Program (ARDP), which was created to support the deployment of two first-of-a-kind advanced reactor designs within five to seven years. TerraPower would like one of those designs to be Natrium, the 345-MWe sodium fast reactor that it has developed with GE Hitachi Nuclear Energy.