Showing papers in "Nuclear Technology in 2011"
TL;DR: The version 6 of the Standardized Computer Analyses for Licensing Evaluation (SCALE) computer software system developed at Oak Ridge National Laboratory (ORNL) was released in February 2009 as mentioned in this paper.
Abstract: Version 6 of the Standardized Computer Analyses for Licensing Evaluation (SCALE) computer software system developed at Oak Ridge National Laboratory, released in February 2009, contains significant...
159 citations
TL;DR: The calculation of fuel isotopic compositions is essential to support design, safety analysis, and licensing of many components of the nuclear fuel cycle, from reactor physics and severe accident an... as discussed by the authors.
Abstract: The calculation of fuel isotopic compositions is essential to support design, safety analysis, and licensing of many components of the nuclear fuel cycle—from reactor physics and severe accident an...
139 citations
TL;DR: The Tools for Sensitivity and UNcertainty Analysis Methodology Implementation (TSUNAMI) modules calculate the sensitivity of keff or reactivity differences to the neutron cross-section as mentioned in this paper.
Abstract: In SCALE 6, the Tools for Sensitivity and UNcertainty Analysis Methodology Implementation (TSUNAMI) modules calculate the sensitivity of keff or reactivity differences to the neutron cross-section ...
82 citations
TL;DR: The Monte Carlo shielding analysis capabilities in SCALE 6 are centered on the Consistent Adjoint Driven Importance Sampling (CADIS) methodology, which is used to create an importance map for space/energy weight windows as well as a biased source distribution.
Abstract: Monte Carlo shielding analysis capabilities in SCALE 6 are centered on the CADIS methodology Consistent Adjoint Driven Importance Sampling. CADIS is used to create an importance map for space/energy weight windows as well as a biased source distribution. New to SCALE 6 are the Monaco functional module, a multi-group fixed-source Monte Carlo transport code, and the MAVRIC sequence (Monaco with Automated Variance Reduction Using Importance Calculations). MAVRIC uses the Denovo code (also new to SCALE 6) to compute coarse-mesh discrete ordinates solutions which are used by CADIS to form an importance map and biased source distribution for the Monaco Monte Carlo code. MAVRIC allows the user to optimize the Monaco calculation for a specify tally using the CADIS method with little extra input compared to a standard Monte Carlo calculation. When computing several tallies at once or a mesh tally over a large volume of space, an extension of the CADIS method called FW-CADIS can be used to help the Monte Carlo simulation spread particles over phase space to get more uniform relative uncertainties.
79 citations
TL;DR: The SCALE/TRITON as mentioned in this paper code sequence provides a powerful, robust, and rigorous approach for performing reactor physics analysis, including the ability to accurately predict the nuclide composition of depleted reactor fuel.
Abstract: The TRITON sequence of the SCALE code system provides a powerful, robust, and rigorous approach for performing reactor physics analysis. This paper presents a detailed description of TRITON in terms of its key components used in reactor calculations. The ability to accurately predict the nuclide composition of depleted reactor fuel is important in a wide variety of applications. These applications include, but are not limited to, the design, licensing, and operation of commercial/research reactors and spent-fuel transport/storage systems. New complex design projects such as next-generation power reactors and space reactors require new high-fidelity physics methods, such as those available in SCALE/TRITON, that accurately represent the physics associated with both evolutionary and revolutionary reactor concepts as they depart from traditional and well-understood light water reactor designs.
79 citations
TL;DR: In this paper, problem-independent multigroup (MG) libraries were processed from the evaluated nuclear data file ENDF/B using a generic flux spectrum, and the library data must be self-satisfactory.
Abstract: SCALE 6 includes several problem-independent multigroup (MG) libraries that were processed from the evaluated nuclear data file ENDF/B using a generic flux spectrum. The library data must be self-s...
56 citations
TL;DR: Development of the Monte Carlo solution technique and solution methodology as applied in both KENO codes is explained and performance of the codes is demonstrated using published benchmark problems.
Abstract: This paper describes the Monte Carlo codes KENO V.a and KENO-VI in SCALE that are primarily used to calculate multiplication factors and flux distributions of fissile systems. Both codes allow explicit geometric representation of the target systems and are used internationally for safety analyses involving fissile materials. KENO V.a has limiting geometric rules such as no intersections and no rotations. These limitations make KENO V.a execute very efficiently and run very fast. On the other hand, KENO-VI allows very complex geometric modeling. Both KENO codes can utilize either continuous-energy or multigroup cross-section data and have been thoroughly verified and validated with ENDF libraries through ENDF/B-VII.0, which has been first distributed with SCALE 6. Development of the Monte Carlo solution technique and solution methodology as applied in both KENO codes is explained in this paper. Available options and proper application of the options and techniques are also discussed. Finally, performance of the codes is demonstrated using published benchmark problems.
51 citations
TL;DR: Within the course of a hypothetical severe accident in a nuclear power plant, hydrogen can be generated in the primary circuit and released into the containment as mentioned in this paper, and considering the possibility of a de...
Abstract: Within the course of a hypothetical severe accident in a nuclear power plant, hydrogen can be generated in the primary circuit and released into the containment. Considering the possibility of a de...
41 citations
TL;DR: The 30-deg white neutron beam at the Research Center for Nuclear Physics (RCNP) cyclotron facility has been characterized as a probe suitable for testing of single event effects (SEE) in semiconduc... as mentioned in this paper.
Abstract: The 30-deg white neutron beam at the Research Center for Nuclear Physics (RCNP) cyclotron facility has been characterized as a probe suitable for testing of single-event effects (SEE) in semiconduc...
35 citations
TL;DR: The Halden Reactor Project (HRP) relies on extensive use of in-core instrumentation for both fuel and material testing in the HBWR as mentioned in this paper, and separate loop systems have been in...
Abstract: The Halden Reactor Project (HRP) relies on extensive use of in-core instrumentation for both fuel and material testing in the Halden Boiling Water Reactor (HBWR). Separate loop systems have been in...
33 citations
TL;DR: The project is being demonstrated through the development and implementation of a system that integrates signals from existing wired sensors and new wireless sensors to facilitate a holistic view of the health of equipment and processes in nuclear power reactors.
Abstract: Wireless sensors are becoming very popular in industrial processes for measurement and control, condition monitoring, predictive maintenance, and management of operational transients and accidents. In the last five years, many sensor manufacturers have teamed up with companies who make wireless transmitters, receivers, and network equipment to provide industrial facilities with integrated networks of wireless sensors that can be used to measure process temperature, pressure, vibration, humidity, and other parameters to improve process safety and efficiency, increase output, and optimize maintenance activities. Historically, the nuclear industry has been slower than others in implementing new technologies—wireless technologies are no exception. This is of course justified, as nuclear research and power reactors must perform a more thorough “due diligence” than other industries before they can adopt a new technology because of the increased safety and licensing requirements.This paper reports on a r...
TL;DR: In this paper, a Bayesian approach is proposed to estimate the most likely location of a source given a set of observed count rates, and a probabilistic representation accounts for uncertainty in the source location resulting from uncertainties in detector responses.
Abstract: Locating illicit radiological sources using gamma-ray or neutron detection is a key challenge for both homeland security and nuclear nonproliferation. Localization methods using an array of detectors or a sequence of observations in time and space must provide rapid results while accounting for a dynamic attenuating environment. In the presence of significant attenuation and scatter, more extensive numerical transport calculations in place of the standard analytical approximations may be required to achieve accurate results. Numerical adjoints based on deterministic transport codes provide relatively efficient detector response calculations needed to determine the most likely location of a true source given a set of observed count rates. Probabilistic representations account for uncertainty in the source location resulting from uncertainties in detector responses and the potential for nonunique solutions. A Bayesian approach improves on previous likelihood methods for source localization by allowi...
TL;DR: In this paper, the current state of instrumentation technologies in material test reactors (MTRs) in the world and summarizes ongoing research efforts to deploy new sensors are discussed. But, the authors focus on providing MTR users a wider range of parameter measurements with smaller, higher accuracy sensors.
Abstract: Over 50 years of nuclear fuels and materials irradiation testing has led to many countries developing significant improvements in instrumentation to monitor physical parameters and to control the test conditions in material test reactors (MTRs). Recently, there is increased interest to irradiate new materials and reactor fuels for advanced pressurized water reactors and Gen-IV reactor systems, such as sodium-cooled fast reactors, very high temperature reactors, supercritical water-cooled reactors, and gas-cooled fast reactors. This review paper documents the current state of instrumentation technologies in MTRs in the world and summarizes ongoing research efforts to deploy new sensors. As described in this paper, a wide range of sensors is available to measure key parameters of interest during fuels and materials irradiations in MTRs. Ongoing development efforts focus on providing MTR users a wider range of parameter measurements with smaller, higher accuracy sensors.
TL;DR: The U.S. Nuclear Regulatory Commission has undertaken a program to lay the groundwork for defining proactive actions to manage degradation of materials in light water reactors (LWRs).
Abstract: The Nuclear Regulatory Commission has undertaken a program to lay the groundwork for defining proactive actions to manage degradation of materials in light water reactors (LWRs). This paper discusses the U.S. Nuclear Regulatory Commission’s Proactive Management of Materials Degradation (PMMD) program and its application to nuclear power plant structures, systems and components. The PMMD program is examining LWR component materials and the degradation phenomena that affect them. Of particular interest is how such phenomena can be monitored to predict degradation and prevent component failure. Some forms of degradation, including some modes of stress corrosion cracking, are characterized by a long initiation time followed by a rapid growth phase. Monitoring such long-term degradation will require new non-destructive evaluation (NDE) methods and measurement procedures. A critical analysis of all reactor components is required to determine if new inspection strategies are required to effectively manage slow degradation mechanisms that may lead to component failure. As reactor lifetimes are extended, degradation mechanisms previously considered too long-term to be of consequence (such as concrete and wiring insulation degradation) may become more important. This paper includes a review of techniques with potential for sensing and monitoring degradation in its early stages and will concisely explain themore » basic principles of PMMD and its relationship to in-service inspection, condition based maintenance, and advanced diagnostics and prognostics.« less
TL;DR: An experimental facility for in situ measurements of high-temperature spectral emissivity of materials in environments of interest to the gas-cooled very high temperature reactor (VHTR) has been developed.
Abstract: An experimental facility for in situ measurements of high-temperature spectral emissivity of materials in environments of interest to the gas-cooled very high temperature reactor (VHTR) has been developed. The facility is capable of measuring emissivities of seven materials in a single experiment, thereby enhancing the accuracy in measurements due to even minor systemic variations in temperatures and environments. The system consists of a cylindrical silicon carbide (SiC) block with seven sample cavities and a deep blackbody cavity, a detailed optical system, and a Fourier transform infrared spectrometer. The reliability of the facility has been confirmed by comparing measured spectral emissivities of SiC, boron nitride, and alumina (Al2O3) at 600°C against those reported in literature. The spectral emissivities of two candidate alloys for VHTR, INCONEL® alloy 617 (INCONEL is a registered trademark of the Special Metals Corporation group of companies) and SA508 steel, in air environment at 700°C w...
TL;DR: For the supercritical CO2 Brayton cycle of a sodium-cooled fast reactor, the authors carried out surface reaction tests for sodium temperatures ranging from 200 to 600°C.
Abstract: For the supercritical CO2 Brayton cycle of a sodium-cooled fast reactor, we carried out surface reaction tests for sodium temperatures ranging from 200 to 600°C. Based on the test results, we found...
TL;DR: In this article, a diffusion-based kinetic model essential for design and operational analysis of spent nuclear fuel reduction has been developed, and the model considers the cathode side of the system.
Abstract: In this study, a diffusion-based kinetic model essential for design and operational analysis of spent nuclear fuel reduction has been developed. The model considers the cathode side of the system t...
TL;DR: A computational model of the Mark-IV electrorefiner is currently being developed as a joint project between Idaho National Laboratory, Korea Atomic Energy Research Institute, and Seoul National Univers as discussed by the authors, which can be found here.
Abstract: A computational model of the Mark-IV electrorefiner is currently being developed as a joint project between Idaho National Laboratory, Korea Atomic Energy Research Institute, Seoul National Univers
TL;DR: In this article, three triggered steam explosion experiments were performed in the TROI facility with a two-dimensional interaction vessel of 0.6m diameter in a 1.0m-deep water pool under atmospheric pressure.
Abstract: Three triggered steam explosion experiments were performed in the TROI facility with a two-dimensional interaction vessel of 0.6-m diameter. The melt compositions were pure zirconia (ZrO2), 70:30 (UO2:ZrO2 = 70:30 wt%) eutectic corium, and 50:50 noneutectic corium. All tests were performed in a 1.0-m-deep water pool under atmospheric pressure. The water temperature was maintained at room temperature. The melt mass released to the water pool was ~10 kg for each test. The tests with pure zirconia and 70:30 corium resulted in triggered steam explosions, while the test with 50:50 corium did not. However, a weak trace of a steam spike was detected with 50:50 corium with a fairly long delay time (~0.1 s) after an external triggering. The explosion efficiency was estimated from the dynamic load and dynamic pressure. The explosion efficiency was calculated to be 0.1% for zirconia and 0.04% for 70:30 corium. The explosivity of corium material was found to be rather low, compared to the simulant material (a...
TL;DR: In this paper, the authors report on the generation, collection, and characterization of carbon nanoparticles using a spark generator and a thermophoretic deposition cell, as well as environmental scanning electron microscopy and scanning mobility particle spectrometry.
Abstract: Nanoparticles can form during nuclear accidents as well as during normal nuclear reactor operations and can be both radioactive and nonradioactive. It is important to understand particle size characteristics, transport properties, and deposition in order to better predict the behaviors of, and effects due to, these particles in a reactor. Fission products can deposit (adsorb/absorb) on the graphite dust in the core [an amount of carbon dust is present in the Pebble Bed Modular Reactor (PBMR) because of graphite sphere abrasion] and can also be carried by the helium flow (together with some dust). Generating nanoparticles of desired shape, size, and purity for experimental purposes is difficult, and hence, there is a need for new and refined synthesis techniques. Nanoparticle generation using high-voltage electric sparks has become a technique of interest for a wide range of conducting materials, and particles with sizes ranging from a few nanometers up to microns have been generated in this manner in an aerosol state. Our purpose in this paper is to report on the generation, collection, and characterization of carbon nanoparticles. We have used a spark generator and a thermophoretic deposition cell, as well as environmental scanning electron microscopy, transmission electron microscopy, and scanning mobility particle spectrometry. We have explored a number of experimental conditions, and we find that one can generate and effectively collect test particles with a variety of different useful characteristics. We also discuss some computational fluid dynamics simulations of particle deposition in the thermophoretic deposition cell.
TL;DR: The Levenberg-Marquardt method is applied to the inverse transport problems of interface location identification, shield material identification, source composition identification, and material mass density identification in multilayered radioactive source/shield systems.
Abstract: Determining the components of a radioactive source/shield system using the system’s radiation signature, a type of inverse transport problem, is one of great importance in homeland security, materi...
TL;DR: The immense size and complex geometry of the ITER experimental fusion reactor require the development of special techniques that can accurately and efficiently perform neutronics simulations with m... as discussed by the authors, which is the basis for this paper.
Abstract: The immense size and complex geometry of the ITER experimental fusion reactor require the development of special techniques that can accurately and efficiently perform neutronics simulations with m...
TL;DR: In this article, the angular distribution of scattered photons is incorrect in MCNPX and MCNP5 because the incoherent and coherent form factors are obsolete, which affects all photon transport problems.
Abstract: The angular distribution of scattered photons is incorrect in MCNPX and MCNP5 because the incoherent and coherent form factors are obsolete. The obsolete data affect all photon transport problems w...
TL;DR: In 2002, the discovery of small-break loss-of-coolant accident (SBLOCA) was reported in this paper, which is the case of the Three Mile Island accident.
Abstract: Since the Three Mile Island accident, an important focus of pressurized water reactor (PWR) transient analyses has been a small-break loss-of-coolant accident (SBLOCA). In 2002, the discovery of th...
TL;DR: In this article, the Nevada Test Site (NTS) varnish samples were collected near three point sources of air pollution to determine if the varnishes contained a record of recent air pollution.
Abstract: Rock varnish samples were collected near three point sources of air pollution to determine if the varnish contained a record of recent air pollution. Samples were collected as follows: downwind of the Nevada Test Site (NTS); in the fallout pattern of the shuttered Mohave Power Plant, located in Laughlin, Nevada; and, near the operating Reid-Gardner Power Plant, just east of Las Vegas, Nevada. Analysis of the NTS rock varnish shows 240Pu/239Pu mass ratios as low as 0.0592 ± 0.0003 and 241Pu/239Pu ratios as low as 0.00063 ± 0.00004, compared to worldwide values of 0.18 ± 0.01 and 0.009 ± 0.002, respectively, clearly indicating that the varnish can be used as a forensic tool for identifying the source of air pollution, in this case the NTS. The samples collected in the plumes of the coal-fired power plants contain thorium and uranium, and have 232Th/238U mass ratios from 1 to 30, and concentrations from 5 to 755 ppm for Th and 1 to 578 ppm for U. The highest concentrations of these elements occur tog...
TL;DR: In this article, the CEA (French Nuclear Energy Commiss (CEA) has proposed an instrumentation for in-pile measurements of temperature, dimensions, pressure, or chemical analysis in innovative mediums.
Abstract: Optimizing the life cycle of nuclear systems under safety constraints requires high-performance experimental programs to reduce uncertainties on margins and limits In addition to improvement in modeling and simulation, innovation in instrumentation is crucial for analytical and integral experiments conducted in research reactorsSignificant efforts have been made recently to improve in-pile instrumentation for the benefit of material testing reactors The quality of nuclear research programs obviously relies on an excellent knowledge of their experimental environment, which constantly calls for better online determination of neutron and gamma flux But the combination of continuously increasing scientific requirements and new experimental domains—brought, for example, by Generation-IV programs—also necessitates major innovations for in-pile measurements of temperature, dimensions, pressure, or chemical analysis in innovative mediumsTo face these challenges, the CEA (French Nuclear Energy Commiss
TL;DR: In this paper, a tandem differential mobility analyzer (TDMA) was used to simultaneously measure both the size and charge dependent aerosol distributions, and the particle size distributions for negative and positive charges were observed.
Abstract: The role of charge on aerosol evolution and hence the nuclear source term has been an issue of interest, and there is a need for both experimental techniques and modeling for quantifying this role. Our focus here is on further exploration of a tandem differential mobility analyzer (TDMA) technique to simultaneously measure both the size and charge (positive, negative and neutral) dependent aerosol distributions. We have generated graphite, gold, silver, and palladium nanoparticles (aerosol) using a spark generator. We measure the electrical mobility-size distributions for these aerosols using a TDMA, and from these data we deduce the full charge-size distributions. We observe asymmetry in the particle size distributions for negative and positive charges. This asymmetry could have a bearing on the dynamics of charged aerosols, indicating that the assumption of symmetry for size distributions of negatively and positively charged particles in source term simulations may not be always appropriate. Also, the experimental technique should find applications in measurements of aerosol rate processes that are affected by both particle charge and size (e.g. coagulation, deposition, resuspension), and hence in modeling and simulation of the nuclear source term.
TL;DR: In this article, the optimal way to shield a compact, isotropic neutron source into a beam for active interrogation neutron systems was determined, and the restricted emission angle was defined.
Abstract: This research was conducted to determine the optimal way to shield a compact, isotropic neutron source into a beam for active interrogation neutron systems. To define the restricted emission angle ...
TL;DR: In this paper, the Hilbert-Huang Transform (HHT) was applied to the diagnosis and evaluation of electromechanica, and the results showed that the Hilbert Huang Transform can be used to solve time-frequency decomposition (TFD) problems.
Abstract: The work carried out by the authors consists of applying a modern time-frequency decomposition (TFD) tool, the Hilbert-Huang Transform (HHT), to the diagnosis and the evaluation of electromechanica...
TL;DR: A review of the disposal of irradiated beryllium can be found in this paper, where the authors review the processes that have been investigated or considered for improving the disposability of irradiate beryellium, and approaches for recycling.
Abstract: Beryllium plays important roles in nuclear facilities. Its neutron multiplication capability and low atomic weight make it very useful as a reflector in fission reactors. Its low atomic number and high chemical affinity for oxygen have led to its consideration as a plasma-facing material in fusion reactors. In both applications, the beryllium and the impurities in it become activated by neutrons, transmuting them to radionuclides, some of which are long-lived and difficult to dispose of. Also, gas production, notably helium and tritium, results in swelling, embrittlement, and cracking, which means that the beryllium must be replaced periodically, especially in fission reactors where dimensional tolerances must be maintained. It has long been known that neutron activation of inherent iron and cobalt in the beryllium results in significant {sup 60}Co activity. In 2001, it was discovered that activation of naturally occurring contaminants in the beryllium creates sufficient {sup 14}C and {sup 94}Nb to render the irradiated beryllium 'Greater-Than-Class-C' for disposal in U.S. radioactive waste facilities. It was further found that there was sufficient uranium impurity in beryllium that had been used in fission reactors up to that time that the irradiated beryllium had become transuranic in character, making it even more difficultmore » to dispose of. In this paper we review the extent of the disposal issue, processes that have been investigated or considered for improving the disposability of irradiated beryllium, and approaches for recycling.« less