Recent ucd_mnrc items

Phenotypic and genomic analyses of a fast neutron mutant population resource in soybean

Tue, 31 May 2011 00:00:00 +0000

Mutagenized populations have become indispensable resources for introducing variation and studying gene function in plant genomics research. In this study, fast neutron (FN) radiation was used to induce deletion mutations in the soybean (Glycine max) genome. Approximately 120,000 soybean seeds were exposed to FN radiation doses of up to 32 Gray units to develop over 23,000 independent M2 lines. Here, we demonstrate the utility of this population for phenotypic screening and associated genomic characterization of striking and agronomically important traits. Plant variation was cataloged for seed composition, maturity, morphology, pigmentation, and nodulation traits. Mutants that showed significant increases or decreases in seed protein and oil content across multiple generations and environments were identified. The application of comparative genomic hybridization (CGH) to lesion-induced mutants for deletion mapping was validated on a midoleate x-ray mutant, M23, with a known...

Periodic magnetic fieldas a polarized and focusing thermal neutron spectrometer and monochromator

Wed, 13 Jan 2010 00:00:00 +0000

A novel periodic magnetic field PMF optic is shown to act as a prism, lens, and polarizer for neutrons and particles with a magnetic dipole moment. The PMF has a two-dimensional field in the axial direction of neutron propagation. The PMF alternating magnetic field polarity provides strong gradients that cause separation of neutrons by wavelength axially and by spin state transversely. The spin-up neutrons exit the PMF with their magnetic spins aligned parallel to the PMF magnetic field, and are deflected upward and line focus at a fixed vertical height, proportional to the PMF period, at a downstream focal distance that increases with neutron energy. The PMF has no attenuation by absorption or scatter, as with material prisms or crystal monochromators. Embodiments of the PMF include neutron spectrometer or monochromator, and applications include neutron small angle scattering, crystallography, residual stress analysis, cross section measurements, and reflectometry. Presented...

Rocky Flats CAAS System Recalibrated, Retested, and Analyzed to Install in the Criticality Experiments Facility at the Nevada Test Site

Wed, 13 Jan 2010 00:00:00 +0000

Neutron detectors and control panels transferred from Rocky Flats Plant (RFP) were recalibrated and retested for redeployment to the CEF. Testing and calibration were successful with no failure to any equipment. Detector sensitivity was tested at the TRIGA reactor, and the response to thermal neutron flux was satisfactory. MCNP calculated minimum fission yield (~ 2 × 1015 fissions) was applied to determine the thermal flux at selected detector positions at the CEF. Thermal flux levels were greater than 6.39 × 106 (n/cm2-sec), which was about four orders of magnitude greater than the minimum alarm flux. Calculations of detector survivable distances indicate that, to be out of lethal area, detector needs to be placed greater than 15 ft away from the source. MCNP calculated flux/dose results were independently verified by COG. CAAS calibration and the testing confirmed that the RFP CAAS system is performing its functions as expected. New criteria for the CAAS detector placement...

Thermal Neutron Computed Tomography of Soil Water and Plant Roots

Mon, 17 Nov 2008 00:00:00 +0000

Neutron radiography is a noninvasive imaging technique that measures the attenuation of thermal neutrons, as is done with x-ray and γ-ray radiography, to characterize the internal composition of materials. Neutron and x-ray imaging are complementary techniques, with neutron imaging especially well suited for materials containing H atoms and other low-atomic-weight attenuating materials. Although neutron computed tomography (NCT) techniques are routinely used in engineering, relatively little is known about their application to soils. We developed new techniques that use thermal neutron attenuation to measure the spatial and temporal distribution of water in soils and near roots at near 0.5-mm spatial resolution or higher. The neutron source was a Mark II Triga Reactor at McClellan Nuclear Radiation Center in Sacramento, CA. After calibration using both deuterated and regular water, the effects of beam hardening and neutron scattering could be corrected for, provided that the...

Development of a Large-Scale Iodine-125 Production System at UC Davis/MNRC

Tue, 17 Jun 2008 00:00:00 +0000

The demand for iodine-125 (125I) as a medical radioisotope for use in the treatment of prostate cancer continues to increase. However, due to uncertainties with current commercial production facilities, potential supply issues have emerged prompting several reactors worldwide to consider the development and installation of large-scale 125I production facilities. In 2002, MNRC installed and operated successfully for ~ 1.5 years, a closed loop system using aluminum material for containment of the enriched 124Xe (99%) target during irradiation. However, problems with design features and restrictions on serviceability and repairs ultimately forced MNRC to abandon it as a first target failure resulted in high contamination levels in the whole system which further restricted personnel accessibility. Today, a new target and a multi-compartment (modular) transport and decay system with automatic operation and dispensing of high-level batches of 125I and with ready access for maintenance...

Reactor control system upgrade for the McClellan Nuclear Radiation Center

Wed, 3 Oct 2007 00:00:00 +0000

Argonne National Laboratory is currently developing a new reactor control system for the McClellan Nuclear Radiation Facility. This new control system not only provides the same functionality as the existing control system in terms of graphic displays of reactor process variables, data archival capability, and manual, automatic, pulse and square-wave modes of operation, but adds to the functionality of the previous control system by incorporating signal processing algorithms for the validation of sensors and automatic calibration and verification of control rod worth curves. With the inclusion of these automated features, the intent of this control system is not to replace the operator but to make the process of controlling the reactor easier and safer for the operator. For instance, an automatic control rod calibration method reduces the amount of time to calibrate control rods from days to minutes, increasing overall reactor utilization. The control rod calibration curve,...

Preprocessing of backprojection images in the McClellan Nuclear Radiation Center tomography system

Wed, 3 Oct 2007 00:00:00 +0000

Preprocessing of backprojection images in the McClellan Nuclear Radiation Center tomography system

Thermal hydraulic calculations to support increase in operating power in McClellan Nuclear Radiation Center(MNRC) TRIGA reactor.

Tue, 2 Oct 2007 00:00:00 +0000

Use of the RELAP5 thermal-hydraulic code to support the safety analysis for reactor power upgrade from 1.0 to 2.0 MW

Graphical user interfaces for the McCellan Nuclear Radiation Center (MNRC)

Tue, 2 Oct 2007 00:00:00 +0000

The McClellan’s Nuclear Radiation Center's control console is in the process of being replaced due to spurious scrams, outdated software, and obsolete parts; The intent of the new control is to eliminate the existing problems by installing a UNIX-based computer system with industry-standard interface software and incorporating human factors during all stages of the Graphical User Interface (GUI) development and control console design.

Neutron Tomography and Space

Mon, 1 Oct 2007 00:00:00 +0000

The University of California/Davis McClellan Nuclear Radiation Center (UCD/MNRC) was originally constructed by the U.S. Air Force as a nondestructive testing tool to detect moisture and corrosion in large honeycomb filled structures of aircrafts. The MNRC was transferred to UCD in February of 2000 as part of the Base Realignment and Closure (BRAC) process of McClellan Air Force Base. UCD MNRC has a sound base of research and industrial partnerships. Jet Propulsion Laboratory, Pasadena, CA. approached UCD MNRC with the need to image the condition of brushes contained in motors used in their space related projects. JPL explained that they were unable to see what they needed to see with X-rays. They wanted to know if we could see the carbon brushes in these motors. Using their samples, we initially performed two computed radiography (CR) shots 90 degrees apart through the diameter. Furthermore, another shot along the rotational axis was taken. The brushes could not be seen in...

Depletion calculations for the McClellan Nuclear Radiation Center.

Mon, 1 Oct 2007 00:00:00 +0000

Depletion calculations have been performed for the McClellan reactor history from January 1990 through August 1996. A database has been generated for continuing use by operations personnel which contains the isotopic inventory for all fuel elements and fuel-followed control rods maintained at McClellan. The calculations are based on the three-dimensional diffusion “theory code REBUS-3 which is available through the Radiation Safety Information Computational Center (RSICC). Burnup-dependent cross-sections were developed at zero power temperatures and full power temperatures using the WIMS “code (also available through RSICC). WIMS is based on discretized transport theory to calculate the neutron flux as a function of energy and position in a one-dimensional cell. Based on the initial depletion calculations, a method was developed to allow operations personnel to perform depletion calculations and update the database with a minimal amount of effort. Depletion estimates and calculations...

Optimization of neutron tomography for rapid hydrogen concentration inspection of metal castings

Fri, 28 Sep 2007 00:00:00 +0000

Hydrogen embrittlement describes a group of phenomena leading to the degradation of metal alloy properties. The hydrogen concentration in the alloy can be used as an indicator for the onset of embrittlement. A neutron tomography system has been optimized to perform nondestructive detection of hydrogen concentration in titanium aircraft engine compressor blades. Preprocessing of backprojection images and postprocessing of tomographic reconstructions are used to achieve hydrogen concentration sensitivity below 200 ppm weight. This paper emphasizes the postprocessing techniques which allow automated reporting of hydrogen concentration.

Using neutrons to fight forest fires

Thu, 27 Sep 2007 00:00:00 +0000

The University of California McClellan Nuclear Radiation Center was originally developed by the U.S. Air Force as a nondestructive testing tool to detect moisture and corrosion in large honeycomb filled surfaces of aircraft. MNRC was transferred to UCD in February of 2000 as part of the closure process of McClellan Force Base. UCD MNRC has a firm base of research and industrial partnerships. The United States Forest Service contracted Dyncorp Inc. to upgrade and perform safety checks fire fighting systems carried aboard Air National Guard C-130 aircraft. These fire fighting systems, "Modular Airborne Firefighting Systems", MAFFS, were fabricated in the early to mid 70’s. The tanks, tubing, and fittings that make up these systems are made of aluminum. They have been exposed to various fire retardant formulas. Following use, the systems are flushed with water and air dried. The result of these caustic and corrosive cycles was not known. Working through UC Davis' office of Technology...

Simple microscope using a compound refractive lens and a wide-bandwidth thermal neutron beam

Mon, 9 Apr 2007 00:00:00 +0000

The results of imaging experiments using biconcave, spherical compound refractive lenses (CRLs) and a wide-bandwidth thermal neutron beam are presented. Two CRLs were used, consisting of 155 beryllium and 120 copper lenses. The experiments were performed using a thermal neutron beam line at McClellan Nuclear Radiation Center reactor. The authors obtained micrographs of cadmium slits with up to 5× magnification and 0.3 mm resolution. The CRL resolution was superior to a pinhole camera with the same aperture diameter. The modulation transfer function (MTF) of the CRL was calculated and compared with the measured MTF at five spatial frequencies, showing good agreement. ©2007 American Institute of Physics

Fast Neutron Radioactivity and Damage Studies on Materials

Tue, 2 Jan 2007 00:00:00 +0000

Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) to improve reliability and longevity since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and gammas. Examples include NdFeB magnets, considered for the damping rings, injection and extraction lines and final focus, electronic and electro-optic devices to be utilized in detector readout, accelerator controls and the CCDs required for the vertex detector, as well as high and low temperature superconducting materials (LTSMs) because some magnets will be superconducting. Our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented for NdFeB materials at EPAC04 where the damage appeared proportional to the distances between the effective operating point and Hc. We have extended those doses, included other manufacturer's samples and measured induced radioactivities....

Application of Neutron-Absorbing Structural-Amorphous metal (SAM) Coatings for Spent Nuclear Fuel (SNF) Container to Enhance Criticality Safety Controls

Tue, 12 Dec 2006 00:00:00 +0000

Spent nuclear fuel contains fissionable materials (235U, 239Pu, 241Pu, etc.). To prevent nuclear criticality in spent fuel storage, transportation, and during disposal, neutron-absorbing materials (or neutron poisons, such as borated stainless steel, BoralTM, MetamicTM, Ni-Gd, and others) would have to be applied. The success in demonstrating that the High-Performance Corrosion- Resistant Material (HPCRM)1 can be thermally applied as coating onto base metal to provide for corrosion resistance for many naval applications raises the interest in applying the HPCRM to USDOE/OCRWM spent fuel management program. The fact that the HPCRM relies on the high content of boron to make the material amorphous – an essential property for corrosion resistance – and that the boron has to be homogenously distributed in the HPCRM qualify the material to be a neutron poison.

Non-Destructive Testing with Neutron Radiography at the UC Davis/ McClellan Nuclear Radiation Center

Thu, 7 Dec 2006 00:00:00 +0000

The UCD/ MNRC inherited NDT capabilities from the US Air Force and even though it is now mainly a research facility, it has kept this acquired asset performing at a production level. The UCD/MNRC facility is equipped with a hexagonal grid, natural convection water cooled TRIGA reactor designed to operate at a nominal 2 .0 MW steady state power as well as in pulse and square wave mode. The reactor utilizes a specially designed annular graphite reflector accommodating four removable units to accept four separate source ends of beam tubes. These tangential beam tubes lead to four large investigation bays with neutron radiography setting. The design basis for these beam tubes is to provide a path for primary thermal neutrons with minimum scattering and attenuation between the reflector inserts and radiography bays. Typical unperturbed beam parameters are summarized in the following: Each beam tube ends with a bulk shield as the primary beam stopper and...

Development of a Large-Field Cold Neutron Source at the University of California, Davis, McClellan Nuclear Radiation Center (UCD/ MNRC)

Thu, 7 Dec 2006 00:00:00 +0000

The project is to investigate, study, and develop a large-field, beryllium filtered cold neutron source for use in performing neutron radiography for a wide variety of basic research activities at the UC Davis/ McClellan Nuclear Radiation Center (MNRC). The UCD/ MNRC’s 2-MW TRIGA reactor which went online in 1990, and is the youngest research reactor in U.S. is renowned for its world-class facilities for performing thermal neutron radiography. It provides support for non-destructive inspection of materials and technology in the automotive, aerospace, and material science areas. The proposed research intends to study, design, modify, and transform one of the existing four thermal neutron radiography beams into a large-field, beryllium filtered cold neutron radiographic beam. When added to the extensive experiences in thermal neutron radiography, this additional capability will further enhance the existing thermal neutron radiography to support basic research activities in the...

Lidar characterization of crystalline silica generation and gravel plant

Thu, 7 Dec 2006 00:00:00 +0000

Light detection and ranging (Lidar) remote sensing two-dimensional vertical and horizontal scans collected downwind of a sand and gravel plant were used to evaluate the generation and transport of geologic fugitive dust emitted by quarry operations. The lidar data give unsurpassed spatial resolution of the emitted dust, but lack quantitative particulate matter (PM) mass concentration data. Estimates of the airborne PM10 and crystalline silica concentrations were determined using linear relationships between point monitor PM10 and quartz content data with the lidar backscatter signal collected from the point monitor location. Lidar vertical profiles at different distances downwind from the plant were used to quantify the PM10 and quartz horizontal fluxes at 2-m vertical resolution as well as off-site emission factors. Emission factors on the order of 65–110 kg of PM10 (10–30 kg quartz) per daily truck activity or 2–4 kg/t product shipped (0.5–1 kg quartz/t) were quantified for...

Radiation Hardness Testing of Materials at the UC Davis/ McClellan Nuclear Radiation Center

Thu, 7 Dec 2006 00:00:00 +0000

The UCD/ MNRC research reactor of the TRIGA type is designed to be operated at a nominal 2 .0 MW steady state power as well as pulse and square wave operation. It is cooled and moderated by light water and reflected by graphite. The reactor core is located near the bottom of a water-filled aluminum vessel 7.0 ft in diameter and 24.5 ft in height. It went first critical in 1990 and has since become the highest power TRIGA reactor in the U.S. Radiation hardness testing of materials is made possible through the so-called “neutron irradiator” which provides fast neutron exposure to samples with minimal contamination from thermal neutrons and gamma rays. This neutron irradiator has three primary components; conditioning well, exposure vessel, and detachable upper shield for the exposure vessel. The conditioning well is installed adjacent to the annular graphite reflector inside the reactor tank. It is held vertically in place and rests at the bottom of the tank. The well-structure...

Application of neutron computed tomography in the geosciences

Tue, 5 Dec 2006 00:00:00 +0000

A research program that applies neutron computed tomography (CT) to geological problems has been developed at the McClellan Nuclear Radiation Center (UCD-MNRC) owned and operated by the University of California, Davis (UCD-MNRC). The high penetration of neutrons, their sensitivity to light elements, and their special sensitivity to hydrogen (in water or organic materials) make them an ideal tool for non-destructive examination of complex materials of geological interest. There are four research foci at UCD-MNRC related to geological material characterization: (1) quantification of textures of deformed crystalline rocks; (2) properties of multi-phase flow in porous rocks and sediments; (3) distribution of organic and inorganic carbon in silicate and carbonate rocks; and (4) CO2 sequestration through fluid-rock reaction. Examples of these research activities will be presented. A new CT infrastructure is being installed at the UCD-MNRC to meet the needs of these four research...

Fast neutron Damage Studies on NdFeB Materials

Tue, 5 Dec 2006 00:00:00 +0000

Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and gamma’s over the life of the facility. While the linacs will be superconducting, there are still many uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the situation for rare earth, permanent magnet materials was presented at the Particle Accelerator Conference 2003. Our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at the European Particle Accelerator Conference 2004. We have extended the doses, included other manufacturer’s samples, and measured induced radioactivities which are discussed in detail.

Analytical Controlled Losses of Potassium from Straw

Tue, 5 Dec 2006 00:00:00 +0000

Accurate knowledge of the concentrations of potassium and other elements is critical for evaluating the effects of straw and other high-fouling biomass fuels in combustion boilers and other thermal systems. Development of accurate and precise analytical procedures is therefore essential for utilization of biomass fuels in energy production and high-temperature applications. By comparing the results of X-ray fluorescence (XRF) analyses with similar analyses done using instrumental neutron activation (INA), it is observed that 20-25% of the original K2O content of straw ashes and slag can be lost during sample preparation for analyses. The loss occurs during heating of the ashes to determine loss on ignition probably as a result of the breakdown of sylvite (KCl). This loss can be significantly reduced, but not completely eliminated, if the analyses are performed on ashes that have not previously been heat-treated. The study poses the cautionary note that similar losses may occur...

High temperature elemental losses and mineralogical

Tue, 5 Dec 2006 00:00:00 +0000

The elemental losses from ashes of common biomass fuels (rice straw, wheat straw, and wood) were determined as a function of temperature from 525 8C to below 1525 8C, within the respective melting intervals. The experimental procedure was chosen to approach equilibrium conditions in an oxidizing atmosphere for the specific ash and temperature conditions. All experiments were conducted in air and used the ashes produced initially at temperatures of 525 8C as reactants. Losses during the initial ashing at 525 8C were negligible, except for a K2O loss of 26% for wood and a Cl loss of 20% for wheat straw. Potassium losses are positively correlated with temperature for all fuel ashes. The K2O loss for wood ash commences at 900–1000 8C. Carbonate is detected in the wood ashes to about 700–800 8C and thus cannot explain the retention of K2O in the ashes to 1000 8C. Other crystalline phases detected in the wood ashes (pericline and larnite) contain little or no potassium. Petrographic...

Radiation Damage Studies with Hadrons on Materials and Electronics

Mon, 4 Dec 2006 00:00:00 +0000

Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, leptons and gamma’s over their life. Examples are NdFeB magnets considered for the damping rings and final focus, electronic and electro-optical devices to be utilized in detector readout and accelerator controls and CCDs required for the vertex detector. Effects of gamma’s on many materials have been presented and our understanding of the situation for rare earth permanent magnets at the Particle Accelerator Conference 2003. Here we give first measurements of the fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD/MNRC) together with the induced radioactivities. Damage appears to be proportional to the distances between the operating point and Hci.

Real-Time Neutron Radiography - Applications For The Automotive Industry

Fri, 1 Aug 2003 00:00:00 +0000

Real-Time Neutron Radiography - Applications For The Automotive Industry

Neutron tomography developments and applications

Fri, 1 Aug 2003 00:00:00 +0000

Neutron radiography has been in use as a nondestructive testing technique for the past fifty years. The neutrons’ unique ability to image certain elements and isotopes that are either completely undetectable or poorly detected by other NDI methods makes neutron radiography an important tool for the NDI community. Neutron radiography like other imaging techniques takes a number of different forms (i.e., film, radioscopic, transfer methods, tomography, etc.)

This paper will describe the neutron tomography system developed at the University of California, Davis McClellan Nuclear Radiation Center (UC Davis/MNRC), and the applications for both research and commercial uses.

The neutron radiography system at the UC Davis/MNRC has been under development for four years. The initial system was developed to find very low concentrations of hydrogen (i.e., < 200 ppm). In order to achieve these low detection levels, it was necessary to perform both pre- and post-processing...