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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Radioisotope production using lasers: From basic science to applications

The discovery of chirped pulse amplification has led to great improvements in laser technology, enabling energetic laser beams to be compressed to pulse durations of tens of femtoseconds and focused to a few micrometers. Protons with energies of tens of MeV can be accelerated using, for instance, target normal sheath acceleration and focused on secondary targets. Under such conditions, nuclear reactions can occur, with the production of radioisotopes suitable for medical application. The use of high-repetition lasers to produce such isotopes is competitive with conventional methods mostly based on accelerators. In this paper, we study the production of 67Cu, 63Zn, 18F, and 11C, which are currently used in positron emission tomography and other applications. At the same time, we study the reactions 10B(p,α)7Be and 70Zn(p,4n)67Ga to put further constraints on the proton distributions at different angles, as well as the reaction 11B(p,α)8Be relevant for energy production. The experiment was performed at the 1 PW laser facility at Vega III in Salamanca, Spain. Angular distributions of radioisotopes in the forward (with respect to the laser direction) and backward directions were measured using a high purity germanium detector. Our results are in reasonable agreement with numerical estimates obtained following the approach of Kimura and Bonasera [Nucl. Instrum. Methods Phys. Res., Sect. A 637, 164–170 (2011)].

11C↗
DOE OSTI2022

Typical Neutron Emission Spectra for Multi-Mission Radioisotope Thermoelectric Generator Fuel

The Dragonfly rotorcraft currently being designed by the Johns Hopkins Applied Physics Laboratory (APL) is a mission destined to explore, via autonomous flight, the Saturnian moon of Titan and currently scheduled to launch in 2027. This largest moon of Saturn contains a thick, dense atmosphere, that when coupled with the remote distance to the Sun, requires the use of a radioisotope power system (RPS). The multi-mission radioisotope thermoelectric generator (MMRTG) fueled at Idaho National Laboratory is currently the only flight-certified RPS still in production within the Department of Energy complex, thus, an MMRTG was chosen for the Dragonfly mission.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2025

A virtual Frisch-grid geometry-based CZT gamma detector for in-field radioisotope identification

Here, we present a Virtual Frisch-Grid geometry-based CZT gamma detector developed for identifying different radioisotopes over an energy range from a few keV up to 2 MeV, and useful for efficient characterization of CZT crystals. The detector is built with a 3 x 3 matrix of CZT crystals, each measuring approximately 6 mm x 6 mm x 15 mm. The charge generated within the sensor’s active volume is read out via an anode connected directly to the AVG3_Dev integrated circuit. A current signal induced by charge drift is collected on side pads of the crystals, enabling reconstruction of a 3D interaction position. This paper discusses the design, development, and performance of the standalone, mobile detector system, which integrates the AVG3_Dev readout IC developed at Brookhaven National Laboratory, a high-speed FPGA-based with per-channel digital signal processing, and embedded system capabilities. The device is compact, battery-powered, and supports wireless data streaming, making it suitable for field operations for radioisotope identification.

47 OTHER INSTRUMENTATION↗
DOE OSTI2026

Unsupervised domain adaptation for radioisotope identification in gamma spectroscopy

Training machine learning models for radioisotope identification using gamma spectroscopy remains an elusive challenge for many practical applications, largely stemming from the difficulty of acquiring and labeling large, diverse experimental datasets. Simulations can mitigate this challenge, but the accuracy of models trained on simulated data can deteriorate substantially when deployed to an out-of-distribution operational environment. In this study, we demonstrate that unsupervised domain adaptation (UDA) can improve the ability of a model trained on synthetic data to generalize to a new testing domain, provided unlabeled data from the target domain are available. Conventional supervised techniques are unable to utilize this data because the absence of isotope labels precludes defining a supervised classification loss. Instead, we first pretrain a spectral classifier using labeled synthetic data and subsequently leverage unlabeled target data to align the learned feature representations between the source and target domains. We compare a range of different UDA techniques, finding that minimizing the maximum mean discrepancy (MMD) between source and target feature vectors yields the most consistent improvement to testing scores. For instance, using a custom transformer-based neural network, we achieved a testing accuracy of $0.904 \pm 0.022$ on an experimental LaBr test set after performing unsupervised feature alignment via MMD minimization, compared to $0.754 \pm 0.014$ before alignment. Overall, our results highlight the potential of using UDA to adapt a radioisotope classifier trained on synthetic data for real-world deployment.

Lalor, Peter W.↗
DOE OSTI2021

Assessment of alternative radionuclides for use in a radioisotope thermoelectric generator

238 Pu is the current fuel source for MMRTGs. This is due to favorable properties, such as high decay heat and low gamma emissions. 238 Pu supplies are dwindling rapidly, necessitating the review of potential replacement isotopes for deep space missions. This work considers nine potential replacements, Ac-227, Am-241, Cf-252, Cm-244, Cs-137, Po-210, Sr-90, Th-228, and Th-170. We have assessed performance of alternatives to 238 Pu by modeling the specific decay-heat and gamma spectra of several potential radioisotopes in SCALE-ORIGEN, and comparing these with 238 Pu. An analysis of heat output, heat stability, safety, availability and required mass, baselined against 238 Pu demonstrates that of those radioisotopes studied, 241 Am has properties that make it most conducive for 238 Pu replacement.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Radioisotope production at the Spallation Neutron Source: Design concept of isotope production target

Upon completion of the Second Target Station (STS) Project in the mid 2030s, the Spallation Neutron Source accelerator at Oak Ridge National Laboratory will deliver a 2.7 MW proton beam to the neutron production targets. In the post-STS phase, the accelerator will have a reserve beam power capacity of at least 100 kW beyond what the two neutron production targets will receive, which could potentially be ramped up to 300 kW. In this paper, a design concept for a radioisotope production target that could utilize 250 kW of the reserve beam power capacity is presented. The target consists of thorium discs encapsulated in 316L austenitic steel shells that are cooled by water. The estimated post-irradiation activity of Ac-225 and Ra-225, critical medical radioisotopes used in targeted alpha therapy cancer treatment, is calculated at the end of bombardment after a 14 day long irradiation time. Thermal and structural analyses are performed on the basis of calculated nuclear heating data. The technical feasibility of a high-power target under a 250-kW beam load with an extremely low duty factor of $3.5\cdot 10^{-6}$ is presented from thermal, structural and fatigue lifetime perspectives.

Lee, Yong Joong [ORNL] (ORCID:0000000298381723)↗
DOE OSTI2024

Radioisotope Analysis of Wastewater from Livermore Site Retention Tanks by Gel Laboratory Gross Alpha, Gross Beta and Tritium Sampling Method

Lawrence Livermore National Laboratory discharged approximately 4.4% of the City of Livermore’s total wastewater in 2022 (LLNL’s Annual Site Environmental Report, Chapter 5, 2022). This volume includes wastewater from Sandia National Laboratories (SNL) and some process wastewater from Site 300. Due to the high volume and constituents of the discharge, LLNL works alongside the City of Livermore under permit #1250, requiring wastewater generated to be monitored and sampled in accordance with permit limits. Process wastewater, from buildings with the highest risk to sewer, is collected by wastewater retention tanks throughout the Livermore Site and sampled prior to discharge. Domestic wastewater directly discharges to sanitary sewer. To maintain permit requirements and ensure proper wastewater discharge practices, an internal wastewater audit was conducted during the summer of 2023. Current wastewater practices, regulatory knowledge and risk management across various Livermore Site buildings were evaluated. Workspaces connected to a wastewater retention tank and sanitary sewer drains were major focus areas. Data collected from walk-throughs prompted further evaluation as many practices were reported to be done based on historical usage. A table of concerns was created to showcase reasons for auditing and proceeding action. An analysis of current and historical retention tank usage throughout LLNL Livermore Site buildings with radioisotope results over a 5-year period from 2019 to 2024, was done to assess building trends and any significant changes throughout the 5-year period. Analytes evaluated were Gross Alpha, Gross Beta and Tritium (GABT) of eleven buildings at the Livermore Site, posing the highest risk to sanitary sewer for radioisotopes.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

High efficiency continuous-flow production of radioisotopes

Methods and systems are provided for continuous-flow production of radioisotopes with high specific activity. Radioisotopes with high specific activity produced according to the methods described are also provided. The methods can include causing a liquid capture matrix to contact a target containing a target nuclide; irradiating the target with radiation, ionizing radiation, particles, or a combination thereof to produce the radionuclides that are ejected from the target and into the capture matrix; and causing the liquid capture matrix containing the radionuclides to flow from the target to recover the capture matrix containing the radionuclides with high specific activity. The methods are suitable for the production of a variety of radionuclides. For example, in some aspects the target nuclide is 237Np, and the radionuclide is 238Np that decays to produce 238Pu. In other aspects, the target nuclide is 98Mo, and the radionuclide is Mo that decays to produce 99mTc.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2021

Extractants and extractant compositions for radioisotope and metal recovery

Disclosed herein are embodiments of an extractant that can be used for chromatographic isolation of radioisotopes and/or metal species. The extractant can be combined with a support medium to provide an extractant composition that selectively and efficiently binds particular radioisotopes and/or metal species. Also disclosed herein are embodiments of a method for using the disclosed extractant embodiments, as well as embodiments of a method for making the extractant and extractant composition.

Stein, Benjamin W.↗
DOE OSTI2024

Production of High Specific Activity 155 Tb, 161 Tb and 203 Pb for Research and Clinical Applications: Effective Target Design, Target Material Recycling and Radioisotope Separation (Final Technical Report)

The overall objectives of this project were (1) to develop methods for the production and separation of a diagnostic and therapeutic or “theranostic” pair of radioisotopes, terbium-155 ( 155 Tb) and terbium-161 ( 161 Tb) and (2) to train graduate students and postdoctoral fellows in technologies and methods used in radionuclide production. Radionuclides can be incorporated into drugs called radiopharmaceuticals that target a specific disease (e.g., cancer). The need for theranostic radionuclides is escalating with the clinical translation of radiopharmaceuticals due to their implementation in personalized medicine, which has demonstrated enhanced patient treatments. High purity and high specific activity radionuclides are critical for theranostic agent development, for example to maintain diagnostic image quality, to minimize radiation dose to the patient, and to increase uptake in the targeted tissue (e.g., tumor), especially in the case of receptor- and antigen-targeted agents. The 155 Tb (diagnostic) and 161 Tb (therapeutic) radioisotopes that were generated through this project are a theranostic pair with demonstrated potential for the development and translation into individualized, targeted, and dosimetry-driven radiotherapies. However, the development of such radiotherapies has been hindered by the lack of a routine and reliable supply of these isotopes in the United States. Methods for the production, separation, and supply of 155 Tb and 161 Tb were investigated and developed in this project. Further, the strong emphasis throughout the project on the training of graduate students and postdoctoral fellows has helped to ensure and enhance the nuclear science workforce through the training of the next generation of highly qualified scientists in nuclear and radiochemistry. This grant also continued a collaboration between scientists at the University of Washington (UW), the University of Missouri (MU) and Brookhaven National Laboratory (BNL). All three institutions were involved in the project, but to different degrees on the various tasks through which the overall objectives were met.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2021

Thermal analyses of high-power advanced thermoacoustic radioisotope power system for future space exploration missions

This paper presents the results of 3-D thermal analyses of the heat source assembly of a 440 We advanced radioisotope power system (RPS) for future space exploration missions. This high thermal efficiency RPS employs a heat source assembly of eight Step 2 General Purpose Heat Source (GPHS) modules and four Thermoacoustic Power Converter (TAPC) units. Each unit is thermally coupled to two GPHS modules. Here, the analyses investigated the temperatures of the Iridium (Ir) alloy cladding of the 238 PuO 2 fuel pellets and the surface of the Fine Weave Pierced Fabric (FWPF) aeroshell in the GPHS modules to ensure reliable operation and safety in case of an unlikely reentry. Conductive coupling of the GPHS modules to the heater heads of the TAPC units produces relatively uniform axial and azimuthal distributions of heat flux and temperature. However, for this case the temperature of the Ir alloy cladding is lower than the desired values of 1173 K to maintain sufficient ductility. Adding a 5 mm wide He filled gap and decreasing the thickness of the graphite sleeve to 10 mm increased Ir cladding temperature to 1197–1174 K, which are in the desired range. The maximum surface temperatures of the FWPF graphite aeroshell of 1022–1131 K is well below the NASA specified limit of 1373 K. In addition, the total mass of the heat source assembly decreased by 19.6 kg, ~43% saving compared to original design.

42 ENGINEERING↗
DOE OSTI2021

High-Current Light-Ion Cyclotron for Applications in Nuclear Security and Radioisotope Production

In this article, we propose the conceptual design, with supporting beam dynamics results, of a normal conducting, separated-sector cyclotron with a strong-focusing field gradient designed to accelerate light ions with a charge-to-mass ratio of 1/2 up to 15–20 MeV/u. The design can support a host of applications for therapy, radiobiology, material science, and instrumentation development. The light-ion species, which can include a mixed ion beam, can be dynamically chosen to provide a range of characteristic signals appropriate for specific material identification such as special nuclear materials. A conservative baseline concept is presented which has been optimized for radioisotope production of alpha emitters and theranostic radiopharmaceuticals. The modular design is also demonstrated to be scalable in gross physical parameters by a factor of 2–3, thereby reducing the size, weight, and power requirements (SWaP) and enabling near-term security applications.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2022

Light Weight Radioisotope Heater Unit User’s Guide

This user's guide provides an overview of Light Weight Radioisotope Heater Units (LWRHU), including aspects of its physical design and performance under normal operations. This guide also identifies the planning and execution involved in launching a nuclear payload. Physical characteristics, interfaces, and environmental characteristics of the LWRHU are discussed in detail. Information relating to project management interfaces and effort.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2020

Magnetics Testing on Radioisotope Power Systems at the Idaho National Laboratory

National Aeronautics and Space Administration (NASA) uses Radioisotope Power Systems (RPS) to power deep-space and planetary explorations such as Cassini-Huygens, Galileo, New Horizons, Mars Science Laboratory—Curiosity, and most recently Mars 2020--Perseverance. The Space Nuclear Power and Isotope Technologies (SNPIT) division, at Idaho National Laboratory (INL), fuels, tests, and delivers the RPS to ensure it can provide the electrical power needed to complete mission objectives. Some space crafts have instrumentation specifically designed to study the subject’s magnetic field or may have instruments that can be affected by magnetic fields produced by the RPS. Analyzing and measuring the RPS’s magnetic fields ensures the required thresholds are not exceeded and accurate data can be collected for the mission. Magnetics testing provides numerical values of the RPS’s magnetic field. During Magnetics testing at INL, the RPS is placed on a resistive load to simulate actual spacecraft load characteristics (voltage and current). During this simulation, magnetometers are used to measure the magnetic field of the RPS. Raw data is collected and then analyzed to ensure the field created by the RPS is below NASA thresholds or that the magnitude of the field is accounted for to ensure mission success.

42 ENGINEERING↗
DOE OSTI2022

Overview of Light Weight Radioisotope Heater Unit (LWRHU) User’s Guide

Idaho National Laboratory (INL) has recently compiled a user’s guide for the Light Weight Radioisotope Heater Unit (LWRHU). This guide gives an overview of the LWRHU to potential users. Information and data on mass properties, dimensions, thermal loads, and interfaces are discussed.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2022

Overview of Light Weight Radioisotope Heating Unit (LWRHU) User’s Guide

Idaho National Laboratory (INL) has recently compiled a user’s guide for the LightWeight Radioisotope Heating Unit (LWRHU). This guide gives an overview of the LWRHU to potential users. Information and data on mass properties, dimensions, thermal loads, and interfaces are discussed.

42 ENGINEERING↗
DOE OSTI2024

Production of Medically Desirable Radioisotopes in the EIRENE Molten Salt Reactor

Radioisotopes play a vital role in nuclear medicine, enabling the performance of diagnostic procedures such as Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT), in addition to innovative targeted therapies for selectively delivering cytotoxic radiation doses to tumor cells while minimizing damage to healthy tissue [1]. Beta emitting radionuclides such as 90Y and 131I find wide use in radio-immunotherapy, with the radiopharmaceuticals 90Y-ibritumomab tiuxetan (Zevalin®) and 131I-tositumomab (Bexxar®) having received FDA approval for treatment of non-Hodgkin’s lymphoma through targeting the CD20 surface receptor, which is commonly expressed in many B cell non-Hodgkin’s lymphoma subtypes [2, 3]. 90Y has also been successfully applied for treatment of brain tumors [4, 5] and liver cancer [6]. The favorable chelation chemistry of 90Y enables its use with a variety of ligands for the development of radiopharmaceuticals suitable for targeting different carcinoma types [1].

42 - ENGINEERING↗