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Nuclear Resonance Fluorescence Measurements On 237np For Security And Safeguards Applications
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Book Synopsis Nuclear Resonance Fluorescence Measurements on 237Np for Security and Safeguards Applications by : Ryan Matthew Yee
Download or read book Nuclear Resonance Fluorescence Measurements on 237Np for Security and Safeguards Applications written by Ryan Matthew Yee and published by . This book was released on 2009 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nuclear Resonance Fluorescence for Safeguards Applications by :
Download or read book Nuclear Resonance Fluorescence for Safeguards Applications written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of [gamma] rays with specific energies that are characteristic of the emitting isotope. The promise of NRF as a non-destructive analysis technique (NDA) in safeguards applications lies in its potential to directly quantify a specific isotope in an assay target without the need for unfolding the combined responses of several fissile isotopes as often required by other NDA methods. The use of NRF for detection of sensitive nuclear materials and other contraband has been researched in the past. In the safeguards applications considered here one has to go beyond mere detection and precisely quantify the isotopic content, a challenge that is discussed throughout this report. Basic NRF measurement methods, instrumentation, and the analytical calculation of NRF signal strengths are described in Section 2. Well understood modeling and simulation tools are needed for assessing the potential of NRF for safeguards and for designing measurement systems. All our simulations were performed with the radiation transport code MCNPX, a code that is widely used in the safeguards community. Our initial studies showed that MCNPX grossly underestimated the elastically scattered background at backwards angles due to an incorrect treatment of Rayleigh scattering. While new, corrected calculations based on ENDF form factors showed much better agreement with experimental data for the elastic scattering of photons on an uranium target, the elastic backscatter is still not rigorously treated. Photonuclear scattering processes (nuclear Thomson, Delbruck and Giant Dipole Resonance scattering), which are expected to play an important role at higher energies, are not yet included. These missing elastic scattering contributions were studied and their importance evaluated evaluated against data found in the literature as discussed in Section 3. A transmission experiment was performed in September 2009 to test and demonstrate the applicability of the method to the quantitative measurement of an isotope of interest embedded in a thick target. The experiment, data analysis, and results are described in Section 4. The broad goal of our NRF studies is to assess the potential of the technique in safeguards applications. Three examples are analyzed in Section 5: the isotopic assay of spent nuclear fuel (SNF), the measurement of 235U enrichment in UF6 cylinders, and the determination of 239Pu in mixed oxide (MOX) fuel. The study of NRF for the assay of SNF assemblies was supported by the Next Generation Safeguards Initiative (NGSI) of the U.S. Department of Energy as part of a large multi-lab/university effort to quantify the plutonium (Pu) mass in spent nuclear fuel assemblies and to detect the diversion of pins with non-destructive assay (NDA) methods. NRF is one of 14 NDA techniques being researched. The methodology for performing and analyzing quantitative NRF measurements was developed for determining Pu mass in SNF and is extensively discussed in this report. The same methodology was applied to the assessment of NRF for the measurement of 235U enrichment and the determination of 239Pu in MOX fuel. The analysis centers on determining suitable NRF measurement methods, measurement capabilities that could be realized with currently available instrumentation, and photon source and detector requirements for achieving useful NDA capabilities.
Book Synopsis Examining 239Pu and 240Pu Nuclear Resonance Fluorescence Measurements on Spent Fuel for Nuclear Safeguards by :
Download or read book Examining 239Pu and 240Pu Nuclear Resonance Fluorescence Measurements on Spent Fuel for Nuclear Safeguards written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Potential National Security Applications of Nuclear Resonance Fluorescence Methods by :
Download or read book Potential National Security Applications of Nuclear Resonance Fluorescence Methods written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this report is to document the initial investigation into the possible research issues related to the development of NRF-based national security applications. The report discusses several potential applications ranging from measuring uranium enrichment in UF6 canisters to characterization of gas samples. While these applications are varied, there are only a few research issues that need to be addressed to understand the limitation of NRF in solving these problems. These research issues range from source and detector development to measuring small samples. The next effort is to determine how best to answer the research issues, followed by a prioritization of those questions to ensure that the most important are addressed. These issues will be addressed through either analytical calculations, computer simulations, analysis of previous data or collection of new measurements. It will also be beneficial to conduct a thorough examination of a couple of the more promising applications in order to develop concrete examples of how NRF may be applied in specific situations. The goals are to develop an understanding of whether the application of NRF is limited by technology or physics in addressing national security applications, to gain a motivation to explore those possible applications, and to develop a research roadmap so that those possibilities may be made reality.
Book Synopsis Preliminary Study of the Efficacy of Using Nuclear Resonance Fluorescence with Quasi-Monoenergetic Gamma-Ray Sources for Nuclear Safeguards Assay by :
Download or read book Preliminary Study of the Efficacy of Using Nuclear Resonance Fluorescence with Quasi-Monoenergetic Gamma-Ray Sources for Nuclear Safeguards Assay written by and published by . This book was released on 2011 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have studied the efficacy of using nuclear resonance fluorescence (NRF)-based techniques to assay spent nuclear fuel for Pu content using quasi-monoenergetic sources. We have developed two techniques to precisely determine the Pu content in a fuel rod/pin. One of our approaches is virtually free of systematic uncertainties. Using analytical models, we have determined the amount of time required to measure the Pu content in spent nuclear fuel rods and spent fuel assemblies to within 1% precision. We note that Pu content can be determined in a fuel assembly about as fast as in a single fuel pin. The performance of NRF-based assay techniques with improved photon sources, which are currently under development, will also estimated. For follow-on research we propose to: (1) Construct research prototype detection systems for both of the NRF-based assay systems proposed in this paper and measure their calibration curves; (2) Determine the systematic errors associated with both assay methods, explore ways to reduce the errors and fold the results into future performance calculations; (3) Develop an algorithm to assay a fuel assembly; (4) Perform validation measurements using a single pin and scaled assemblies; (5) Research and develop current-mode detection and/or threshold detection techniques to improve assay times; (6) Characterize the flux of newly constructed sources and fold the results into the calculations presented here to determine the feasibility of a variety of proposed sources; and (7) Collaborate with others in the safeguards community to build a prototype system and perform an NRF-based assay demonstration on spent fuel.
Book Synopsis Nuclear Resonance Fluorescence for Nuclear Materials Assay by : Brian Joseph Quiter
Download or read book Nuclear Resonance Fluorescence for Nuclear Materials Assay written by Brian Joseph Quiter and published by . This book was released on 2010 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation examines the measurement of nuclear resonance fluorescence gamma-rays as a technique to non-destructively determine isotopic compositions of target materials that are of interest for nuclear security applications. The physical processes that can result in non-resonant background to nuclear resonance fluorescence measurements are described and investigated using a radiation transport computer code that relies on the Monte Carlo technique, MCNPX. The phenomenon of nuclear resonance fluorescence is discussed with consideration of the angular distributions of resonance emissions, the effects of nuclear recoil, and the influence of thermal motion. Models describing two ways of measuring nuclear resonance fluorescence rates in materials are considered. First the measurement of back-scattered photons is considered. In this type of measurement, the portion of the interrogating photon beam that is scattered into large relative angles is measured. When the radioactivity of the target can be overcome by shielding or by use of intense photon sources, direct measurement of gamma-rays, emitted during nuclear resonance fluorescence can provide quantitative signatures that appear to be useful for applications such as forensic age-dating of large radiological sources. However, if the target radioactivity is too intense, as in the case for most spent nuclear fuel, a second measurement type, where indirect measurement of transmitted resonant-energy photons can also provide quantitative information. This method allows radiation detectors to be better-shielded from target radioactivity, but suffers from a slower accrual rate of statistical confidence. The models described herein indicate that very intense photon sources and large high-resolution detector arrays would be needed to measure 239Pu content in spent fuel to precisions desired by nuclear safeguards organizations. However, the rates at which statistics accrue are strongly proportional to the strengths of the resonances, and measurement of a plutonium isotope with stronger resonances may provide more practical measurement rates. The model for predicting relative detection rates of nuclear resonance fluorescence gamma-rays in the transmission measurement was experimentally tested using the 238U in a mixture of depleted uranium and lead as a surrogate for 239Pu in spent fuel. The experiment indicated that the model was approximately correct, but that the process of notch refilling, which was excluded from the initial model, appears to be visible. Data files of the computer code, MCNPX, were modified to allow for nuclear resonance fluorescence to be simulated and a bug in the code was repaired to allow the code to more accurately simulate non-resonant elastic photon scattering. Simulations using this modified version of MCNPX have indicated that the magnitude of the notch refill process is comparable to that of the difference between the analytical model and the experimental data.
Book Synopsis Applications of Photonuclear Physics for International Safeguards and Security by :
Download or read book Applications of Photonuclear Physics for International Safeguards and Security written by and published by . This book was released on 2010 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of nuclear resonance fluorescence based applications are presented. Important for these applications are data for isotopes such as 239Pu. Nuclear resonance fluorescence measurements of 239Pu were performed at the free electron laser facility at UC Santa Barbara using photons from a bremsstrahlung beam with an endpoint energies between 4.0 MeV and 5.5 MeV. Though no discrete states with significant confidence level were measured, we have excluded the region above 27(3) eV-barns, or 4-sigma, where we would expect only a small chance of false positives. Details of the measurements and the results are presented here.
Book Synopsis Assessment of Nuclear Resonance Fluorescence for Spent Nuclear Fuel Assay by :
Download or read book Assessment of Nuclear Resonance Fluorescence for Spent Nuclear Fuel Assay written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of gamma rays with specific energies that are characteristic of the emitting isotope. NRF promises the unique capability of directly quantifying a specific isotope without the need for unfolding the combined responses of several fissile isotopes as is required in other measurement techniques. We have analyzed the potential of NRF as a non-destructive analysis technique for quantitative measurements of Pu isotopes in spent nuclear fuel (SNF). Given the low concentrations of 239Pu in SNF and its small integrated NRF cross sections, the main challenge in achieving precise and accurate measurements lies in accruing sufficient counting statistics in a reasonable measurement time. Using analytical modeling, and simulations with the radiation transport code MCNPX that has been experimentally tested recently, the backscatter and transmission methods were quantitatively studied for differing photon sources and radiation detector types. Resonant photon count rates and measurement times were estimated for a range of photon source and detection parameters, which were used to determine photon source and gamma-ray detector requirements. The results indicate that systems based on a bremsstrahlung source and present detector technology are not practical for high-precision measurements of 239Pu in SNF. Measurements that achieve the desired uncertainties within hour-long measurements will either require stronger resonances, which may be expressed by other Pu isotopes, or require quasi-monoenergetic photon sources with intensities that are approximately two orders of magnitude higher than those currently being designed or proposed. This work is part of a larger effort sponsored by the Next Generation Safeguards Initiative to develop an integrated instrument, comprised of individual NDA techniques with complementary features, that is fully capable of determining Pu mass in spent fuel assemblies.
Book Synopsis Nuclear Resonance Fluorescence for Materials Assay by :
Download or read book Nuclear Resonance Fluorescence for Materials Assay written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper discusses the use of nuclear resonance fluorescence (NRF) techniques for the isotopic and quantitative assaying of radioactive material. Potential applications include age-dating of an unknown radioactive source, pre- and post-detonation nuclear forensics, and safeguards for nuclear fuel cycles Examples of age-dating a strong radioactive source and assaying a spent fuel pin are discussed. The modeling work has ben performed with the Monte Carlo radiation transport computer code MCNPX, and the capability to simulate NRF has bee added to the code. Discussed are the limitations in MCNPX's photon transport physics for accurately describing photon scattering processes that are important contributions to the background and impact the applicability of the NRF assay technique.
Book Synopsis Transmission Nuclear Resonance Fluorescence Measurements of 238U in Thick Targets by :
Download or read book Transmission Nuclear Resonance Fluorescence Measurements of 238U in Thick Targets written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Transmission nuclear resonance fluorescence measurements were made on targets consisting of Pb and depleted U with total areal densities near 86 g/cm2. The 238U content n the targets varied from 0 to 8.5percent (atom fraction). The experiment demonstrates the capability of using transmission measurements as a non-destructive technique to identify and quantify the presence of an isotope in samples with thicknesses comparable to he average thickness of a nuclear fuel assembly. The experimental data also appear to demonstrate the process of notch refilling with a predictable intensity. Comparison of measured spectra to previous backscatter 238U measurements indicates general agreement in observed excited states. Two new 238U excited states and possibly a third state have also been observed.
Book Synopsis Final Report for Nuclear Resonance Fluorescence Measurements of 239Pu Above 2.5 MeV. by :
Download or read book Final Report for Nuclear Resonance Fluorescence Measurements of 239Pu Above 2.5 MeV. written by and published by . This book was released on 2009 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear Resonance Fluorescence measurements were performed at the free electron laser facility at UC Santa Barbara using a bremsstrahlung beam. Three endpoint energies were chosen for the bremsstrahlung to cover as much area above 2.5 MeV as possible. We were able to set an upper limit of NRF state strengths between 2.5 and 3.8 MeV at roughly 38(5) eV barns at the 4-sigma level and 9(2) eV barns at the 1-sigma level. Published results on states near 2.4 MeV indicate strengths about 10(2) eV barns. Details of the results are presented in this report.
Book Synopsis Nuclear Resonance Fluorescence to Measure Plutonium Mass in Spent Nuclear Fuel by :
Download or read book Nuclear Resonance Fluorescence to Measure Plutonium Mass in Spent Nuclear Fuel written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Next Generation Safeguard Initiative (NGSI) of the U.S Department of Energy is supporting a multi-lab/university collaboration to quantify the plutonium (Pu) mass in spent nuclear fuel (SNF) assemblies and to detect the diversion of pins with non-destructive assay (NDA) methods. The following 14 NDA techniques are being studied: Delayed Neutrons, Differential Die-Away, Differential Die-Away Self-Interrogation, Lead Slowing Down Spectrometer, Neutron Multiplicity, Passive Neutron Albedo Reactivity, Total Neutron (Gross Neutron), X-Ray Fluorescence, 252Cf Interrogation with Prompt Neutron Detection, Delayed Gamma, Nuclear Resonance Fluorescence, Passive Prompt Gamma, Self-integration Neutron Resonance Densitometry, and Neutron Resonance Transmission Analysis. Understanding and maturity of the techniques vary greatly, ranging from decades old, well-understood methods to new approaches. Nuclear Resonance Fluorescence (NRF) is a technique that had not previously been studied for SNF assay or similar applications. Since NRF generates isotope-specific signals, the promise and appeal of the technique lies in its potential to directly measure the amount of a specific isotope in an SNF assay target. The objectives of this study were to design and model suitable NRF measurement methods, to quantify capabilities and corresponding instrumentation requirements, and to evaluate prospects and the potential of NRF for SNF assay. The main challenge of the technique is to achieve the sensitivity and precision, i.e., to accumulate sufficient counting statistics, required for quantifying the mass of Pu isotopes in SNF assemblies. Systematic errors, considered a lesser problem for a direct measurement and only briefly discussed in this report, need to be evaluated for specific instrument designs in the future. Also, since the technical capability of using NRF to measure Pu in SNF has not been established, this report does not directly address issues such as cost, size, development time, nor concerns related to the use of Pu in measurement systems. This report discusses basic NRF measurement concepts, i.e., backscatter and transmission methods, and photon source and [gamma]-ray detector options in Section 2. An analytical model for calculating NRF signal strengths is presented in Section 3 together with enhancements to the MCNPX code and descriptions of modeling techniques that were drawn upon in the following sections. Making extensive use of the model and MCNPX simulations, the capabilities of the backscatter and transmission methods based on bremsstrahlung or quasi-monoenergetic photon sources were analyzed as described in Sections 4 and 5. A recent transmission experiment is reported on in Appendix A. While this experiment was not directly part of this project, its results provide an important reference point for our analytical estimates and MCNPX simulations. Used fuel radioactivity calculations, the enhancements to the MCNPX code, and details of the MCNPX simulations are documented in the other appendices.
Book Synopsis Passive Nondestructive Assay of Nuclear Materials by : Doug Reilly
Download or read book Passive Nondestructive Assay of Nuclear Materials written by Doug Reilly and published by . This book was released on 1991 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Safeguards Techniques and Equipment by : International Atomic Energy Agency
Download or read book Safeguards Techniques and Equipment written by International Atomic Energy Agency and published by . This book was released on 2011 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1990s saw significant developments in the global non-proliferation landscape, resulting in a new period of safeguards development. The current publication, which is the second revision and update of IAEA/NVS/1, is intended to give a full and balanced description of the safeguards techniques and equipment used for nuclear material accountancy, containment and surveillance measures, environmental sampling, and data security. New features include a section on new and novel technologies. As new verification measures continue to be developed, the material in this book will be reviewed periodically and updated versions issued.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1967 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Handbook of Nuclear Chemistry by : Attila Vértes
Download or read book Handbook of Nuclear Chemistry written by Attila Vértes and published by Springer Science & Business Media. This book was released on 2010-12-10 with total page 3693 pages. Available in PDF, EPUB and Kindle. Book excerpt: This revised and extended 6 volume handbook set is the most comprehensive and voluminous reference work of its kind in the field of nuclear chemistry. The Handbook set covers all of the chemical aspects of nuclear science starting from the physical basics and including such diverse areas as the chemistry of transactinides and exotic atoms as well as radioactive waste management and radiopharmaceutical chemistry relevant to nuclear medicine. The nuclear methods of the investigation of chemical structure also receive ample space and attention. The international team of authors consists of scores of world-renowned experts - nuclear chemists, radiopharmaceutical chemists and physicists - from Europe, USA, and Asia. The Handbook set is an invaluable reference for nuclear scientists, biologists, chemists, physicists, physicians practicing nuclear medicine, graduate students and teachers - virtually all who are involved in the chemical and radiopharmaceutical aspects of nuclear science. The Handbook set also provides further reading via the rich selection of references.
Book Synopsis The New Nuclear Forensics by : Vitaly Fedchenko
Download or read book The New Nuclear Forensics written by Vitaly Fedchenko and published by Oxford University Press. This book was released on 2015 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear material changes its form and properties as it moves through the nuclear fuel cycle, from one facility to another. Each step of the fuel cycle or each use of the material will inevitably leave its mark. The science of determining the history of a sample of nuclear material through the study of these characteristics is known as nuclear forensics. While nuclear forensic analysis has normally been associated with investigations and prosecutions in the contextof trafficking of nuclear materials or nuclear terrorism, it had wider applications in in national security contexts, such as nuclear non-proliferation, disarmament, and arms control. The New Nuclear Forensics is the first book to give a definitive guide to this broader definition of nuclear forensic analysis. This book describes the various methods used in nuclear forensics, giving first a broad introduction to the process followed by details of relevant measurement techniques and procedures. In each case, the advantages and limitations are outlined. To put these methods in context, the book also recounts the history of the discipline anddescribes the diverse contemporary applications of nuclear forensics.
