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Isotopes of Neptunium and Plutonium

Description: This report describes work done that originated in an effort to identify previously unknown isotopes of neptunium and plutonium and to characterize a few that were known for extension of the nuclear energy surface. The findings of this work results in two new light plutonium isotopes and one heavy neptunium isotope that were produced by bombardment of uranium with helium and deuteron ions from a 60-inch cyclotron and a 184-inch cyclotron. The chemical and experimental methods are described as well as the results of the bombardment work for each nuclide.
Date: December 1950
Creator: Orth, Donald Alfred
Partner: UNT Libraries Government Documents Department

Soft Radiation From Pu²³⁹

Description: "The radiation from Pu²³⁹ have been studied in the region 5-25 keV. For this purpose, a proportional counter, filled with argon to a pressure of 53 cm Hg and with methane to a pressure of 6 cm Hg, was employed in combination with a single-channel pulse analyzer and associated amplifying and counting circuits."
Date: 1952
Creator: Israel, Harvey Ira
Partner: UNT Libraries Government Documents Department

Radiation of Pu²⁴³

Description: "The radiations of Pu²⁴³ were studied with beta and gamma scintillation spectrometers alone and in coincidence. An incomplete disintegration scheme is deduced which leads to a total beta disintegration energy of 560 kev. A half-life of 4.98 ± 0.02 hours was observed."
Date: October 1952
Creator: Engelkemeir, D. W.; Fields, Paul R. & Huizenga, John R.
Partner: UNT Libraries Government Documents Department

The [beta]-Spectra of Pu²³⁹, Pu²⁴⁰, Pu²⁴¹and Sm¹⁵¹

Description: The [beta] spectrum of the 10-year Pu²⁴¹ was run on a sample of radiochemically pure plutonium containing the isotopes Pu²³⁹, Pu²⁴⁰, Pu²⁴¹, isotopically enriched in Pu²⁴¹ by pile neutron irradiation. The isotopic composition was determined mass spectrographically.
Date: February 8, 1952
Creator: Wagner, F.; Freedman, Melvin S. & Engelkemeir, D. W.
Partner: UNT Libraries Government Documents Department

Spontaneous Fission of 48

Description: Report discussing an experiment to reinvestigate the spontaneous fission of 48 (Pu-238) in an effort to determine a more accurate value for the spontaneous fission constant that was found in a previous experiment.
Date: December 19, 1949
Creator: Jungerman, John A.
Partner: UNT Libraries Government Documents Department

Proceedings of the NEANDC/NEACRP Specialists Meeting on Fast Neutron Fission Cross Sections of U-233, U-235, U-238, and Pu-239

Description: This supplement to the Proceedings of the NEANDC/NEACRP Specialists Meeting on Fast Fission Cross Sections summarizes the data and graphical material presented for consideration by the Working Groups on absolute cross section values and cross section ratios.
Date: 1976
Creator: Poenitz, W. P. & Guenther, P. T.
Partner: UNT Libraries Government Documents Department


Description: A new rapid fusion method for the determination of plutonium in large rice samples has been developed at the Savannah River National Laboratory (Aiken, SC, USA) that can be used to determine very low levels of plutonium isotopes in rice. The recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid, reliable radiochemical analyses for radionuclides in environmental and food samples. Public concern regarding foods, particularly foods such as rice in Japan, highlights the need for analytical techniques that will allow very large sample aliquots of rice to be used for analysis so that very low levels of plutonium isotopes may be detected. The new method to determine plutonium isotopes in large rice samples utilizes a furnace ashing step, a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a column separation process with TEVA Resin� cartridges. The method can be applied to rice sample aliquots as large as 5 kg. Plutonium isotopes can be determined using alpha spectrometry or inductively-coupled plasma mass spectrometry (ICP-MS). The method showed high chemical recoveries and effective removal of interferences. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory plutonium particles are effectively digested. The MDA for a 5 kg rice sample using alpha spectrometry is 7E-5 mBq g{sup -1}. The method can easily be adapted for use by ICP-MS to allow detection of plutonium isotopic ratios.
Date: March 1, 2013
Creator: Maxwell, S.
Partner: UNT Libraries Government Documents Department

Determination of Americium

Description: The following report describes a successful procedure used for the determination of americium in the presence of plutonium. Provided are articles listed that describe the research done in developing the method.
Date: October 15, 1952
Creator: Schmidt, H. R.
Partner: UNT Libraries Government Documents Department

Proceedings of the NEANDC/NEACRP Specialists Meeting on Fast Neutron Fission Cross Sections of U-233, U-235, U-238, and Pu-239, June 28-30, 1976, at Argonne National Laboratory

Description: Compilation of papers presented during the meeting of NEANDC/NEACRP specialists to discuss fast neutron fission cross sections of U-233, U-235, U-238, and Pu-239.
Date: 1976?
Creator: Poenitz, W. P. & Smith, A. B.
Partner: UNT Libraries Government Documents Department

A Portable Calorimeter System for Nondestructive Assay of Mixed-Oxide Fuels

Description: Calorimetric assay provides a precise, nondestructive method to determine sample plutonium content based on the heat emitted by decaying radionuclides. This measurement, in combination with a gamma-spectrometer analysis of sample isotopic content, yields the total sample plutonium mass. The technique is applicable to sealed containers and is essentially independent of sample matrix configuration and elemental composition. Conventional calorimeter designs employ large water-bath heat sinks and lack the portability needed by inspection personnel. The ANL air-chamber isothermal calorimeters are low-thermal-capacitance devices which eliminate the need for large constant-temperature heat sinks. These instruments are designed to use a feedback system that applies power to maintain the sample chamber at a constant electrical resistance and, therefore, at a constant temperature. The applied-power difference between a plutonium-containing sample and a blank determines the radioactive-decay power. The operating characteristics of a calorimeter designed for assaying mixed-oxide powders, fuel pellets, and plutonium-containing solutions are discussed. This device consists of the calorimeter, sample pre-heater, and a microprocessor-controlled data-acquisition system. The small-sample device weighs 18 kg and has a measurement cycle of 20 min, with a precision of 0.1% at 10 mW. A 100-min gamma-ray measurement gives the specific power with a precision of better than 1% for samples containing 1 to 2 g of plutonium.
Date: 1978
Creator: Roche, C. T.; Perry, R. B.; Lewis, R. N.; Jung, E. A. & Haumann, J. R.
Partner: UNT Libraries Government Documents Department

Selection of Actinide Chemical Analogues for WIPP Tests: Potential Nonradioactive Sorbing and Nonsorbing Tracers for Study of Ion Transport in the Environment

Description: Chemical characteristics of the actinides (Th, U, Np, Pu, Am) have been studied relative to nonradioactive chemical elements that have similar characteristics in an attempt to identify a group of actinide chemical analogues that are nonradioactive. In general, the chemistries of the actinides, especially U, Np, Pu, and Am, are very complex and attempts to identify a single chemical analogue for each oxidation state were not successful. However, the rationale for selecting a group of chemical analogues that would mimic the actinides as a group is provided. The categorization of possible chemical analogues (tracers) with similar chemical properties was based on the following criteria. Categorization was studied according.
Date: August 1, 1998
Creator: Spall, Dale & Villarreal, Robert
Partner: UNT Libraries Government Documents Department


Description: The theory and results of chemical exchange experiments for separation of Pu and U isotopes are presented. Solvent extraction systems were studied in both aqueous and organic media. Chemical exchange systems are proposed which could yield high separation factors. (W.L.H.)
Date: May 16, 1955
Creator: Hahn, H.T.
Partner: UNT Libraries Government Documents Department

Status of Current Plutonium Evaluations And an Update Plan for ENDL99

Description: We review the current state of ENDL99, ENDF/B-VI.r8, JENDL-3.3, JEFF-3.0 and ENDF/B-VII.{beta}0 plutonium evaluations and lay out a tentative plan for updating all of the ENDL99 plutonium evaluations. In some specific cases, an evaluation for a particular isotope is of sufficient quality for us to adopt in ENDL99. More often, the quality of all evaluations for an isotope are low enough that we will need to perform a new evaluation.
Date: April 29, 2005
Creator: Brown, D A
Partner: UNT Libraries Government Documents Department

Radionuclide Concentrations in Soils and Vegetation at Low-Level Radioactive Waste Disposal Area G during the 1997 Growing Season

Description: Soil and overstory and understory vegetation (washed and unwashed) collected at eight locations within and around Area G-a low-level radioactive solid-waste disposal facility at Los Alamos National Laboratory-were analyzed for 3H, 238Pu, 239Pu, 137CS, 234U, 235U, 228AC, Be, 214Bi, 60Co, 40& 54Mn, 22Na, 214Pb and 208Tl. In general, most radionuclide concentrations, with the exception of 3Ef and ~9Pu, in soils and overstory and understory vegetation collected from within and around Area G were within upper (95'%) level background concentrations. Although 3H concentrations in vegetation from most sites were significantly higher than background (>2 pCi mL-l), concentrations decreased markedly in comparison to last year's results. The highest `H concentration in vegetation was detected from a juniper tree that was growing over tritium shaft /+150; it contained 530,000 pCi 3H mL-l. Also, as in the pas~ the transuranic waste pad area contained the highest levels of 239Pu in soils and in understory vegetation as compared to other areas at Area G.
Date: August 1, 1998
Creator: L. Naranjo, Jr.; Fresquez, P. R. & Wechsler, R. J.
Partner: UNT Libraries Government Documents Department

Time and frequency domain measurements for plutonium metal rings

Description: The {sup 252}Cf-source-driven noise analysis method was used to measure the neutron multiplication factor for subcritical systems and to identify fissionable materials and configurations. These measurements with the moderator-ring configuration have shown that the {sup 252}Cf-source-driven noise methods, both in the time and frequency domain, can be used to identify and distinguish the {sup 242}Pu from the {sup 239}Pu ring. Signatures for each ring can be used to track and confirm the presence of these two types of Pu rings. Because of the sensitivity of these signatures to mass, these measurements can also confirm the Pu mass. These preliminary measurements have not yet explored the full range of capability of this method for this application.
Date: September 1996
Creator: Mihalczo, J. T.; Pare, V. K.; Blakeman, E. D.; Valentine, T. E.; Vessard, S. & Pruvost, N. L.
Partner: UNT Libraries Government Documents Department