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At least 181 records · Page 10

Development of Innovative Measurement Techniques for Fission Product Transport Quantification

This document provides the progress of a research project at Texas A&M University (TAMU), led by Idaho National Laboratory (INL), in support of the Versatile Test Reactor (VTR) program and work scope area of gas-cooled fast reactors. The VTR TAMU INL project started in October 2018. The document includes the main objectives of the project, scaling analysis applied to the experimental facilities, experimental methodology including instrumentation and techniques applied, and up-to-date results from the experimental and numerical studies.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Improving Fission Products at CARIBU: Near Field Detection (Q3/FY20 Quarterly Progress Report)

Following the report from last quarter where we reported the experimental procedures, data acquisition and filtering process for the beta decay of 156 Eu, in the past quarter we have worked on establishing the efficiency for detecting the radiation emitted from this isotope with simulations of the HPGe detector and we have started investigating the beta detector energy deposition spectra.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Improving Fission Products at CARIBU: Near Field Detection (Q1/FY21 Quarterly Progress Report)

After receiving funds at the beginning of FY21 we were able to resume work on the project. We continued data analysis of 156 Eu decay. The project has also gone through an Independent Review in November. Following the previously reported steps in the analysis of 156 Eu, specifically removing random coincidences from the gamma ray spectrum, we look not only at the peak of interest (811 keV) but all other gamma rays that are visible. Determining the area of all gamma ray peaks in this random coincidence free spectrum is not only necessary to calculate the gamma ray branching ratios but combined with the peak areas of the gamma ray singles spectrum we are able to determine experimentally the efficiency of the beta detector.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Improving Fission Products at CARIBU: Near Field Detection (Q3/FY21 Quarterly Progress Report)

The overview of our project as well as most recent results have been presented at the NSARD review in April, and more recently during the WoNDRAM workshop. We have been dealing with recent personnel changes in the group. Miguel Bencomo, who has worked with us on this project as a postdoc at LLNL since 2019, will be terminating his appointment within the next two weeks to take a full-time appointment with Raytheon. We continue training our new team member Dan Hoff to take over data analysis from the last experiment we performed, as well as prepare for upcoming measurements. Additionally, we are working with a summer student, John Wilkinson, who is training to perform GEANT4 simulations of beta detector this summer.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Fission-product decay studies with the FRIB Decay Station

The Facility for Rare Isotopes Beams (FRIB) will be the flagship facility in low-energy nuclear physics when it comes online in 2022. This U.S. Department of Energy Office of Science user facility will open up a multitude of new opportunities to study exotic nuclei and will lead to new discoveries in nuclear structure, nuclear astrophysics, fundamental symmetries, and isotopes of importance to nuclear applications. The b-decay properties of neutron-rich isotopes will be measured with the FRIB Decay Station, a sophisticated state-of-the-art modular multi-detector system envisioned to perform b, g, n, and charged-particle spectroscopy. In this feasibility study, we use nuclear decay data collected with the FRIB Decay Station precursor, the Beta-Counting Station, currently used at Michigan State University with a radioactive beam produced at the National Superconducting Cyclotron Laboratory to identify the FRIB Decay Station capabilities for future measurements of neutron-rich exotic nuclei at FRIB to help provide a path forward for future measurements of interest to the lab’s mission.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Improving Fission Products at CARIBU: Near Field Detection (Q4/FY21 Quarterly Progress Report)

Since the last quarterly, we have been working on improving the GEANT4 simulation model, which we currently use for the 4-pi gas counter efficiency calculations, to streamline the work when calculating multi-level decay properties. We have also been preparing for the next branching-ratio measurement, which will be for 161 Tb. Because travel is still limited and restricted, we have worked with a summer student on performing simulations to estimate our detector’s efficiency for different thresholds.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Improving Fission Products at CARIBU: Near Field Detection (Q4/FY22 Quarterly Progress Report)

The beamtime at ANL that was originally scheduled to start on August 12 th was delayed until October due to issues with the CARIBU gas catcher. The repair of the catcher has taken a few weeks but was successful. In preparation for our upcoming measurement, we travelled to Texas A&M to set up and characterize our detection system.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Improving Fission Products at CARIBU: Near Field Detection (Q1/FY23 Quarterly Progress Report)

We performed a branching ratio measurement of the most intense gamma rays in the decay of 111Ag. The sample was harvested at Argonne National Laboratory and measured at Texas A&M with the same technique as we used in our previous measurements. We made two samples and were able to measure both of them. The data is currently under analysis.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Improving Fission Products at CARIBU: Near Field Detection (Q2/FY23 Quarterly Progress Report)

We continue work on the 111 Ag analysis which is currently close to being complete. We received referee comments after submission of the mass measurement results for 128 Sb to Phys. Rev. Lett. And we are currently working on addressing them. The report summarizing the results for the branching ratios of 156 Eu (our previous measurement) was submitted to WebPMIS.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Improving Fission Products at CARIBU: Near Field Detection (Q3/FY23 Quarterly Progress Report)

We have worked on addressing the referees’ comments and are about to resubmit the article describing the results of our mass (of the isomer and ground state) measurement of 128 Sb to Phys. Rev. Letters. We have also been working with our summer student Asha (Seaborg Institute student from Notre Dame University) on setting her up to rerun all beta detector simulations for 111 Ag. With her successful contribution of the simulation work we expect to have the simulated efficiency results by the end of the summer.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Fission Product Yields: SCALE/ORNL Perspective [Slides]

This presentation covers a few key points. First and foremost, that ORIGEN is a consumer of FPY data. Secondly, TRITON and POLARIS are assets which can be used to validate new FPY data, e.g., from existing radiochemical benchmarks and new irradiation experiments. Lastly, this presentation finds that new capabilities with covariance data should be developed, and V and V methods and analysis are also needed for the covariance data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Improving Fission Products at CARIBU: Near Field Detection (Q1/FY24 Quarterly Progress Report)

The article on “Direct Mass Measurements to Inform the Behavior for 128mSb in Nucleosynthesis Environments” by Daniel Hoff et al., recently published in Physical Review Letters. The results of the work are a combination of an extraordinary work on precision mass measurements performed with the Canadian Penning Trap at ANL (the most precise mass measurement of the ground state and the isomeric state in 128Sb performed to date), and an extensive nucleosynthesis theory calculation that include isomers performed by the theorists at LANL.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Improving Fission Products at CARIBU: Near Field Detection (Q2/FY24 Quarterly Progress Report)

We continue to make progress in the analysis of 111 Ag decay data to determine gamma-ray intensities with the aim of improving these intensities to below 1% precision. The correctness of detection efficiencies is integral to obtaining accurate and precise results. While Geant4 provides us with efficiencies for detection of a coincidence event of a beta-particle with a 96, 245, or 342 gamma-ray, as outlined in Figure 1, it is important that we validate these results with the efficiencies obtained from the experimental decay data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Property Measurements of LiF-NaF-KF Molten Salts Doped with Surrogate Fission Products

Measurements of molten salt properties including transition temperatures, phase behavior, heat capacity, density, volumetric thermal expansion, surface tension, viscosity thermal diffusivity, thermal conductivity, and vapor pressure are performed at Argonne. The properties of several fuel and coolant salts including eutectic LiF-NaF-KF (FLiNaK) have been measured. These properties are suitable for use in evaluating reactor performance during startup and early operating conditions.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Develop and Connect TRISO Failure Analysis and Uncertainty Quantification to Fission Product Release Calculation Capability

The U.S. Department of Energy’s Nuclear Energy Advanced Modeling and Simulation (NEAMS) program aims to develop predictive capabilities by applying computational methods to the analysis and design of advanced reactor and fuel cycle systems. This program has been providing engineering-scale support for the development of BISON, a high-fidelity and high-resolution fuel performance tool. Stress-based failure probability has been developed and analyzed to assess the integrity of tri-structural isotropic (TRISO) fuel particles during fuel life cycles. While simple, stress-based approaches to failure probability leveraging the Weibull statistical distribution entails a number of drawbacks when stress concentration occurs near crack tips, including finite element mesh size dependency. In this report, we use an interaction integral approach to the computation of stress intensity factors in functionally graded materials (FGM) for axisymmetric models. The inner pyrolytic carbon (IPyC) cracking induced silicon carbide (SiC) failure is one of the dominated failure modes in TRISO failure analysis. In this study, we consider a crack in the IPyC layer perpendicular to the SiC layer. The interface between these two TRISO layers is considered to be porous, which we simulate considering a transition of mechanical properties over the porous length. These aspects are considered in the computation of stress intensity factor (SIF) from a fracture mechanics approach and compared with the known stress-based failure probability approach.

42 ENGINEERING↗