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Basis for dose rate to curie assay method

Description: Disposition of low-level solid waste packages at the Hanford Site requires quantifying the radioactive contents of each container. This study generated conversion factors to apply to the results of contact surveys that are performed with standard dose rate survey instruments by field health physics technicians. This study determined the accuracy of this method, and identified the major sources of uncertainty. It is concluded that the dominant error is associated with the possibility that the radioactive source is not homogeneously distributed.
Date: October 31, 1996
Creator: Gedeon, S.R.
Partner: UNT Libraries Government Documents Department


Description: This report endeavors to point out the radiation hazards involved with respect to the patient undergoing oral roentgenography. The dose rate can be as high as 280 r/min. Very definite hematological changes have been observed and are being thoroughly investigated. Recommendations have been suggested to eliminate overexposures.
Date: July 16, 1952
Creator: Nolan, W. E.
Partner: UNT Libraries Government Documents Department

SATIF-2 shielding aspects of accelerators, targets and irradiation facilities

Description: Particle accelerators have evolved over the last 50 years from simple devices to powerful machines, and will continue to have an important impact on research, technology and lifestyle. Today they cover a wide range of applications, from television and computer displays in households to the investigation of the origin and structure of matter. It has become common practice to use them for material science and medical applications. In recent years, requirements from new technological and research applications have emerged, such as increased particle beams intensities, higher flexibility, etc., giving rise to new radiation shielding aspects and problems. These proceedings review recent progress in radiation shielding of accelerator facilities, and evaluate advancements with respect to international co-operation in this field.
Date: December 31, 1995
Partner: UNT Libraries Government Documents Department

Dose enhancement in a room cobalt-60 source

Description: A room Co-60 source was characterized using TLDs and pMOS RADFETs. Dose enhancement was measured using RADFETs with and without gold- flashed kovar lids. A methodology was developed to predict dose enhancement vs position and test configuration.
Date: June 1, 1997
Creator: Simons, M.; Pease, R.L.; Fleetwood, D.M.; Schwank, J.R. & Krzesniak, M.
Partner: UNT Libraries Government Documents Department

Inspection and Gamma-Ray Dose Rate Measurements of the Annulus of the VSC-17 Concrete Spent Nuclear Fuel Storage Cask

Description: The air cooling annulus of the Ventilated Storage Cask (VSC)-17 spent fuel storage cask was inspected using a Toshiba 7 mm (1/4”) CCD video camera. The dose rates observed in the annular space were measured to provide a reference for the activity to which the camera(s) being tested were being exposed. No gross degradation, pitting, or general corrosion was observed.
Date: September 1, 2007
Creator: Winston, P. L.
Partner: UNT Libraries Government Documents Department

Evaluation of Proposed New LLW Disposal Activity Disposal of No Dose/Low Dose Scrap Metal in Slit Trenches

Description: Activated metal is a special waste that requires evaluation for disposal. Contaminants in the activated metal will leach more slowly than will contaminants in generic waste. There is an inventory of activated scrap metal in the 105-L Disassembly Basin. Approximately 1,600 ft3 of the material is characterized as ''No Dose/Low Dose'' and consists mainly of activated aluminum and aluminum alloy pieces and parts and no stainless steel with a dose rate less than 200 mR per hr. Contaminants in the activated metal will leach more slowly than will contaminants in generic waste. The change in the leach rate will affect analyses for the groundwater pathway and intruder scenarios. For this evaluation, the slower leach rate from the activated metal waste will be neglected for the groundwater pathway, which is conservative because the higher leach rate used tends to produce higher groundwater concentrations and lower inventory limits. For this evaluation, the leach rate was set to zero for intruder scenarios, which is conservative for the inadvertent intruder because a slower leach rate will result in higher levels of radionuclides in the waste zone. The evaluation concludes that the existing limits are applicable to the disposal of No Dose/Low Dose activated scrap metal in slit trenches so that a Special Analysis is not needed to dispose of this waste stream.
Date: February 11, 2004
Creator: Cook, JR
Partner: UNT Libraries Government Documents Department

Diagnostic modeling for real-time emergency response

Description: The Atmospheric Release Advisory Capability (ARAC) provides real-time dose assessments for airborne pollutant releases. ARAC is currently in the process of developing an entirely new suite of models and system infrastructure. Diagnostic and dispersion algorithms are being created in-house and a prognostic model NO-RAPS, imported from the Naval Research Laboratory, Monterey, is currently being adapted to ARAC`s needs. Diagnostic models are essential for an emergency response capability since they provide the ability to rapidly assimilate available meteorological data and generate the mass-consistent three-dimensional wind fields required by dispersion models. The resulting wind fields may also serve to initialize and validate prognostic models. In general, the performance of diagnostic models strongly correlates with the density and distribution of measurements in the area of interest and the resolution of the terrain. problem, data can be extracted from user-specified databases within a region defined by a metdata grid. Typically the data collection region will cover a geographic domain significantly larger than the area involved in the dispersion simulation in order to provide the most complete set of meteorological information relevant to the problem. This also permits the user to redefine the problem grid size and location, within limits, without reaccessing the meteorological data extraction system. After the data has been collected, an associated meteorological preprocessor places it in a standard form for further processing. The pre-processor does not alter or interpolate wind values; it only performs reversible transformations to convert the data to a standard unambiguous form, e.g. latitude, longitude, height, wind speed and direction. This allows the diagnostic models to use a generalized data ingest routine, not dependent on the form or format of the meteorological data source or database.
Date: September 7, 1995
Creator: Sugiyama, G.; Rodriguez, D. & Lee, R.
Partner: UNT Libraries Government Documents Department

BUSFET - A Novel Radiation-Hardened SOI Transistor

Description: A partially-depleted SOI transistor structure has been designed that does not require the use of specially-processed hardened buried oxides for total-dose hardness and maintains the intrinsic SEU and dose rate hardness advantages of SOI technology.
Date: February 4, 1999
Creator: Dodd, P.E.; Draper, B.L.; Schwank, J.R. & Shaneyfelt, M.R.
Partner: UNT Libraries Government Documents Department

Radionuclide mass inventory, activity, decay heat, and dose rate parametric data for TRIGA spent nuclear fuels

Description: Parametric burnup calculations are performed to estimate radionuclide isotopic mass and activity concentrations for four different Training, Research, and Isotope General Atomics (TRIGA) nuclear reactor fuel element types: (1) Aluminum-clad standard, (2) Stainless Steel-clad standard, (3) High-enrichment Fuel Life Improvement Program (FLIP), and (4) Low-enrichment Fuel Life Improvement Program (FLIP-LEU-1). Parametric activity data are tabulated for 145 important radionuclides that can be used to generate gamma-ray emission source terms or provide mass quantity estimates as a function of decay time. Fuel element decay heats and dose rates are also presented parametrically as a function of burnup and decay time. Dose rates are given at the fuel element midplane for contact, 3.0-feet, and 3.0-meter detector locations in air. The data herein are estimates based on specially derived Beginning-of-Life (BOL) neutron cross sections using geometrically-explicit TRIGA reactor core models. The calculated parametric data should represent good estimates relative to actual values, although no experimental data were available for direct comparison and validation. However, because the cross sections were not updated as a function of burnup, the actinide concentrations may deviate from the actual values at the higher burnups.
Date: March 1, 1997
Creator: Sterbentz, J.W.
Partner: UNT Libraries Government Documents Department

Calculated dose rates in halls using CASIM

Description: The first part of this document shows the results of a series of CASIM runs designed to optimize the size of a steel cylinder so as to produce the highest density of stars at any given radius perpendicular to beam direction. For the next set of runs the length of the cylinder is now fixed at three meters and the authors vary the radius. These runs show that a cylinder with a radius of seven centimeters produces the highest dose rate. For the rest of the CASIM runs a cylinder three meters long with a radius of seven centimeters will be used. Using the optimized cylinder they now make runs using geometries more closely representing real experimental hall geometries in an attempt to predict possibly dose rates.
Date: February 1, 1995
Creator: Sondgeroth, A.
Partner: UNT Libraries Government Documents Department

Dose rate effects during damage accumulation in silicon

Description: We combine molecular dynamics and Monte Carlo simulations to study damage accumulation and dose rate effects during irradiation of Silicon. We obtain the initial stage of the damage produced by heavy and light ions using classical molecular dynamics simulations. While heavy ions like As or Pt induce amorphization by single ion impact, light ions like B only produce point defects or small clusters of defects. The amorphous pockets generated by heavy ions are stable below room temperature and recrystallize at temperatures below the threshold for recrystallization of a planar amorphous-crystalline interface. The damage accumulation during light ion irradiation is simulated using a Monte Carlo model for defect diffusion. In this approach, we study the damage in the lattice as a function of dose and dose rate. A strong reduction in the total number of defects left in the lattice is observed for lower dose rates.
Date: January 1, 1997
Creator: Caturla, M.J. & Diaz de la Rubia, T.
Partner: UNT Libraries Government Documents Department

Initial Results from an In-Vacuum Undulator in the NSLS X-ray Ring

Description: A short period, in vacuum undulator for the NSLS X-Ray Ring has been developed and has achieved its project design goals during commissioning studies. The device is called IVUN (In-Vacuum UNdulator) and employs magnet arrays (31 periods, with an 11 mm period) developed at SPring-8, while the requisite vacuum chamber and mechanical systems were developed at the NSLS. At a magnet gap of 3.3 mm, IVUN produces 4.6 keV radiation in the fundamental, with useful photon fluxes in both the 2nd and 3rd harmonics. The magnet gap is adjustable between 2 mm and 10 mm. A brief overview of IVUN is presented, together with initial commissioning results: the dependence of electron beam lifetime and bremsstrahlung on magnet gap, and the output radiation spectrum.
Date: November 1, 1997
Creator: Stefan, P.M.; Krinsky, S.; Rakowsky, G.; Solomon, L.; Tanabe, T. & Kitamura, H.
Partner: UNT Libraries Government Documents Department

Rate of long term bleaching in FK 51 optical glass darkened by Co60 ionizing radiation at dose rates of 10 krad/hr and 7 rad/hr

Description: A previous paper presented long term bleaching data on various glasses exposed to 10.6 krad of ionizing radiation. All the glasses reported except FK 51 have readily available `G` glass equivalents that are stabilized to the natural space environment. Yet, FK 51, because of its location on the Abbe diagram is extremely useful in certain lens design applications. To more fully explore the bleaching of FK 51, after the initial dose of 10.6 krad at 11.8 krad/hour, we irradiated three more samples at a similar dose rate but to different total doses. Since the dose rate for this study was significantly higher than the dose rate anticipated for glasses in as shielded space-based lens system (tilde 3 rad/day), additional data were obtained at a lower rate of 7 rad/hour. While this dose rate is still higher than the anticipated operational rate, it is more than 1000 times lower than the dose 011 011 011 rate used for our initial studies. The bleaching rate for the samples exposed at the lower dose rate is considerably less than for the samples exposed at the higher rate.
Date: July 1997
Creator: Wirtenson, G. R. & White, R. H.
Partner: UNT Libraries Government Documents Department

DOSFAC2 user`s guide

Description: This document describes the DOSFAC2 code, which is used for generating dose-to-source conversion factors for the MACCS2 code. DOSFAC2 is a revised and updated version of the DOSFAC code that was distributed with version 1.5.11 of the MACCS code. included are (1) an overview and background of DOSFAC2, (2) a summary of two new functional capabilities, and (3) a user`s guide. 20 refs., 5 tabs.
Date: December 1, 1997
Creator: Young, M.L. & Chanin, D.
Partner: UNT Libraries Government Documents Department

Cobalt source calibration

Description: The data obtained from these tests determine the dose rate of the two cobalt sources in SRTC. Building 774-A houses one of these sources while the other resides in room C-067 of Building 773-A. The data from this experiment shows the following: (1) The dose rate of the No.2 cobalt source in Building 774-A measured 1.073 x 10{sup 5} rad/h (June 17, 1999). The dose rate of the Shepherd Model 109 Gamma cobalt source in Building 773-A measured 9.27 x 10{sup 5} rad/h (June 25, 1999). These rates come from placing the graduated cylinder containing the dosimeter solution in the center of the irradiation chamber. (2) Two calibration tests in the 774-A source placed the graduated cylinder with the dosimeter solution approximately 1.5 inches off center in the axial direction. This movement of the sample reduced the measured dose rate 0.92% from 1.083 x 10{sup 5} rad/h to 1.073 x 10{sup 5} rad/h. and (3) A similar test in the cobalt source in 773-A placed the graduated cylinder approximately 2.0 inches off center in the axial direction. This change in position reduced the measured dose rate by 10.34% from 1.036 x 10{sup 6} to 9.27 x 10{sup 5}. This testing used chemical dosimetry to measure the dose rate of a radioactive source. In this method, one determines the dose by the chemical change that takes place in the dosimeter. For this calibration experiment, the author used a Fricke (ferrous ammonium sulfate) dosimeter. This solution works well for dose rates to 10{sup 7} rad/h. During irradiation of the Fricke dosimeter solution the Fe{sup 2+} ions ionize to Fe{sup 3+}. When this occurs, the solution acquires a slightly darker tint (not visible to the human eye). To determine the magnitude of the change in Fe ions, one places the solution in an ...
Date: December 3, 1999
Creator: Rizvi, H.M.
Partner: UNT Libraries Government Documents Department

Nevada Test Site annual site environmental report for calendar year 1998

Description: Prior to 1989, annual reports of environmental monitoring and assessment results for the Nevada Test Site (NTS) were prepared in two separate parts. Onsite effluent monitoring and environmental monitoring results were reported in an onsite report prepared by the US Department of Energy, Nevada Operations Office (DOE/NV). Results of the Offsite Radiological Surveillance and Long-Term Hydrological Monitoring Programs conducted by the US Environmental Protection Agency's (EPA) Laboratory (various names) in Las Vegas, Nevada, were reported separately by that Agency. Beginning with the 1989 Annual Site Environmental Report for the NTS, these two documents were combined into a single report to provide a more comprehensive annual documentation of the environmental protection activities conducted for the nuclear testing program and other nuclear and non-nuclear operations at the NTS. The two agencies have coordinated preparation of this tenth combined onsite and offsite report through sharing of information on environmental surveillance and releases as well as meteorological, hydrological, and other supporting data used in dose-estimation calculations.
Date: October 1, 1999
Creator: Black, S.C. & Townsend, Y.E.
Partner: UNT Libraries Government Documents Department


Description: Beam-induced radiation effects have been simulated for 20 and 50 GeV muon storage rings designed for a Neutrino Factory. It is shown that by appropriately shielding the superconducting magnets, quench stability, acceptable dynamic heat loads, and low residual dose rates can be achieved. Alternatively, if a specially-designed skew focusing magnet without superconducting coils on the magnet's mid-plane is used, then the energy is deposited preferentially in the warm iron yoke or outer cryostat layers and internal shielding may not be required. In addition to the component irradiation analysis, shielding studies have been performed. Calculations of the external radiation were done for both designs but the internal energy deposition calculations for the 20 GeV Study-2 lattice are still in progress.
Date: June 18, 2001
Partner: UNT Libraries Government Documents Department