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in subjects: "Americium 243"

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Prediction of the migration of several radionuclides in ocean sediment with the computer code IONMIG: a preliminary report

A computer code, IONMIG, which is used to calculate the far-field transport of radionuclides through ocean sediment by diffusion and convection is described. The code uses a two-dimensional, axisymmetric, explicit finite difference formulation. Preliminary results for several species (Cs, Pu, I, Tc) are given.

Date: May 1, 1980

Creator: Russo, A.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Total and spontaneous fission half-lives for americium and curium nuclides

The long-lived nuclides of the americium curium elements are of interest for their use in certain safeguard applications and for nuclear reactor burnup studies in waste management. Recommended values are presented for /sup 241,242m,243/Am, and for /sup 242,243,244,245,246,247,248,250/Cm. These values result from a consistent evaluation of all these half-lives. These preliminary estimates were presented earlier. The uncertainties are provided at the 95% confidence limit for each of the recommend… more

Date: January 1, 1985

Creator: Holden, Norman E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Transuranium Processing Plant semiannual report of production, status, and plans for period ending June 30, 1977

During the period January 1, 1977, through June 30, 1977, the following amounts of transuranium elements were recovered from 12 irradiated HFIR targets: 0.1g /sup 243/Am, 21g /sup 244/Cm, 29.5 mg /sup 249/Bk, 288 mg /sup 252/Cf, 1.48 mg /sup 253/Es, and 0.7 pg /sup 257/Fm. One batch of high-purity /sup 248/Cm (approximately 50 mg) was separated from /sup 252/Cf. Twenty-three shipments were made from TRU during the period; recipients and the amounts of nuclides are tabulated. Five HFIR targets, … more

Date: December 1, 1977

Creator: King, L. J.; Bigelow, J. E. & Collins, E. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Kilogram-scale purification of americium by ion exchange

Sequential anion and cation exchange processes have been used for the final purification of /sup 241/Am recovered during the reprocessing of aged plutonium metallurgical scrap. Plutonium was removed by absorption of Dowex 1, X-3.5 (30 to 50 mesh) anion exchange resin from 6.5 to 7.5 M HNO/sub 3/ feed solution. Following a water dilution to 0.75 to 1.0 M HNO/sub 3/, americium was absorbed on Dowex 50W, X-8 (50 to 100 mesh) cation exchange resion. Final purification was accomplished by elution of… more

Date: January 1, 1979

Creator: Wheelwright, E. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Burning nuclear wastes in fusion reactors

We have studied actinide burn-up in ICF reactor pellets; i.e., 14 MeV neutron fission of the very long-lived actinides that pose storage problems. A major advantage of pellet fuel region burn-up is safety: only milligrams of highly toxic and active material need to be present in the fusion chamber, whereas blanket burn-up requires the continued presence of tons of actinides in a small volume. The actinide data tables required for Monte Carlo calculations of the burn-up of /sup 241/Am and /sup 2… more

Date: February 20, 1980

Creator: Meldner, H.W. & Howard, W.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Americium and curium total half-lives and for the spontaneous fission branch

The long-lived nuclides of the americium and curium elements are of interest for their use in certain safeguard applications and for nuclear reactor burnup studies in waste management. Recommended values are presented for /sup 241,242m,243/Am, and for /sup 242,243,244,245,246,247,248,250/Cm. These values result from a consistent evaluation of all these half-lives. These preliminary estimates were presented earlier. The uncertainties are provided at the 95% confidence limit for each of the recom… more

Date: January 1, 1985

Creator: Holden, Norman E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The Isotopes of Americium

Three new americium activities (Am{sup 238}?, Am{sup 243}, and Am{sup 244?}, the latter two formed by n,{gamma} reactions) are described and some additional information is given on previously reported americium isotopes.

Date: April 11, 1950

Creator: Street, K.; Ghiroso, A. & Seaborg, G. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Airborne radioactive effluent study at the Savannah River Plant

Under the Clean Air Act, Sections 112 and 122 as amended in 1977, the Office of Radiation Programs (OPR) of the United States Environmental Protection Agency is currently developing standards for radionuclides emitted to the air by several source categories. In order to confirm source-term measurements and pathway calculations for radiation exposures to humans offsite, the ORP performs field studies at selected facilities that emit radionuclides. This report describes the field study conducted … more

Date: July 1, 1984

Creator: Blanchard, R.L.; Broadway, J.A.; Sensintaffar, E.L.; Kirk, W.P.; Kahn, B. & Garrett, A.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Transuranium processing plant report of production, status, and plans for the period January 1, 1978--September 30, 1978

During this period transuranium elements were obtained from 13 irradiated HFIR targets. The final purifications of three batches of /sup 248/Cm were completed. Forty-two product shipments were made from TRU. Six HFIR targets were fabricated; each contained approximately 2 g of /sup 243/Am and 7.5 g of cerium. The precision of the fast-neutron counting system in the TURF Californium Facility was improved sufficiently to permit assay of the /sup 252/Cf content in pellets, sources, and shipping pa… more

Date: June 1, 1979

Creator: King, L. J.; Bigelow, J. E. & Collins, E. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Cumulative releases of radionuclides from uncontained waste packages

This report describes mathematical predictions for the migration of radionuclides from an emplaced radioactive waste container. The model assumes a spherical-equivalent waste solid surrounded by backfill but neglects the effect of decay heat. 7 refs., 2 tabs. (TEM)

Date: July 1, 1986

Creator: Lee, W. W. L.; Kim, C. L.; Chambre, P. L. & Pigford, T. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Total and spontaneous fission half-lives of the americium and curium nuclides

The total half-life and the half-life for spontaneous fission are evaluated for the various long-lived nuclides of interest. Recommended values are presented for /sup 241/Am, /sup 242m/Am, /sup 243/Am, /sup 242/Cm, /sup 243/Cm, /sup 244/Cm, /sup 245/Cm, /sup 246/Cm, /sup 247/Cm, /sup 248/Cm, and /sup 250/Cm. The uncertainties are provided at the 95% confidence limit for each of the recommended values.

Date: January 1, 1984

Creator: Holden, Norman E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Separation of macro quantities of actinides by high-pressure cation exchange

Several kilograms of /sup 244/Cm and /sup 243/Am and several milligrams of /sup 252/Cf were produced by irradiation of a mixture of plutonium isotopes. The plutonium was separated by solvent extraction, and the other actinides were separted from each other and from large quantities of fission-product rare earths by displacement-development chromatography in a system of pressurized steel columns in high level caves. The elutriant was 0.05 M DTPA buffered with ammonium hydroxide. Part of one of t… more

Date: January 1, 1979

Creator: Burney, G. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Transuranium processing plant semiannual report of production, status, and plans for period ending December 31, 1977

Transuranium elements were obtained from 13 irradiated HFIR targets. One batch of high-purity /sup 248/Cm (approximately 75 mg) was separated from /sup 252/Cf. Eighteen shipments were made from TRU during the period. Seven HFIR targets, each containing 8 to 9 g of curium, were fabricated. A new scrubber system was installed in the dissolver off-gas (DOG) stream to remove the bulk of the /sup 131/I and to reduce the amount sorbed in the Hopcalite--charcoal system. During TRU target Campaign 53, … more

Date: August 1, 1978

Creator: King, L. J.; Bigelow, J. E. & Collins, E. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Solubility of AmOHCO sub 3 in aqueous solution under atmospheric conditions

Modeling calculations on the solubility of americium have indicated that basic americium carbonate, and not americium trihydroxide, is the solubility-controlling solid in the pH range from 6 to 10 under the influence of atmospheric CO{sub 2}. The solubility of crystalline {sup 243}AmOHCO{sup 3} has been investigated in batch experiments in near-neutral and basic solutions as a function of dissolution time in 0.1 M NaClO{sup 4} at room temperature under oxic conditions. After the solutions reach… more

Date: December 1, 1987

Creator: Nitsche, H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Actinide cross section data and inertial confinement fusion for long term waste disposal

Actinide cross section data at thermonuclear neutron energies are needed for the calculation of ICF pellet center burnup of fission reactor waste, viz. 14 MeV neutron fission of the very long-lived actinides that pose storage problems. A major advantage of pellet center burnup is safety: only milligrams of highly toxic and active material need to be present in the fusion chamber, whereas blanket burnup requires the continued presence of tons of actinides in a small volume. The actinide data tab… more

Date: January 15, 1979

Creator: Meldner, Heiner

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Review of measurement techniques for stack monitoring of long-lived alpha emitters

As a result of the promulgation of new guidelines by the Environmental Protection Agency (40 CFR 190) for releases of long-lived, alpha-emitting substances, the stack-monitoring requirements for measuring long-lived alpha particles may change in terms of both monitored isotopes and the detection levels. This paper briefly reviews stack-monitoring requirements for long-lived alpha-emitting particles. It also examines the currently deployed alpha-particulate, stack-monitoring systems and discusse… more

Date: November 1, 1978

Creator: Kordas, J. F. & Phelps, P. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Techniques of preparation and crystal chemistry of transuranic chalcogenides and pnictides

The crystal chemistry of a number of transuranic chalcogenides and pnictides has been investigated using /sup 243/Am, /sup 248/Cm, /sup 249/Bk, and /sup 249/Cf. These compounds were prepared from the corresponding metals by direct reaction with the chalcogen or pnictogen element at elevated temperatures. Higher chalcogenides were thermally dissociated to yield ones of lower stoichiometry, terminating with the sesquichalcogenides; only monopnictides of these transplutonium elements were found. A… more

Date: January 1, 1978

Creator: Damien, D.A.; Haire, R.G. & Peterson, J.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Preparation and characterization of radioactive samples for various areas of research

Over the past few years, many techniques have been applied by IRML to prepare radioisotope targets and related research materials from actinide and other radioisotopes. Many of these samples were prepared by ceramic technology--an R and D program extending over the past three years. Standard vapor deposition methods have been used to prepare hundreds of fission chamber and other planar samples used in determining cross sections. Refined methods of characterization of all samples have been appli… more

Date: January 1, 1978

Creator: Adair, H.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Recent accomplishments in low-level radioactive waste measurement at Los Alamos

Is Los Alamos National Laboratory (LANL) the only laboratory that has difficulty measuring low concentrations of alpha radioactivity in wastewater, or do the rest of the nation`s laboratories just not realize the lack of precision/accuracy in its own measurements? DOE Order 5400.5 sets 30 pCi/L total alpha as a goal for effluent discharge. The State of Colorado requires 0.05 pCi/L. The EPA is considering standards in this range for drinking water and therefore, presumably in treated wastewater … more

Date: March 1, 1994

Creator: Midkiff, W. S.; Attrep, M. & Covey, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Proposal for experiments with actinide elements

An analytical study was conducted in which critical masses for some actinide isotopes were calculated with the Monte Carlo Neutron Photon (MCNP) Transport computer code. Different spherical computer models were used for even- and odd-neutron nuclides. Critical masses obtained are tabulated for Np-237, Pu-242, Am-241, Am-243, Pu-241, and Am-242m, together with indirect experimental data. Experimental data are needed for actinides with odd number of neutrons.

Date: June 1, 1994

Creator: Sanchez, R. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Evaluation of low-level waste analysis using the MADAM system

Previously, the important hardware features and capabilities for the Multiple Assay Dual Analysis Measurement (MADAM) system were reported. MADAM is a combined low-level and transuranic waste assay system. The system integrated commercially available Segmented Gamma Scanner (SGS) capability together with multienergy X-ray and gamma-ray analysis to measure these two waste forms. In addition, the system incorporated a small neutron slab detector to satisfy safeguards concerns and high resolution … more

Date: August 1, 1994

Creator: Foster, L. A.; Wachter, J. R. & Hagan, R. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Estimation of Ni{sup 63}, Pu{sup 241}, Pu{sup 242} and Am{sup 243} from Co{sup 60}, Pu{sup 239}, and Cm{sup 244} activities in groundwater samples

The Part B Permit for F&H Seepage Basins calls for analysis of several constituents of concern in groundwater monitoring wells. Four of these analytes are the radionuclides Ni{sup 63}, Pu{sup 241}, Pu{sup 242}, and Am{sup 243}. These are currently not being analyzed due to their very difficult, tedious analytical schemes coupled with their relatively low activity values. This report demonstrates how the activity value for Ni{sup 63}, a week beta emitter, can be estimated from that of Co{sup 60}… more

Date: May 14, 1993

Creator: Holcomb, H. P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Solubility of AmOHCO{sub 3} in aqueous solution under atmospheric conditions

Date: December 1, 1987

Creator: Nitsche, H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Fission Cross Section Calculations of Actinides With EMPIRE Code

The cross sections of the neutron induced reactions on {sup 233,234,236}U, {sup 237}Np, {sup 238,242}Pu, {sup 241,243}Am, {sup 242,246}Cm carried out in the energy range 1 keV-20 MeV with EMPIRE code are presented, emphasizing the fission channel. Beside a consistent, accurate set of evaluations, the paper contains arguments supporting the choice of the reaction models and input parameters. A special attention is paid to the fission parameters and their uncertainties.

Date: April 30, 2010

Creator: Sin, M.; Oblozinsky, P.; Herman,M. & Capote,R.

Item Type: Report

Partner: UNT Libraries Government Documents Department