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All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Keeping the Momentum and Nuclear Forensics at Los Alamos National Laboratory

LANL has 70 years of experience in nuclear forensics and supports the community through a wide variety of efforts and leveraged capabilities: Expanding the understanding of nuclear forensics, providing training on nuclear forensics methods, and developing bilateral relationships to expand our understanding of nuclear forensic science. LANL remains highly supportive of several key organizations tasked with carrying forth the Nuclear Security Summit messages: IAEA, GICNT, and INTERPOL. Analytical chemistry measurements on plutonium and uranium matrices are critical to numerous programs including safeguards accountancy verification measurements. Los Alamos National Laboratory operates capable actinide analytical chemistry and material science laboratories suitable for nuclear material and environmental forensic characterization. Los Alamos National Laboratory uses numerous means to validate and independently verify that measurement data quality objectives are met. Numerous LANL nuclear facilities support the nuclear material handling, preparation, and analysis capabilities necessary to evaluate samples containing nearly any mass of an actinide (attogram to kilogram levels).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Nuclear forensics of a non-traditional sample: Neptunium

Recent nuclear forensics cases have focused primarily on plutonium (Pu) and uranium (U) materials. By definition however, nuclear forensics can apply to any diverted nuclear material. This includes neptunium (Np), an internationally safeguarded material like Pu and U, that could offer a nuclear security concern if significant quantities were found outside of regulatory control. This case study couples scanning electron microscopy (SEM) with quantitative analysis using newly developed specialized software, to evaluate a non-traditional nuclear forensic sample of Np. Here, the results of the morphological analyses were compared with another Np sample of known pedigree, as well as other traditional actinide materials in order to determine potential processing and point-of-origin.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Women as a force multiplier for bringing nuclear forensic capabilities to the international stage

In 2009, the U.S. Department of Energy / National Nuclear Security Administration’s (DOE/NNSA) Defense Nuclear Nonproliferation (DNN) Program initiated a new nuclear forensics outreach effort under its Confidence Building Measures Program. Little did they know that the timing could not have been better. This article focuses on the early years (2009-2015) of the NNSA’s international nuclear forensics outreach, specifically the efforts and experiences of the women who helped establish this program, building it from a fledgling bilateral effort into an enduring technical capacity provider engaging with dozens of countries and multilateral organizations. At the onset of the program, nuclear forensics was an emerging priority within the U.S. Government and receiving increased focus from international organizations through high-level diplomatic efforts such as the Nuclear Security Summit and Global Initiative to Combat Nuclear Terrorism. Additionally, working-level initiatives were gaining traction through the International Atomic Energy Agency and the Nuclear Forensics International Technical Working Group. Over the next six years, a small team comprised of a uniquely large number of women NNSA federal, contract, and national laboratory staff served as key leaders engaging with the international community to strengthen global technical nuclear forensics capacity and best practices. The program continues today under the Nuclear Smuggling Detection and Deterrence Program as Investigation Support. The experiences shared here detail a unique time period when the new technical discipline of nuclear forensics was beginning to mature and gain international traction. The authors have made every effort to remember history correctly and be as inclusive as possible. A wealth of training, guidance, and exercises documentation was developed in the 2009-2015 timeframe, much of which still serves as the foundation for today’s even more extensive program and community of dedicated technical and diplomatic practitioners.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2015

Leveraging existing information for use in a National Nuclear Forensics Library (NNFL)

A National Nuclear Forensics Library (NNFL) assists a State to assess whether nuclear material encountered out of regulatory control is of domestic or international origin. And by leveraging nuclear material registries, nuclear enterprise records, and safeguards accountancy information, as well as existing domestic technical capability and subject-matter domain expertise, states can better assess the effort required for setting up an NNFL. For states who are largely recipients of nuclear and radiological materials and have no internal production capabilities may create an NNFL that relies on existing information rather than carry out advanced analyses on domestic materials.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2015

2015 LLNL Nuclear Forensics Summer Program

The Lawrence Livermore National Laboratory (LLNL) Nuclear Forensics Summer Program is designed to give graduate students an opportunity to come to LLNL for 8–10 weeks for a hands-on research experience. Students conduct research under the supervision of a staff scientist, attend a weekly lecture series, interact with other students, and present their work in poster format at the end of the program. Students also have the opportunity to meet staff scientists one-on-one, participate in LLNL facility tours (e.g., the National Ignition Facility and Center for Accelerator Mass Spectrometry) to gain a better understanding of the multidisciplinary, on going science at LLNL. Currently called the Nuclear Forensics Summer Program, this program began 15 years ago as the Actinide Sciences Summer Program. The program is run within the Glenn T. Seaborg Institute in the Physical and Life Sciences Directorate at LLNL. The goal of the Nuclear Forensics Summer Program is to facilitate the training of the next generation of nuclear scientists and engineers to solve critical national security problems in the field of nuclear forensics and have the students participate in conducting research at LLNL. We select students who are majoring in physics, chemistry, geology, mathematics, nuclear engineering, chemical engineering and environmental sciences. Students engage in research projects in the disciplines of actinide chemistry, radiochemistry, isotopic analysis, computational analysis, radiation detection, and nuclear engineering in order to strengthen the “pipeline” for future scientific disciplines critical to DHS (DNDO), NNSA.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2013

2013 LLNL Nuclear Forensics Summer Program

The Lawrence Livermore National Laboratory (LLNL) Nuclear Forensics Summer Program is designed to give both undergraduate and graduate students an opportunity to come to LLNL for 8–10 weeks for a hands-on research experience. Students conduct research under the supervision of a staff scientist, attend a weekly lecture series, interact with other students, and present their work in poster format at the end of the program. Students also have the opportunity to meet staff scientists one-on-one, participate in LLNL facility tours (e.g., the National Ignition Facility and Center for Accelerator Mass Spectrometry) to gain a better understanding of the multi-disciplinary, on going science at LLNL. Currently called the Nuclear Forensics Summer Program, this program began 13 years ago as the Actinide Sciences Summer Program. The program is run within the Glenn T. Seaborg Institute in the Physical and Life Sciences Directorate at LLNL. The goal of the Nuclear Forensics Summer Program is to facilitate the training of the next generation of nuclear scientists and engineers to solve critical national security problems in the field of nuclear forensics and have the student experience conducting research at the Lab. We select students who are majoring in physics, chemistry, geology, mathematics, nuclear engineering, chemical engineering and environmental sciences. Students engage in research projects in the disciplines of actinide chemistry, radiochemistry, isotopic analysis, computational analysis, radiation detection, and nuclear engineering in order to strengthen the “pipeline” for future scientific disciplines critical to DHS (DNDO), NNSA.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2025

Klaus Mayer's Legacy and Leadership of Nuclear Forensics and the International Technical Working Group

The Nuclear Forensics International Technical Working Group (ITWG), in an evidentiary sense, has Dr. Klaus Mayer’s fingerprints all over it. His contributions to the working group and the broader international nuclear forensics community have been profound. As Klaus retires from the European Commission’s Joint Research Centre in Karlsruhe, Germany (JRC-Karlsruhe), it is only fitting to reflect on his dedication and lasting impact on nuclear forensics—guiding its evolution from its early days to its establishment as a vital tool for competent authorities in preventing and responding to the serious threat of nuclear and other radioactive materials out of regulatory control.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2015

Analytical and Radiochemistry for Nuclear Forensics

Information about nonproliferation nuclear forensics, activities in forensics at Los Alamos National Laboratory, radio analytical work at LANL, radiochemical characterization capabilities, bulk chemical and materials analysis capabilities, and future interests in forensics interactions.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2024

Evaluating Nuclear Forensic Signatures for Advanced Reactor Deployment: A Research Priority Assessment

The development and deployment of a new generation of nuclear reactors necessitates a thorough evaluation of techniques used to characterize nuclear materials for nuclear forensic applications. Advanced fuels proposed for use in these reactors present both challenges and opportunities for the nuclear forensic field. Many efforts in pre-detonation nuclear forensics are currently focused on the analysis of uranium oxides, uranium ore concentrates, and fuel pellets since these materials have historically been found outside of regulatory control. The increasing use of TRISO particles, metal fuels, molten fuel salts, and novel ceramic fuels will require an expansion of the current nuclear forensic suite of signatures to accommodate the different physical dimensions, chemical compositions, and material properties of these advanced fuel forms. In this work, a semi-quantitative priority scoring system is introduced to identify the order in which the nuclear forensics community should pursue research and development on material signatures for advanced reactor designs. This scoring system was applied to propose the following priority ranking of six major advanced reactor categories: (1) molten salt reactor (MSR), (2) liquid metal-cooled reactor (LMR), (3) very-high-temperature reactor (VHTR), (4) fluoride-salt-cooled high-temperature reactor (FHR), (5) gas-cooled fast reactor (GFR), and (6) supercritical water-cooled reactor (SWCR).

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Microscale Isotopic Variation in Uranium Fuel Pellets with Implications for Nuclear Forensics

Until recently, the analysis and identification of nuclear fuel pellets in the context of a nuclear forensics investigation have been mainly focused on macroscopic characteristics, such as fuel pellet dimensions, uranium enrichment, and other reactor-specific features. Here, we report microscale isotopic heterogeneity observed in different fuel pellet fragments that were characterized in situ by nanoscale secondary ion mass spectrometry (NanoSIMS). The materials analyzed include fuel fragments obtained as part of the Collaborative Materials Exercise (CMX-4) organized by the Nuclear Forensics International Technical Working Group (ITWG), as well as a fuel pellet fragment from a commercial power reactor. Although the commercial fuel pellet showed a homogeneous 235 U/ 238 U ratio across the sample (within analytical error), NanoSIMS imaging of the CMX-4 fuel pellet fragments showed distinct microscale variations in the uranium isotopic composition. The average 235 U enrichments were 2.2 and 2.9% for the two samples; however, the measured 235 U/ 238 U ratios varied between 0.0081 and 0.035 (0.79–3.3 atom % 235 U) and between 0.0090 and 0.045 (0.89–4.3 atom % 235 U). The measurement of 236 U in one of the CMX-4 samples suggested the use of at least three uranium oxide powders of different isotopic compositions (“source terms”) in the production of the pellets. These variations were not detected using the conventional bulk, macroscopic techniques applied to these materials. Furthermore, our study highlights the importance of characterizing samples on the microscale for heterogeneities that would otherwise be overlooked and demonstrates the potential use of NanoSIMS in guiding further nuclear forensic analysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Updated uranium reference material 231 Pa/ 235 U consensus model ages for nuclear forensics

Radiochronometry provides the model age of nuclear materials, which is useful for understanding the production history of materials found outside of regulatory control. Certified reference materials (CRMs) are important for radiochronometry to increase confidence in measurement quality; however, the absence of 231 Pa/ 235 U CRMs necessitates that nuclear forensic laboratories measure the 231 Pa/ 235 U model ages of preexisting uranium reference materials. Here, in this work, new consensus 231 Pa/ 235 U model ages are reported from three nuclear forensic laboratories for three reference materials using current analytical methods. These updated consensus values can be used for quality control of 231 Pa/ 235 U model age measurements.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

National nuclear forensics libraries: a case study on benefits and possibilities for identification of sealed radioactive sources

A National Nuclear Forensic Library (NNFL) is a useful nuclear forensics tool which consists of information and subject matter expertise on radioactive and nuclear (RN) materials produced, used or stored within a State. If RN material is found out of regulatory control the NNFL can be used as part of a nuclear forensics investigation to help identify whether or not the material is consistent with a country’s national holdings. In previous work, a number of signatures which can be useful to identify sealed sources of 241 Am were investigated. To validate the measurement results, an official query concerning information about two of the previously investigated 241 Am sources was sent to the United States Department of State, the international point-of-contact (POC) for the U.S. NNFL. The aim of this work is to show how data obtained in a characterization of a radioactive source can be used in conjunction with an NNFL to investigate the history of a source out of regulatory control.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2016

Nuclear Forensics for Irradiated Materials using Kernel Regression Models

The ultimate purpose of nuclear forensics is to locate the origin of nuclear and other radioactive materials out of regulatory control used in nuclear security events such as classical forensics. For this purpose, some specific characteristics of interdicted materials (referred to as 'signatures') should be defined to compare the known sample database. In some cases, involved with irradiated material, the signatures could be specific amount of fission product inventory depending on reactor operational histories such as reactor type, initial enrichment, burn up rate of nuclear fuel and cooling period after irradiation in the reactor. In order to make inference model for irradiated material for nuclear forensics, we suggested 3 ways as follows; (i) analyzing ORIGEN produced nuclear substances for the fission product inventory, (ii) classifying the range of reactor type, (iii) predicting the operational history from the fission product inventory. In terms of nuclear substance analysis, the construction of spent fuel database has been internationally carried out since ITWG (Nuclear Smuggling International Technical Working Group) was established in 1995. However, enough sample data cannot be obtained in Korea to determine reactor type and operational histories because analyzing nuclear substances have been limited due to the international regulation. Thus, this study does not mention how to obtain mass or ratios of nuclides for the spent fuel. We just have generated simulation sample data as a fission product inventory using ORIGEN to construct spent fuel database. When unidentified radioactive materials are discovered, it is assumed that mass or ratios of the nuclides are analyzed by certain methods which are available in Korea as well as other countries. Then, a reactor type is determined, and finally, regression model can locate the origin or source of the radioactive materials by inferring operational histories using the fission product inventory. There are some studies on the classification of reactor type using statistical methods. As a part of predicting the operational history, this paper focuses on the development of spent fuel inference algorithm for nuclear forensics to estimate reactor operational histories that reflect characteristics of a reactor from the fission product inventory. The spent fuel inference algorithm for nuclear forensics has been developed on the basis of Kernel Regression (KR) which can conditionally generate the estimated output data by giving weight depending on geometric distance between sample data and input data. Also the KR which comprises Auto-Associative KR and Inferential KR have some benefits that can estimate only using data without assumption for specific physical model and re-learning process. Auto-associative KR (AAKR) was used to sort out outliers of input data and Inferential KR (IKR) was carried out to predict the operational histories for spent fuel. All of regression algorithms were performed in R programming tool. From the validation of both AAKR and IKR, it is expected that kernel regression has enough accuracy to be applied to nuclear forensics for spent fuel. Once the nuclear substance is measured to fill the fission product inventory with a certain reactor type, this kernel regression algorithm would predict the operational histories of spent fuel with high accuracy. Finally, this information is expected to be useful to find the origin of irradiated materials. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Leveraging Machine Learning Capabilities for the Characterization of Irradiated Uranium: A Case Study of Analysis Methods for Nuclear Safeguards and Nuclear Forensics

Nondestructively determining the initial enrichment of irradiated uranium is a complex and laborious multivariable problem due to the presence of fission products. This work demonstrates the capabilities of machine learning to analyze gamma-ray spectral data to determine initial enrichment without knowledge of the decay time of the sample. The approach developed is agnostic to the particular scenario and is applicable to a wide variety of applications in nuclear forensics and nuclear safeguards. We irradiated 5 mg uranium standard reference materials at discrete enrichment values ranging from 0.02% to 97% 235 U (weight percent) in UT Austin’s Nuclear Engineering Teaching Laboratory TRIGA Mark II 1.1 MW research reactor, allowed each to decay for 8 hours, and then measured each sample via gamma-ray spectrometry for 50 hours post-irradiation yielding 1,400 individual gamma-ray spectra discretized into 8,192 energy bins. We then trained decision trees models to analyze individual gamma-ray spectra and estimate the associated initial enrichment without knowledge of the time since end of irradiation. We evaluated the performance of the models with a reserved test set not used for training or calibrating the model. A decision tree model constructed with this procedure achieved a mean absolute error in initial enrichment determination of 2.3% (weight percent 235 U). Next, we implemented a principal component analysis pre-processing routine of the gamma-ray spectrometry data to reduce the dimensionality of the dataset from 8,192 channels in the spectrum to 10 principal components while retaining over 99% of the inherent variance in the data. Decision tree models constructed with these data demonstrated decreased mean absolute error in enrichment determination, reduced computational time, and decreased complexity. A single decision tree model constructed with this procedure achieved a mean absolute error in initial enrichment determination of 0.05% (weight percent 235 U). Furthermore, we analyzed these models with learning curves to ensure that overfitting did not occur. The capabilities provided by these models can be naturally extended to other application-focused measurements in the fields of nuclear safeguards, nuclear forensics, and nuclear non-proliferation.

Drescher, Adam↗
DOE OSTI2017

Improved sample utilization in thermal ionization mass spectrometry isotope ratio measurements: refined development of porous ion emitters for nuclear forensic applications

The precise and accurate determination of isotopic composition in nuclear forensic samples is vital for assessing origin, intended use and process history. Thermal ionization mass spectrometry (TIMS) is widely accepted as the gold standard for high performance isotopic measurements and has long served as the workhorse in the isotopic ratio determination of nuclear materials. Nuclear forensic and safeguard specialists have relied heavily on such methods for both routine and atypical e orts. Despite widespread use, TIMS methods for the assay of actinide systems continue to be hindered by poor ionization e ciency, often less than tenths of a percent; the majority of a sample is not measured. This represents a growing challenge in addressing nextgeneration nuclear detection needs by limiting the ability to analyze ultratrace quantities of high priority elements that could potentially provide critical nuclear forensic signatures. Porous ion emitter (PIE) thermal ion sources were developed in response to the growing need for new TIMS ion source strategies for improved ionization e ciency, PIEs have proven to be simple to implement, straightforward approach to boosting ion yield. This work serves to expand the use of PIE techniques for the analysis of trace quantities of plutonium and americium. PIEs exhibited superior plutonium and americium ion yields when compared to direct lament loading and the resin bead technique, one of the most e cient methods for actinide analysis, at similar mass loading levels. Initial attempts at altering PIE composition for the analysis of plutonium proved to enhance sample utilization even further. Preliminary investigations of the instrumental fractionation behavior of plutonium and uranium analyzed via PIE methods were conducted. Data collected during these initial trial indicate that PIEs fractionate in a consistent, reproducible manner; a necessity for high precision isotope ratio measurements. Ultimately, PIEs methods were applied for the age determination of various uranium isotopic standards. PIEs did not exhibit signi cant advantages for the determination of model ages when compared to traditional laments; however, this trial was able to provide valuable insight for guiding future investigations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Nuclear Forensics in Support of National Response Plans [Slides]

Become familiar with nuclear forensics methodologies in support of nuclear security investigations and how Los Alamos National Laboratory supports the development of sustainable global nuclear forensics capacities.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2015

Nuclear forensic analysis of uranium oxide powders interdicted in Victoria, Australia

Nuclear forensic analysis was conducted on two uranium samples confiscated during a police investigation in Victoria, Australia. The first sample, designated NSR-F-270409-1, was a depleted uranium powder of moderate purity (~1000 μg/g total elemental impurities). The chemical form of the uranium was a compound similar to K 2 (UO 2 ) 3 O 4 ·4H 2 O. While aliquoting NSR-F-270409-1 for analysis, the body and head of a Tineid moth was discovered in the sample. The second sample, designated NSR-F-270409-2, was also a depleted uranium powder. It was of reasonably high purity (~380 μg/g total elemental impurities). The chemical form of the uranium was primarily UO 3 ·2H 2 O, with minor phases of U 3 O 8 and UO 2 . While aliquoting NSR-F-270409-2 for analysis, a metal staple of unknown origin was discovered in the sample. The presence of 236 U and 232 U in both samples indicates that the uranium feed stocks for these samples experienced a neutron flux at some point in their history. The reactor burn-up calculated from the isotopic composition of the uranium is consistent with that of spent fuel from natural uranium (NU) fueled Pu production. These nuclear forensic conclusions allow us to categorically exclude Australia as the origin of the material and greatly reduce the number of candidate sources.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗