The Hexagon, Volume 92, Number 4, Winter 2001

The Hexagon, Volume 92, Number 4, Winter 2001

Date: Winter 2001
Creator: Alpha Chi Sigma
Description: Quarterly publication of the Alpha Chi Sigma chemistry fraternity containing articles related to chemistry research and the activities of the organization, including local chapters and groups.
Contributing Partner: UNT Libraries
Biannual recalibration of two spectral gamma-ray logging systems used for baseline characterization measurements in the Hanford Tank Farms. Vadose Zone Characterization Project at the Hanford Tank Farms

Biannual recalibration of two spectral gamma-ray logging systems used for baseline characterization measurements in the Hanford Tank Farms. Vadose Zone Characterization Project at the Hanford Tank Farms

Date: May 1, 1996
Creator: Koizumi, C.J.
Description: The US Department of Energy`s (DOE`s) Grand Junction Projects Office (GJPO) is engaged in establishing an initial, or baseline, characterization of the gamma-ray-emitting contaminants in the subsurface of the Tank Farms at the DOE Hanford site in the State of Washington. These baseline data are gathered by logging existing monitoring boreholes with two high-resolution passive gamma-ray logging systems informally known as Gamma 1 and Gamma 2. Calibration of the logging systems is crucial to the assurance of data quality. The project document Spectral Gamma-Ray borehole Geophysical Logging Characterization and Baseline Monitoring Plan for the Hanford Single-Shell Tanks (DOE 1995a) specifies that the initial, or base, calibration of both systems must be performed before commencement of field measurements at Hanford and that both systems must be recalibrated every 6 months thereafter using the calibration standards at the Hanford borehole logging calibration center. Data collection for the base calibrations was completed in April 1995; the results were published in Calibration of Two Spectral Gamma-Ray Logging Systems for Baseline Characterization Measurements in the Hanford Tank Farms (DOE 1995b). This report documents the first recalibration of the two systems that was performed in October 1995 at the Hanford Site. Analyses of data collected during ...
Contributing Partner: UNT Libraries Government Documents Department
Rapid increase in prescission GDR {gamma}-ray emission with energy

Rapid increase in prescission GDR {gamma}-ray emission with energy

Date: December 31, 1995
Creator: Hofman, D.J.; Back, B.B. & Paul, P.
Description: A rapid increase in the emission of prescission giant dipole resonance (GDR) {gamma}-rays with bombarding energy is observed in excited Th and Cf nuclei formed in the reactions {sup 16}O+{sup 20B}Pb and {sup 32}S+{sup nat}W,{sup 208}Pb. This increase begins around E{sub exc} = 40 MeV for the {sup 16}O+{sup 208}Pb reaction and E{sub exc} = 70 MeV for the {sup 32}S-induced reactions. The excess {gamma}-ray yield above these thresholds cannot be described within the standard statistical model. Statistical model calculations which include a temperature dependent nuclear dissipation are able to reproduce simultaneously the observed GDR {gamma}-ray spectra and recently measured evaporation residue across sections.
Contributing Partner: UNT Libraries Government Documents Department
Derivation of guidelines for uranium residual radioactive material in soil at the Colonie Site, Colonie, New York

Derivation of guidelines for uranium residual radioactive material in soil at the Colonie Site, Colonie, New York

Date: May 1, 1996
Creator: Dunning, D.
Description: Residual radioactive material guidelines for uranium in soil were derived for the Colonie site located in Colonie, New York. This site has been designated for remedial action under the Formerly Utilized Sites Remedial Action Program (FUSRAP) of the U.S. Department of Energy (DOE). The site became contaminated with radioactive material as a result of operations conducted by National Lead (NL) Industries from 1958 to 1984; these activities included brass foundry operations, electroplating of metal products, machining of various components using depleted uranium, and limited work with small amounts of enriched uranium and thorium. The Colonie site comprises the former NL Industries property, now designated the Colonie Interim Storage Site (CISS), and 56 vicinity properties contaminated by fallout from airborne emissions; 53 of the vicinity properties were previously remediated between 1984 and 1988. In 1984, DOE accepted ownership of the CISS property from NL Industries. Residual radioactive material guidelines for individual radionuclides and total uranium were derived on the basis of the requirement that the 50-year committed effective dose equivalent to a hypothetical individual who lives or works in the immediate vicinity of the site should not exceed a dose of 30 mrem/yr following remedial action for the current use and ...
Contributing Partner: UNT Libraries Government Documents Department
Tentative method for the determination of plutonium-239 and plutonium-238 in water (by a coprecipitation anion exchange technique)

Tentative method for the determination of plutonium-239 and plutonium-238 in water (by a coprecipitation anion exchange technique)

Date: September 17, 1976
Creator: Bishop, C.T.; Brown, R.; Glosby, A.A.; Phillips, C.A. & Robinson, B.
Description: A procedure for the determination of plutonium 238 and plutonium 239 in water is described. The procedure consists of a coprecipitation, an anion exchange separation and electrodeposition, followed by alpha pulse height analysis. More specifically, the sample is acidified with nitric acid and plutonium-242 is added as a tracer before any chemical separations are performed. Iron is added to the water as iron (III) and the plutonium is coprecipitated with the iron as ferric hydroxide by adding ammonium hydroxide. After decantation and centrifugation, the ferric hydroxide precipitate containing the coprecipitated plutonium is dissolved and the solution is adjusted to 8M in HNO{sub 3} for anion exchange separation. When the sample fails to dissolve because of the presence of insoluble residue, the residue is treated by a rigorous acid dissolution using concentrated nitric acid and hydrofluoric acids. The sample is poured over an anion exchange column. The iron and most other elements that might be present pass through the column. Thorium is removed from the column with 12 M hydrochloric acid and then the plutonium is eluted by reducing it to plutonium (III) with the iodide ion. The plutonium is electrodeposited onto a stainless steel slide for counting by alpha pulse ...
Contributing Partner: UNT Libraries Government Documents Department
Neutron activation analysis of airborne thorium liberated during welding operations

Neutron activation analysis of airborne thorium liberated during welding operations

Date: February 1, 1996
Creator: Glasgow, D.C.; Robinson, L. & Janjovic, J.T.
Description: Typically, reactive metals such as aluminum are welded using a thoriated tungsten welding electrode which is attached to a source of argon gas such that the local atmosphere around the weld is inert. The metal is heated by the arc formed between the electrode and the grounded component to be welded. During this process, some of the electrode is vaporized in the arc and is potentially liberated to the surrounding air. This situation may result in a hazardous airborne thorium level. Because the electrode is consumed during welding, the electrode tip must be repeatedly dressed by grinding the tip to a fine point so that the optimal welding conditions are maintained. These grinding activities may also release thorium to the air. Data generated in the 1950s suggested that these electrodes posed no significant health hazard and seemed to justify their exemption from licensing requirements for source material. Since that time, other studies have been performed and present conflicting results as to the level of risk. Values both above and below the health protection limit in use in the United States, have been reported in the literature recently. This study is being undertaken to provide additional data which may be useful ...
Contributing Partner: UNT Libraries Government Documents Department
Completely automated nuclear reactors for long-term operation

Completely automated nuclear reactors for long-term operation

Date: January 1, 1996
Creator: Teller, E.; Ishikawa, M. & Wood, L.
Description: The authors discuss new types of nuclear fission reactors optimized for the generation of high-temperature heat for exceedingly safe, economic, and long-duration electricity production in large, long-lived central power stations. These reactors are quite different in design, implementation and operation from conventional light-water-cooled and -moderated reactors (LWRs) currently in widespread use, which were scaled-up from submarine nuclear propulsion reactors. They feature an inexpensive initial fuel loading which lasts the entire 30-year design life of the power-plant. The reactor contains a core comprised of a nuclear ignitor and a nuclear burn-wave propagating region comprised of natural thorium or uranium, a pressure shell for coolant transport purposes, and automatic emergency heat-dumping means to obviate concerns regarding loss-of-coolant accidents during the plant`s operational and post-operational life. These reactors are proposed to be situated in suitable environments at {approximately}100 meter depths underground, and their operation is completely automatic, with no moving parts and no human access during or after its operational lifetime, in order to avoid both error and misuse. The power plant`s heat engine and electrical generator subsystems are located above-ground.
Contributing Partner: UNT Libraries Government Documents Department
Weldon Spring Site Remedial Action Project approach to building dismantlement and demolition

Weldon Spring Site Remedial Action Project approach to building dismantlement and demolition

Date: January 1, 1996
Creator: Spittler, F.J.
Description: When remediation began at the Weldon Spring Site Remedial Action Project (WSSRAP), there were 41 buildings on site. Twenty-nine of these buildings were ancillary structures and were not used for processing radioactive material. Most of these have been torn down. The remaining 12 buildings were used for uranium and thorium processing or were major support structures, such as the laboratory. Two of the buildings were major processing operations occurred were successfully demolished in February of this year. Demolition of all structures will be complete in September of this year. To give an understanding of the magnitude of the work, the following is a description of the physical characteristics of the green salt building. This building was used to convert brown oxide (UO3) to green salt (UF4), which is the last intermediate step in purifying the mostly yellow cake feed material into uranium metal.
Contributing Partner: UNT Libraries Government Documents Department
Hanford Site background: Evaluation of existing soil radionuclide data

Hanford Site background: Evaluation of existing soil radionuclide data

Date: July 1, 1995
Creator: unknown
Description: This report is an evaluation of the existing data on radiological background for soils in the vicinity of the Hanford Site. The primary purpose of this report is to assess the adequacy of the existing data to serve as a radiological background baseline for use in environmental restoration and remediation activities at the Hanford Site. The soil background data compiled and evaluated in this report were collected by the Pacific Northwest Laboratory (PNL) and Washington State Department of Health (DOH) radiation surveillance programs in southeastern Washington. These two programs provide the largest well-documented, quantitative data sets available to evaluate background conditions at the Hanford Site. The data quality objectives (DQOs) considered in this evaluation include the amount of data, number of sampling localities, spatial coverage, number and types of radionuclides reported, frequency of reporting, documentation and traceability of sampling and laboratory methods used, and comparability between sets of data. Although other data on soil radionuclide abundances around the Hanford Site exist, they are generally limited in scope and lack the DQOs necessary for consideration with the PNL and DOH data sets. Collectively, these two sources provide data on the activities of 25 radionuclides and four other parameters (gross alpha, gross ...
Contributing Partner: UNT Libraries Government Documents Department
Variation of stability constants of thorium citrate complexes and of thorium hydrolysis constants with ionic strength

Variation of stability constants of thorium citrate complexes and of thorium hydrolysis constants with ionic strength

Date: September 1, 1995
Creator: Choppin, G.R.; Erten, H.N. & Xia, Y.X.
Description: Citrate is among the organic anions that are expected to be present in the wastes planned for deposition in the Waste Isolation Pilot Plant repository. In this study, a solvent extraction method has been used to measure the stability constants of Thorium(IV)[Th(IV)] with citrate anions in aqueous solutions with (a) NaClO{sub 4} and (b) NaCl as the background electrolytes. The ionic strengths were varied up to 5 m (NaCl) and 14 m (NaClO{sub 4}). The data from the NaClO{sub 4} solutions at varying pH values were used to calculate the hydrolysis constants for formation of Th(OH){sup 3+} at the different ionic strengths.
Contributing Partner: UNT Libraries Government Documents Department
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