Draft INFL Guideline on SIMS

Secondary Ion Mass Spectrometry (SIMS) is used for elemental and isotopic analysis of solid samples. The greatest strength of SIMS is the ability to analyze very small areas (as small as 50 nm using the CAMECA NanoSIMS, for example) and to generate high-spatial resolution maps of the distribution of elements and isotopes within the sample. The measurement of the isotopic composition of sample is usually straightforward, only requiring the analysis of the sample and that of an isotopic reference material for determination of the mass bias of the instrument. Quantification of elements, however, involves the analysis of matrix matched standards for the determination of the relative sensitivity factor (a function of both the element to be analyzed and the matrix). SIMS is commonly used in nuclear forensics for exploring the heterogeneity of the material on fine spatial scale

Determination of Optimum Conditions for Distinguishing the Pulse Height Distributions of Atomic and Polyatomic Ions

This work explored the use of pulse height distributions (PHD) from multiplier-type detectors as a means of detecting and eliminating the effects of polyatomic interferences in secondary ion mass spectrometry (SIMS). We explored the behavior of PHD for {sup 235}U{sup +}, {sup 208}Pb{sup 27}Al{sup +} and {sup 207}Pb{sup 28}Si{sup +}, all with a nominal mass-to-charge ratio of 235. In every case, the distribution for the atomic ion ({sup 235}U{sup +}) was clearly shifted relative to the distributions for {sup 208}Pb{sup 27}Al{sup +} and {sup 207}Pb{sup 28}Si{sup +}. When the first surface of the detector is metallic in character, the polyatomic ions are shifted to larger pulse heights relative to the atomic ion. When the first surface of the detector is oxide in character, the atomic ion is shifted to larger pulse heights relative to the polyatomic ions. The relative positioning appear to be stable for a given detector over time at the same secondary ion impact energy. Consequently, it appears to be feasible to use PHD data to detect interfering polyatomic ions and eliminate their deleterious effects using peak deconvolution techniques. Consequently, the updated Ultrafast RAE detector will be designed to make the pulse height information available to the data acquisition system

Characterization of Nuclear Fuel using Multivariate Statistical Analysis

Various combinations of reactor type and fuel composition have been characterized using principle components analysis (PCA) of the concentrations of 9 U and Pu isotopes in the 10 fuel as a function of burnup. The use of PCA allows the reduction of the 9-dimensional data (isotopic concentrations) into a 3-dimensional approximation, giving a visual representation of the changes in nuclear fuel composition with burnup. Real-world variation in the concentrations of {sup 234}U and {sup 236}U in the fresh (unirradiated) fuel was accounted for. The effects of reprocessing were also simulated. The results suggest that, 15 even after reprocessing, Pu isotopes can be used to determine both the type of reactor and the initial fuel composition with good discrimination. Finally, partial least squares discriminant analysis (PSLDA) was investigated as a substitute for PCA. Our results suggest that PLSDA is a better tool for this application where separation between known classes is most important

U.S. and Russian Collaboration in the Area of Nuclear Forensics

Nuclear forensics has become increasingly important in the fight against illicit trafficking in nuclear and other radioactive materials. The illicit trafficking of nuclear materials is, of course, an international problem; nuclear materials may be mined and milled in one country, manufactured in a second country, diverted at a third location, and detected at a fourth. There have been a number of articles in public policy journals in the past year that call for greater interaction between the U. S. and the rest of the world on the topic of nuclear forensics. Some believe that such international cooperation would help provide a more certain capability to identify the source of the nuclear material used in a terrorist event. An improved international nuclear forensics capability would also be important as part of the IAEA verification toolkit, particularly linked to increased access provided by the additional protocol. A recent study has found that, although international progress has been made in securing weapons-usable HEU and Pu, the effort is still insufficient. They found that nuclear material, located in 40 countries, could be obtained by terrorists and criminals and used for a crude nuclear weapon. Through 2006, the IAEA Illicit Trafficking Database had recorded a total of 607 confirmed events involving illegal possession, theft, or loss of nuclear and other radioactive materials. Although it is difficult to predict the future course of such illicit trafficking, increasingly such activities are viewed as significant threats that merit the development of special capabilities. As early as April, 1996, nuclear forensics was recognized at the G-8 Summit in Moscow as an important element of an illicit nuclear trafficking program. Given international events over the past several years, the value and need for nuclear forensics seems greater than ever. Determining how and where legitimate control of nuclear material was lost and tracing the route of the material from diversion through interdiction are important goals for nuclear forensics and attribution. It is equally important to determine whether additional devices or materials that pose a threat to public safety are also available. Finding the answer to these questions depends on determining the source of the material and its method of production. Nuclear forensics analysis and interpretation provide essential insights into methods of production and sources of illicit radioactive materials. However, they are most powerful when combined with other sources of information, including intelligence and traditional detective work. The certainty of detection and punishment for those who remove nuclear materials from legitimate control provides the ultimate deterrent for such diversion and, ultimately, for the intended goal of such diversion, including nuclear terrorism or proliferation. Consequently, nuclear forensics is an integral part of 'nuclear deterrence' in the 21st century. Nuclear forensics will always be limited by the diagnostic information inherent in the interdicted material. Important markers for traditional forensics (fingerprints, stray material, etc.) can be eliminated or obscured, but many nuclear materials have inherent isotopic or chemical characteristics that serve as unequivocal markers of specific sources, production processes, or transit routes. The information needed for nuclear forensics goes beyond that collected for most commercial and international verification activities. Fortunately, the international nuclear engineering enterprise has a restricted number of conspicuous process steps that makes the interpretation process easier. Ultimately, though, it will always be difficult to distinguish between materials that reflect similar source or production histories, but are derived from disparate sites. Due to the significant capital costs of the equipment and the specialized expertise of the personnel, work in the field of nuclear forensics has been restricted so far to a handful of national and international laboratories. There are a limited number of specialists who have experience working with interdicted nuclear materials and affiliated evidence. Therefore, a knowledge management system that utilizes information resources relevant to nuclear forensic and attribution signatures, processes, origins, and pathways, allowing subject matter experts to access the right information in order to interpret forensics data and draw appropriate conclusions, is essential. In order to determine the origin, point of diversion of the nuclear material, and those responsible for the unauthorized transfer, close relationships are required between governments who maintain inventories and data of fissile or other radioactive materials. Numerous databases exist in many countries and organizations that could be valuable for the future development and application of nuclear forensics

Nuclear Forensics and Attribution for Improved Energy Security: The Use of Taggants in Nuclear Fuel

The Global Nuclear Energy Partnership (GNEP), recently announced by DOE Secretary Bodman, poses significant new challenges with regard to securing, safeguarding, monitoring and tracking nuclear materials. In order to reduce the risk of nuclear proliferation, new technologies must be developed to reduce the risk that nuclear material can be diverted from its intended use. Regardless of the specific nature of the fuel cycle, nuclear forensics and attribution will play key roles to ensure the effectiveness of nonproliferation controls and to deter the likelihood of illicit activities. As the leader of the DHS nuclear and radiological pre-detonation attribution program, LLNL is uniquely positioned to play a national leadership role in this effort. Ensuring that individuals or organizations engaged in illicit trafficking are rapidly identified and apprehended following theft or diversion of nuclear material provides a strong deterrent against unlawful activities. Key to establishing this deterrent is developing the ability to rapidly and accurately determine the identity, source and prior use history of any interdicted nuclear material. Taggants offer one potentially effective means for positively identifying lost or stolen nuclear fuels. Taggants are materials that can be encoded with a unique signature and introduced into nuclear fuel during fuel fabrication. During a nuclear forensics investigation, the taggant signature can be recovered and the nuclear material identified through comparison with information stored in an appropriate database. Unlike serial numbers or barcodes, microtaggants can provide positive identification with only partial recovery, providing extreme resistance to any attempt to delete or alter them

Action Sheet 36 Final Report

Pursuant to the Arrangement between the European Commission DG Joint Research Centre (EC-JRC) and the Department of Energy (DOE) to continue cooperation on research, development, testing, and evaluation of technology, equipment, and procedures in order to improve nuclear material control, accountancy, verification, physical protection, and advanced containment and surveillance technologies for international safeguards, dated 1 September 2008, the IRMM and LLNL established cooperation in a program on the Study of Chemical Changes in Uranium Oxyfluoride Particles under IRMM-LLNL Action Sheet 36. The work under this action sheet had 2 objectives: (1) Achieve a better understanding of the loss of fluorine in UO{sub 2}F{sub 2} particles after exposure to certain environmental conditions; and (2) Provide feedback to the EC-JRC on sample reproducibility and characteristics

Action Sheet 36 Final Report

Pursuant to the Arrangement between the European Commission DG Joint Research Centre (EC-JRC) and the Department of Energy (DOE) to continue cooperation on research, development, testing, and evaluation of technology, equipment, and procedures in order to improve nuclear material control, accountancy, verification, physical protection, and advanced containment and surveillance technologies for international safeguards, dated 1 September 2008, the IRMM and LLNL established cooperation in a program on the Study of Chemical Changes in Uranium Oxyfluoride Particles under IRMM-LLNL Action Sheet 36. The work under this action sheet had 2 objectives: (1) Achieve a better understanding of the loss of fluorine in UO{sub 2}F{sub 2} particles after exposure to certain environmental conditions; and (2) Provide feedback to the EC-JRC on sample reproducibility and characteristics