Download or read book Further Evaluation of the Neutron Resonance Transmission Analysis NRTA Technique for Assaying Plutonium in Spent Fuel written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an end-of-year report (Fiscal Year (FY) 2011) for the second year of effort on a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The second-year goals for this project included: (1) assessing the neutron source strength needed for the NRTA technique, (2) estimating count times, (3) assessing the effect of temperature on the transmitted signal, (4) estimating plutonium content in a spent fuel assembly, (5) providing a preliminary assessment of the neutron detectors, and (6) documenting this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes work performed over a nine month period from January-September 2011 and is to be considered a follow-on or add-on report to our previous published summary report from December 2010 (INL/EXT-10-20620).

Download or read book Assessing the Feasibility of Using Neutron Resonance Transmission Analysis NRTA for Assaying Plutonium in Spent Fuel Assemblies written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron resonance transmission analysis (NRTA) is an active-interrogation nondestructive assay (NDA) technique capable of assaying spent nuclear fuel to determine plutonium content. Prior experimental work has definitively shown the technique capable of assaying plutonium isotope composition in spent-fuel pins to a precision of approximately 3%, with a spatial resolution of a few millimeters. As a Grand Challenge to investigate NDA options for assaying spent fuel assemblies (SFAs) in the commercial fuel cycle, Idaho National Laboratory has explored the feasibility of using NRTA to assay plutonium in a whole SFA. The goal is to achieve a Pu assay precision of 1%. The NRTA technique uses low-energy neutrons from 0.1-40 eV, at the bottom end of the actinide-resonance range, in a time-of-flight arrangement. Isotopic composition is determined by relating absorption of the incident neutrons to the macroscopic cross-section of the actinides of interest in the material, and then using this information to determine the areal density of the isotopes in the SFA. The neutrons used for NRTA are produced using a pulsed, accelerator-based neutron source. Distinguishable resonances exist for both the plutonium (239,240,241,242Pu) and uranium (235,236,238U) isotopes of interest in spent fuel. Additionally, in this energy range resonances exists for six important fission products (99Tc, 103Rh, 131Xe, 133Cs, 145Nd, and 152Sm) which provide additional information to support spent fuel plutonium assay determinations. Based on extensive modeling of the problem using Monte Carlo-based simulation codes, our preliminary results suggest that by rotating an SFA to acquire four symmetric views, sufficient neutron transmission can be achieved to assay a SFA. In this approach multiple scan information for the same pins may also be unfolded to potentially allow the determination of plutonium for sub-regions of the assembly. For a 17? 17 pressurized water reactor SFA, a simplistic preliminary analysis indicates the mass of 239Pu may be determined with a precision on the order of 5%, without the need for operator-supplied fuel information or operational histories. This paper will present our work to date on this topic, indicate our preliminary findings for a conceptual assay approach, discuss resilience against spoofing, and outline our future plans for evaluating the NRTA technique for SFA plutonium determination.

Download or read book Neutron Resonance Transmission Analysis NRTA written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron Resonance Transmission Analysis (NRTA) is an analytical technique that uses neutrons to assay the isotopic content of bulk materials. The technique uses a pulsed accelerator to produce an intense, short pulse of neutrons in a time-of-flight configuration. These neutrons, traveling at different speeds according to their energy, can be used to interrogate a spent fuel (SF) assembly to determine its plutonium content. Neutron transmission through the assembly is monitored as a function of neutron energy (time after the pulse), similar to the way neutron cross-section data is often collected. The transmitted neutron intensity is recorded as a function of time, with faster (higher-energy) neutrons arriving first and slower (lower-energy) neutrons arriving later. The low-energy elastic scattering and absorption resonances of plutonium and other isotopes modulate the transmitted neutron spectrum. Plutonium content in SF can be determined by analyzing this attenuation. Work is currently underway at Idaho National Laboratory, as a part of United States Department of Energy's Next Generation Safeguards Initiative (NGSI), to investigate the NRTA technique and to assess its feasibility for quantifying the plutonium content in SF and for determining the diversion of SF pins from assemblies. Preliminary results indicate that NRTA has great potential for being able to assay intact SF assemblies. Operating in the 1-40 eV range, it can identify four plutonium isotopes (239, 240, 241, & 242Pu), three uranium isotopes (235, 236, & 238U), and six resonant fission products (99Tc, 103Rh, 131Xe, 133Cs, 145Nd, and 152Sm). It can determine the areal density or mass of these isotopes in single- or multiple-pin integral transmission scans. Further, multiple observables exist to allow the detection of material diversion (pin defects) including fast-neutron and x-ray radiography, gross-transmission neutron counting, plutonium resonance absorption analysis, and fission-product resonance absorption analysis. Initial benchmark modeling has shown excellent agreement with previously published experimental data for measurements of individual SF pins where plutonium assays were experimentally demonstrated to have a precision of better than 3%.

Download or read book Neutron Resonance Transmission Analysis NRTA written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an end-of-year report for a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The first-year goals for this project were modest and included: 1) developing a zero-order MCNP model for the NRTA technique, simulating data results presented in the literature, 2) completing a preliminary set of studies investigating important design and performance characteristics for the NRTA measurement technique, and 3) documentation of this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes a nine month period of work.

Download or read book A Second Look at Neutron Resonance Transmission Analysis as a Spent Fuel NDA Technique written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many different nondestructive analysis techniques are currently being investigated as a part of the United States Department of Energy's Next Generation Safeguards Initiative (NGSI) seeking methods to quantify plutonium in spent fuel. Neutron Resonance Transmission Analysis (NRTA) is one of these techniques. Having first been explored in the mid-1970s for the analysis of individual spent-fuel pins a second look, using advanced simulation and modeling methods, is now underway to investigate the suitability of the NRTA technique for assaying complete spent nuclear fuel assemblies. The technique is similar to neutron time-of-flight methods used for cross-section determinations but operates over only the narrow 0.1-20 eV range where strong, distinguishable resonances exist for both the plutonium (239, 240, 241,242Pu) and uranium (235,236,238U) isotopes of interest in spent fuel. Additionally, in this energy range resonances exists for six important fission products (99Tc, 103Rh, 131Xe, 133Cs, 145Nd, and 152Sm) which provide additional information to support spent fuel plutonium assay determinations. Initial modeling shows excellent agreement with previously published experimental data for measurements of individual spent-fuel pins where plutonium assays were demonstrated to have a precision of 2-4%. Within the simulation and modeling analyses of this project scoping studies have explored fourteen different aspects of the technique including the neutron source, drift tube configurations, and gross neutron transmission as well as the impacts of fuel burn up, cooling time, and fission-product interferences. These results show that NRTA may be a very capable experimental technique for spent-fuel assay measurements. The results suggest sufficient transmission strength and signal differentiability is possible for assays through up to 8 pins. For an 8-pin assay (looking at an assembly diagonally), 64% of the pins in a typical 17? 17 array of a pressurized water reactor fuel assembly can be part of a complete transmission assay measurement with high precision. Analysis of rows with up to 12 pins may also be feasible but with diminished precision. Preliminary data analysis of an NRTA simulation has demonstrated the simplicity of the technique.

Download or read book Nuclear Physics And Gamma ray Sources For Nuclear Security And Nonproliferation Proceedings Of The International Symposium written by Takehito Hayakawa and published by World Scientific. This book was released on 2014-10-24 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear nonproliferation is a critical global issue. A key technological challenge to ensuring nuclear nonproliferation and security is the detection of long-lived radioisotopes and fissionable nuclides in a non-destructive manner. This technological challenge requires new methods for detecting relevant nuclides and the development of new quantum-beam sources. For example, one new method that has been proposed and studied is nuclear resonance fluorescence with energy-tunable, monochromatic gamma-rays generated by Compton scattering of laser photons with electrons.The development of new methods requires the help of researchers from a wide range of fields, such as nuclear physics, accelerator physics, laser physics, etc. Furthermore, any new method must be compatible with the requirements of administrators and nuclear-material inspectors.

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.

Download or read book Determination of Plutonium Content in Spent Fuel with Nondestructive Assay written by and published by . This book was released on 2009 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are a variety of reasons for quantifying plutonium (Pu) in spent fuel such as independently verifying the Pu content declared by a regulated facility, making shipper/receiver mass declarations, and quantifying the input mass at a reprocessing facility. As part of the Next Generation Safeguards Initiative, NA-241 has recently funded a multilab/university collaboration to determine the elemental Pu mass in spent fuel assemblies. This research effort is anticipated to be a five year effort: the first part of which is a two years Monte Carlo modeling effort to integrate and down-select among 13 nondestructive assay (NDA) technologies, followed by one year for fabricating instruments and then two years for measuring spent fuel. This paper gives a brief overview of the approach being taken for the Monte Carlo research effort. In addition, preliminary results for the first NDA instrument studied in detail, delayed neutron detection, will be presented. In order to cost effectively and robustly model the performance of several NDA techniques, an"assembly library" was created that contains a diverse range of pressurized water reactor spent fuel assemblies (burnup, enrichment, cooling time) similar to that which exists in spent pools today and in the future, diversion scenarios that capture a range of possible rod removal options, spatial and isotopic detail needed to accurately quantify the capability of all the NDA techniques so as to enable integration. Integration is being designed into this study from the beginning since it is expected that the best performance will be obtained by combining a few NDA techniques. The performance of each instrument will be quantified for the full assembly library in three different media: air, water and borated water. In this paper the preliminary capability of delayed neutron detection will be quantified for the spent fuel library for all three media. The 13 NDA techniques being researched are the following: Delayed Gamma, Delayed Neutrons, Differential Die-Away, Differential Die-Away Self-Interrogation, Lead Slowing Down Spectrometer, Neutron Multiplicity, Nuclear Resonance Fluorescence, Passive Prompt Gamma, Passive Neutron Albedo Reactivity, Self-integration Neutron Resonance Densitometry, Total Neutron (Gross Neutron), X-Ray Fluorescence, 252Cf Interrogation with Prompt Neutron Detection.

Download or read book Neutron Resonance Spectroscopy for the Characterisation of Materials and Objects written by and published by . This book was released on 2014 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of neutron resonance spectroscopy to investigate and study properties of materials and objects is the basis of neutron resonance transmission analysis (NRTA) and neutron resonance capture analysis (NRCA). NRTA and NRCA are non-destructive methods to determine the elemental and isotopic composition without the need of any sample preparation and resulting in a negligible residual activity. The basic principles of NRTA and NRCA are explained. The use of NRTA and NRCA to determine the elemental composition of archaeological objects and to characterise nuclear materials is reviewed. Other applications of neutron resonance spectroscopy such as imaging, detection of explosives and drugs and thermometry are briefly discussed. A combination of NRTA and NRCA, referred to as Neutron Resonance Densitometry (NRD), is presented as a non-destructive method to quantify nuclear material, in particular the amount of special nuclear material in particle-like debris of melted fuel that is formed in severe nuclear accidents. Finally the importance of accurate nuclear resonance parameters for these applications is discussed and the performance of NRTA for the characterisation of nuclear material in the presence of matrix material is assessed.

Download or read book Nondestructive Assay Methods for Irradiated Nuclear Fuels written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is a review of the status of nondestructive assay (NDA) methods used to determine burnup and fissile content of irradiated nuclear fuels. The gamma-spectroscopy method measures gamma activities of certain fission products that are proportional to the burnup. Problems associated with this method are migration of the fission products and gamma-ray attenuation through the relatively dense fuel material. The attenuation correction is complicated by generally unknown activity distributions within the assemblies. The neutron methods, which usually involve active interrogation and prompt or delayed signal counting, are designed to assay the fissile content of the spent-fuel elements. Systems to assay highly enriched spent-fuel assemblies have been tested extensively. Feasibility studies have been reported of systems to assay light-water reactor spent-fuel assemblies. The slowing-down spectrometer and neutron resonance absorption methods can distinguish between the uranium and plutonium fissile contents, but they are limited to the assay of individual rods. We have summarized the status of NDA techniques for spent-fuel assay and present some subjects in need of further investigation. Accuracy of the burnup calculations for power reactors is also reviewed.

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.

Download or read book Determining Plutonium Mass in Spent Fuel with Non destructive Assay Techniques NGSU Research Overview and Update on 6 NDA Techniques written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This poster is one of two complementary posters. The Next Generation Safeguards Initiative (NGSI) of the U.S. DOE has initiated a multi-lab/university collaboration to quantify the plutonium (Pu) mass in, and detect the diversion of pins from, spent nuclear fuel assemblies with non-destructive assay (NDA). This research effort has the goal of quantifying the capability of 14 NDA techniques as well as training a future generation of safeguards practitioners. By November of 2010, we will be 1.5 years into the first phase (2.5 years) of work. This first phase involves primarily Monte Carlo modelling while the second phase (also 2.5 years) will focus on experimental work. The goal of phase one is to quantify the detection capability of the various techniques for the benefit of safeguard technology developers, regulators, and policy makers as well as to determine what integrated techniques merit experimental work, We are considering a wide range of possible technologies since our research horizon is longer term than the focus of most regulator bodies. The capability of all of the NDA techniques will be determined for a library of 64 17 x 17 PWR assemblies [burnups (15, 30, 45, 60 GWd/tU), initial enrichments (2, 3, 4, 5%) and cooling times (1, 5, 20, 80 years)]. The burnup and cooling time were simulated with each fuel pin being comprised of four radial regions. In this paper an overview of the purpose will be given as well as a technical update on the following 6 neutron techniques: 252Cf Interrogation with Prompt Neutron Detection, Delayed Neutrons, Differential Die-Away, Differential Die-Away Self-Interrogation, Passive Neutron Albedo Reactivity, Self-Integration Neutron Resonance Densitometry. The technical update will quantify the anticipated performance of each technique for the 64 assemblies of the spent fuel library.

Download or read book Nondestructive Spent Fuel Assay Using Nuclear Resonance Fluorescence written by and published by . This book was released on 2009 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantifying the isotopic composition of spent fuel is an important challenge and essential for many nuclear safeguards applications, such as independent verification of the Pu content declared by a regulated facility, shipper/receiver measurements, and quantifying isotopic input masses at a reprocessing facility. As part of the Next Generation Safeguards Initiative, NA-241 has recently funded a multilab/university collaboration to investigate a variety of nondestructive methods for determining the elemental Pu mass in spent fuel assemblies. Nuclear resonance fluorescence (NRF) is one of the methods being investigated. First modeling studies have been performed to investigate the feasibility of assaying a single fuel pin using a bremsstrahlung photon source. MCNPX modeling results indicate that NRF signals are significantly more intense than the background due to scattered interrogation photons even for isotopes with concentrations below 1percent. However, the studies revealed that the dominant contribution to the background is elastic scattering, which is currently not simulated by MCNPX. Critical to this effort, we have added existing NRF data to the MCNPX photonuclear data files and are now able to incorporate NRF physics into MCNPX simulations. Addition of the non-resonant elastic scattering data to MCNPX is in progress. Assaying fuel assemblies with NRF poses additional challenges: photon penetration through the assembly is small and the spent fuel radioactive decay and neutron activity lead to significantly higher backgrounds. First modeling studies to evaluate the efficacy of NRF for assaying assemblies have been initiated using the spent fuel assembly library created at the Los Alamos National Laboratory (LANL).

Download or read book An Integrated Approach for Determining Plutonium Mass in Spent Fuel Assemblies with Nondestructive Assay written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: There are a variety of reasons for quantifying plutonium (Pu) in spent fuel. Below, five motivations are listed: (1) To verify the Pu content of spent fuel without depending on unverified information from the facility, as requested by the IAEA ('independent verification'). New spent fuel measurement techniques have the potential to allow the IAEA to recover continuity of knowledge and to better detect diversion. (2) To assure regulators that all of the nuclear material of interest leaving a nuclear facility actually arrives at another nuclear facility ('shipper/receiver'). Given the large stockpile of nuclear fuel at reactor sites around the world, it is clear that in the coming decades, spent fuel will need to be moved to either reprocessing facilities or storage sites. Safeguarding this transportation is of significant interest. (3) To quantify the Pu in spent fuel that is not considered 'self-protecting.' Fuel is considered self-protecting by some regulatory bodies when the dose that the fuel emits is above a given level. If the fuel is not self-protecting, then the Pu content of the fuel needs to be determined and the Pu mass recorded in the facility's accounting system. This subject area is of particular interest to facilities that have research-reactor spent fuel or old light-water reactor (LWR) fuel. It is also of interest to regulators considering changing the level at which fuel is considered self-protecting. (4) To determine the input accountability value at an electrochemical processing facility. It is not expected that an electrochemical reprocessing facility will have an input accountability tank, as is typical in an aqueous reprocessing facility. As such, one possible means of determining the input accountability value is to measure the Pu content in the spent fuel that arrives at the facility. (5) To fully understand the composition of the fuel in order to efficiently and safely pack spent fuel into a long-term repository. The NDA of spent fuel can be part of a system that cost-effectively meets the burnup credit needs of a repository. Behind each of these reasons is a regulatory structure with MC & A requirements. In the case of the IAEA, the accountable quantity is elemental plutonium. The material in spent fuel (fissile isotopes, fission products, etc.) emits signatures that provide information about the content and history of the fuel. A variety of nondestructive assay (NDA) techniques are available to quantify these signatures. The effort presented in this paper is investigation of the capabilities of 12 NDA techniques. For these 12, none is conceptually capable of independently determining the Pu content in a spent fuel assembly while at the same time being able to detect the diversion of a significant quantity of rods. For this reason the authors are investigating the capability of 12 NDA techniques with the end goal of integrating a few techniques together into a system that is capable of measuring Pu mass in an assembly. The work described here is the beginning of what is anticipated to be a five year effort: (1) two years of modeling to select the best technologies, (2) one year fabricating instruments and (3) two years measuring spent fuel. This paper describes the first two years of this work. In order to cost effectively and robustly model the performance of the 12 NDA techniques, an 'assembly library' was created. The library contains the following: (a) A diverse range of PWR spent fuel assemblies (burnup, enrichment, cooling time) similar to that which exists in spent pools today and in the future. (b) Diversion scenarios that capture a range of possible rod removal options. (c) The spatial and isotopic detail needed to accurately quantify the capability of all the NDA techniques so as to enable integration. It is our intention to make this library available to other researchers in the field for inter-comparison purposes. The performance of each instrument will be quantified for the full assembly library for measurements in three different media: air, water and borated water. The 12 NDA techniques being researched are the following: Delayed Gamma, Delayed Neutrons, Differential Die-Away, Lead Slowing Down Spectrometer, Neutron Multiplicity, Nuclear Resonance Fluorescence, Passive Prompt Gamma, Passive Neutron Albedo Reactivity, Self-integration Neutron Resonance Densitometry, Total Neutron (Gross Neutron), X-Ray Fluorescence, 252Cf Interrogation with Prompt Neutron Detection.

Download or read book Neutron Resonance Spectroscopy for the Characterisation of Materials and Objects written by P. Schillebeeckx and published by . This book was released on 2014 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of neutron resonance spectroscopy to investigate and study properties of materials and objects is the basis of neutron resonance transmission analysis (NRTA) and neutron resonance capture analysis (NRCA). NRTA and NRCA are non-destructive methods to determine the elemental and isotopic composition without the need of any sample preparation and resulting in a negligible residual activity. The basic principles of NRTA and NRCA are explained. The use of NRTA and NRCA to determine the elemental composition of archaeological objects and to characterise nuclear materials is reviewed. Other applications of neutron resonance spectroscopy such as imaging, detection of explosives and drugs and thermometry are briefly discussed. A combination of NRTA and NRCA, referred to as Neutron Resonance Densitometry (NRD), is presented as a non-destructive method to quantify nuclear material, in particular the amount of special nuclear material in particle-like debris of melted fuel that is formed in severe nuclear accidents. Finally the importance of accurate nuclear resonance parameters for these applications is discussed and the performance of NRTA for the characterisation of nuclear material in the presence of matrix material is assessed.

Download or read book Determining Plutonium in Spent Fuel with Nondestructive Assay Techniques written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: There are a variety of motivations for quantifying plutonium in used (spent) fuel assemblies by means of nondestructive assay including the following: shipper/receiver difference, input accountability at reprocessing facilities and burnup credit at repositories or fuel storage facilities. Twelve NDA techniques were identified that provide information about the composition of an assembly. Unfortunately, none of these techniques is capable of determining the Pu mass in an assembly on its own. However, it is expected that the Pu mass can be quantified by combining a few of the techniques. Determining which techniques to combine and estimating the expected performance of such a system is the purpose of the research effort recently begun. The research presented here is a complimentarily experimental effort. This paper will focus on experimental results of one of the twelve non-destructive assay techniques - passive neutron albedo reactivity. The passive neutron albedo reactivity techniques work by changing the multiplication the pin experiences between two separate measurements. Since a single spent fuel pin has very little multiplication, this is a challenging measurement situation for the technique. Singles and Doubles neutron count rate were measured at Oak Ridge National Laboratory for three different burnup pins to test the capability of the passive neutron albedo reactivity technique.

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1984-12 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: