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A device for the determination of low concentrations of oxygen in carbonaceous materials

Description: Oxygen in carbonaceous materials is converted to carbon monoxide (CO) by pyrolyzing the material in a stream of oxygen-free helium. The CO is reacted with Ni{sup 63}, a radioactive isotope of nickel, to form nickel tetracarbanyl (Ni{sup 63}(CO){sub 4}) which is carried by the helium stream into a flow-through gas proportional counter. The quantity of Ni(CO){sub 4} is determined by the radioactivity of the gas as measured by the gas proportional counter. After exiting the flow through counter the Ni{sub 63}(CO){sub 4} is destroyed by exposing it to high temperatures. The Ni{sub 63} is retained within the apparatus while the CO is flushed from the system after being oxidized to carbon dioxide (CO{sub 2}). The detection limit is estimated to be less than 1 part per billion oxygen for a 10 mg sample.
Date: December 31, 1991
Creator: Schultz, H.
Partner: UNT Libraries Government Documents Department

National Low-Level Waste Management Program Radionuclide Report Series. Volume 10, Nickel-63

Description: This report outlines the basic radiological, chemical, and physical characteristics of nickel-63 ({sup 63}Ni) and examines how these characteristics affect the behavior of {sup 63}Ni in various environmental media, such as soils, groundwater, plants, animals, the atmosphere, and the human body. Discussions also include methods of {sup 63}Ni production, waste types, and waste forms that contain {sup 63}Ni. The primary source of {sup 63}Ni in the environment has been low-level radioactive waste material generated as a result of neutron activation of stable {sup 62}Ni that is present in the structural components of nuclear reactor vessels. {sup 63}Ni enters the environment from the dismantling activities associated with nuclear reactor decommissioning. However, small amounts of {sup 63}Ni have been detected in the environment following the testing of thermonuclear weapons in the South Pacific. Concentrations as high as 2.7 Bq{sup a} per gram of sample (or equivalently 0.0022 parts per billion) were observed on Bikini Atoll (May 1954). {sup 63}Ni was not created as a fission product species (e.g., from {sup 235}U or {sup 239}Pu fissions), but instead was produced as a result of neutron capture in {sup 63}Ni, a common nickel isotope present in the stainless steel components of nuclear weapons (e.g., stainless-304 contains {approximately}9% total Ni or {approximately}0.3% {sup 63}Ni).
Date: February 1, 1995
Creator: Carboneau, M.L. & Adams, J.P.
Partner: UNT Libraries Government Documents Department

A decommissioning plan for the Heavy Water Components Test Reactor

Description: Three alternatives to decommission the Heavy Water Components Test Reactor (HWCTR) have been analyzed as summarized in Table 1. The protective confinement approach is advantageous as long as current activities onsite limit access by the general public; excellent confinement of the residual activity is provided by in situ dry storage as the radiation from {sup 60}Co diminishes. Entombment provides the most-secure confinement of the activity but at some increased cost. Dismantling HWCTR has no apparent advantages other than a demonstration at the Savannah River Plant site, because of the long-term commitment to safeguarding radioactive material; the relative cost is high. The induced radioactivity in HWCTR is current 2.3 {times} 10{sup 4} Ci; general area radiation levels are typically 3 mR/hr. In 35 years, the decay of {sup 60}Co will lower the radiation levels by a factor of 100, and the remaining radioactivity will be 2 {times} 10{sup 3} Ci of {sup 63}Ni. Minimal offsite effects are calculated to result after postulated structural failures to the decommissioned HWCTR facility. Flexibility and aesthetics favor dismantlement, but these criteria are considered less significant than public radiation dose, cost, and land area committed.
Date: January 1, 1976
Creator: Owen, M.B. & Field, F.R.
Partner: UNT Libraries Government Documents Department

Proof-of-concept development of PXAMS (projectile x-ray accelerator mass spectrometry)

Description: Prior to the current work, accelerator mass spectrometry (AMS) was limited to a set of {approximately}8--10 isotopes. This limitation is caused primarily by the inability to discriminate against stable atomic isobars. An analysis scheme that combines the isotopic sensitivity of AMS with similar isobar selectivity would open a large new class of isotope applications. This project was undertaken to explore the use of characteristic x rays as a method for the detection and identification of ions,and to allow the post-spectrometer rejection of isobaric interferences for isotopes previously inaccessible to AMS. During the second half of FY94 (with Advanced Concepts funding from the Office of Non-Proliferation and National Security), we examined the feasability of this technique, which we are referring to as PXAMS (Projectile X ray AMS), to the detection of several isotopes at Lawrence Livermore National Laboratory (LLNL). In our first exploratory work, we measured the x ray yield vs energy for {sup 80}Se ions stopped in a thick Y target. These results, demonstrated that useful detection efficiencies could be obtained for Se ions at energies accessible with our accelerator, and that the count rate from target x rays is small compared to the Se K{alpha} rate. We followed these measurements with a survey of x ray yields for Z = 14-46.
Date: March 1, 1996
Creator: Proctor, I.D.; Roberts, M.L.; McAninch, J.E. & Bench, G.S.
Partner: UNT Libraries Government Documents Department

Measurement of {sup 63}Ni and {sup 59}Ni by accelerator mass spectrometry using characteristic projectile x-rays

Description: The long-lived isotopes of nickel ({sup 59}Ni, {sup 63}Ni) have current and potential use in a number of applications including cosmic radiation studies, biomedical tracing, characterization of low-level radioactive wastes, and neutron dosimetry. Methods are being developed at LLNL for the routine detection of these isotopes by AMS. One intended application is in Hiroshima dosimetry. The reaction {sup 63}Cu(n,p){sup 63}Ni has been identified as one of a small number of reactions which might be used for the direct determination of the fast neutron fluence emitted by the Hiroshima bomb. AMS measurement of {sup 63}Ni(t{sub 1/2} = 100 y) requires the chemical removal of {sup 63}Cu, which is a stable isobar of {sup 63}Ni. Following the electrochemical separation of Ni from gram-sized copper samples, the Cu concentration is further lowered to < 2 x 10{sup -8} (Cu/Ni) using the reaction of Ni with carbon monoxide to form the gas Ni(CO){sub 4}. The Ni(CO){sub 4} is thermally decomposed directly in sample holders for measurement by AMS. After analysis in the AMS spectrometer, the ions are identified using characteristic projectile x-rays, allowing further rejection of remaining {sup 63}Cu. In a demonstration experiment, {sup 63}Ni was measured in Cu wires (2-20 g) which had been exposed to neutrons from a {sup 252}Cf source. We successfully measured {sup 63}Ni at levels necessary for the measurement of Cu samples exposed near the Hiroshima hypocenter. For the demonstration samples, the Cu content was chemically reduced by a factor of 10{sup 12} with quantitative retention of {sup 63}Ni. Detection sensitivity (3{sigma}) was {approximately}20 fg {sup 63}Ni in 1 mg Ni carrier ({sup 63}Ni/Ni {approx} 2 x 10{sup -11}). Significant improvements in sensitivity are expected with planned incremental changes in the methods. Preliminary results indicate that a similar sensitivity is achievable for {sup 59}Ni (t{sub 1/2} = 10{sup 5} ...
Date: May 1996
Creator: McAninch, J. E.; Hainsworth, L. J. & Marchetti, A. A.
Partner: UNT Libraries Government Documents Department

1992 Technical progress report of the University of South Carolina`s High Energy Physics Group

Description: The high energy physics group at the University of South Carolina includes five teaching faculty members, one research faculty member, and five graduate students. Professors Childers and Darden devote most of their research effort to Fermilab experiment E789, which is designed to observe charmless two-body decays of b-flavored mesons and baryons. Prof. Wilson works on E789 and also on Fermilab experiment E687 which studies charm physics in the wide-band photon beam. Professors Rosenfeld and Wang participate in the AMY collaboration, which studies electron-positron interactions using the TRISTAN collider at KEK. Prof. Rosenfeld and one student collaborate with personnel from KEK and INS, Tokyo, on an experiment to detect a 17 keV neutrino in the {beta}-decay spectrum of {sup 63}Ni. Profs. Avignone and Rosenfeld are charter members of Fermilab proposal P803, which will search for the oscillation of muon neutrino to tau neutrino with sensitivity better than a factor of 40 than previously achieved. A brief discussion on the progress of each program is given.
Date: December 31, 1992
Partner: UNT Libraries Government Documents Department

Radiological characterization of spent control rod assemblies

Description: This document represents the final report of an ongoing study to provide radiological characterizations, classifications, and assessments in support of the decommissioning of nuclear power stations. This report describes the results of non-destructive and laboratory radionuclide measurements, as well as waste classification assessments, of BWR and PWR spent control rod assemblies. The radionuclide inventories of these spent control rods were determined by three separate methodologies, including (1) direct assay techniques, (2) calculational techniques, and (3) by sampling and laboratory radiochemical analyses. For the BWR control rod blade (CRB) and PWR burnable poison rod assembly (BPRA), {sup 60}Co and {sup 63}Ni, present in the stainless steel cladding, were the most abundant neutron activation products. The most abundant radionuclide in the PWR rod cluster control assembly (RCCA) was {sup 108m}Ag (130 yr halflife) produced in the Ag-In-Cd alloy used as the neutron poison. This radionuclide will be the dominant contributor to the gamma dose rate for many hundreds of years. The results of the direct assay methods agree very well ({+-}10%) with the sampling/radiochemical measurements. The results of the calculational methods agreed fairly well with the empirical measurements for the BPRA, but often varied by a factor of 5 to 10 for the CRB and the RCCA assemblies. If concentration averaging and encapsulation, as allowed by 10CFR61.55, is performed, then each of the entire control assemblies would be classified as Class C low-level radioactive waste.
Date: October 1, 1995
Creator: Lepel, E.A.; Robertson, D.E.; Thomas, C.W.; Pratt, S.L. & Haggard, D.L.
Partner: UNT Libraries Government Documents Department

Prediction of stainless steel activation in experimental breeder reactor 2 (EBR-II) reflector and blanket subassemblies

Description: Stainless steel structural components in nuclear reactors become radioactive wastes when no longer useful. Prior to disposal, certain physical attributes must be analyzed. These attributes include structural integrity, chemical stability, and the radioactive material content among others. The focus of this work is the estimation of the radioactive material content of stainless steel wastes from a research reactor operated by Argonne National Laboratory.
Date: December 31, 1996
Creator: Bunde, K.A.
Partner: UNT Libraries Government Documents Department

Selected radionuclides important to low-level radioactive waste management

Description: The purpose of this document is to provide information to state representatives and developers of low level radioactive waste (LLW) management facilities about the radiological, chemical, and physical characteristics of selected radionuclides and their behavior in the environment. Extensive surveys of available literature provided information for this report. Certain radionuclides may contribute significantly to the dose estimated during a radiological performance assessment analysis of an LLW disposal facility. Among these are the radionuclides listed in Title 10 of the Code of Federal Regulations Part 61.55, Tables 1 and 2 (including alpha emitting transuranics with half-lives greater than 5 years). This report discusses these radionuclides and other radionuclides that may be significant during a radiological performance assessment analysis of an LLW disposal facility. This report not only includes essential information on each radionuclide, but also incorporates waste and disposal information on the radionuclide, and behavior of the radionuclide in the environment and in the human body. Radionuclides addressed in this document include technetium-99, carbon-14, iodine-129, tritium, cesium-137, strontium-90, nickel-59, plutonium-241, nickel-63, niobium-94, cobalt-60, curium -42, americium-241, uranium-238, and neptunium-237.
Date: November 1996
Partner: UNT Libraries Government Documents Department

The LLNL AMS facility

Description: The AMS facility at Lawrence Livermore National Laboratory (LLNL) routinely measures the isotopes {sup 3}H, {sup 7}Be, {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl, {sup 41}Ca, {sup 59,63}Ni, and {sup 129}I. During the past two years, over 30,000 research samples have been measured. Of these samples, approximately 30% were for {sup 14}C bioscience tracer studies, 45% were {sup 14}C samples for archaeology and the geosciences, and the other isotopes constitute the remaining 25%. During the past two years at LLNL, a significant amount of work has gone into the development of the Projectile X-ray AMS (PXAMS) technique. PXAMS uses induced characteristic x-rays to discriminate against competing atomic isobars. PXAMS has been most fully developed for {sup 63}Ni but shows promise for the measurement of several other long lived isotopes. During the past year LLNL has also conducted an {sup 129}I interlaboratory comparison exercise. Recent hardware changes at the LLNL AMS facility include the installation and testing of a new thermal emission ion source, a new multianode gas ionization detector for general AMS use, re-alignment of the vacuum tank of the first of the two magnets that make up the high energy spectrometer, and a new cryo-vacuum system for the AMS ion source. In addition, they have begun design studies and carried out tests for a new high-resolution injector and a new beamline for heavy element AMS.
Date: May 1996
Creator: Roberts, M. L.; Bench, G. S. & Brown, T. A.
Partner: UNT Libraries Government Documents Department

Tracer diffusion of /sup 60/Co and /sup 63/Ni in amorphous NiZr alloy

Description: Tracer diffusion of /sup 60/Co and /sup 63/Ni in equiatomic amorphous NiZr alloy in the temperature range between 486 and 641/sup 0/K can be described by: D/sub Co/sup */ = 3.7 x 10/sup -7/ exp(-(135 +- 14) kJ mole/sup -1//RT) m/sup 2//sec and D/sub Ni//sup */ = 1.7 x 10/sup -7/ exp(-(140 +- 9) kJ mole/sup -1//RT) m/sup 2//sec. The values of D/sub Ni//sup */ are in reasonable agreement with those measured by the Rutherford backscattering technique. The measured diffusivities were independent of time, indicating that no relaxation took place during diffusion. 27 refs., 2 tabs.
Date: January 1, 1987
Creator: Hoshino, K.; Averback, R.S.; Hahn, H. & Rothman, S.J.
Partner: UNT Libraries Government Documents Department

Grain-boundary diffusion: structural effects, models and mechanisms

Description: Grain boundary diffusion phenomena were considered including: anisotropy, effect of orientation, crystallographic transformation, boundary type, dislocation dissociation, pressure, and isotope effects. Diffusivity is different for various boundaries. Dissociated dislocations and stacking faults are not efficient paths for grain boundary diffusion. Results suggest a vacancy mechanism along the dislocation core, and involves atomic jumps away from the back towards the dislocation as well as jumps along the core. Measurements were made on nickel and silver. (FS)
Date: January 1, 1979
Creator: Peterson, N L
Partner: UNT Libraries Government Documents Department

Diffusion studies in amorphous NiZr alloys

Description: Tracer impurity and self diffusion measurements have been made on amorphous (a-) NiZr alloys using radioactive tracer, Secondary Ion Mass Spectrometry and Rutherford backscattering techniques. The temperature dependence of diffusion in a-NiZr can be represented in the form D = D/sub 0/exp(-Q/kT), with no structural relaxation effects being observed. The mobility of an atom in a-NiZr increased dramatically with decreasing atomic radius of the diffusing atom and also with decreasing Ni content for Ni concentrations below approx. =40 at. %. These diffusion characteristics in a-NiZr are remarkably similar to those in ..cap alpha..-Zr and ..cap alpha..-Ti. These mechanisms assume that Zr and Ti provide a close packed structure, either crystalline or amorphous, through which small atoms diffuse by an interstitial mechanism and large atoms diffuse by a vacancy mechanism. 12 refs., 2 figs., 2 tabs.
Date: June 1, 1987
Creator: Hahn, H.; Averback, R.S.; Hoshino, K. & Rothman, S.J.
Partner: UNT Libraries Government Documents Department

Plasma Separation Process: Betacell (BCELL) code: User's manual. [Bipolar barrier junction]

Description: The emergence of clearly defined applications for (small or large) amounts of long-life and reliable power sources has given the design and production of betavoltaic systems a new life. Moreover, because of the availability of the plasma separation program, (PSP) at TRW, it is now possible to separate the most desirable radioisotopes for betacell power generating devices. A computer code, named BCELL, has been developed to model the betavoltaic concept by utilizing the available up-to-date source/cell parameters. In this program, attempts have been made to determine the betacell energy device maximum efficiency, degradation due to the emitting source radiation and source/cell lifetime power reduction processes. Additionally, comparison is made between the Schottky and PN junction devices for betacell battery design purposes. Certain computer code runs have been made to determine the JV distribution function and the upper limit of the betacell generated power for specified energy sources. A Ni beta emitting radioisotope was used for the energy source and certain semiconductors were used for the converter subsystem of the betacell system. Some results for a Promethium source are also given here for comparison. 16 refs.
Date: November 13, 1987
Creator: Taherzadeh, M.
Partner: UNT Libraries Government Documents Department

Beta decay anomalies and the 17-keV conundrum

Description: Recent developments in pursuance of the 17-keV neutrino are reviewed. Several different experiments found anomalies in [beta] decay spectra which were consistently interpreted as evidence for a heavy neutrino. On the other hand, recent null results definitively rule out the existence of a 17-keV neutrino, as well as escaping criticisms applicable to earlier experiments. While missing links remain, it seems that any strong evidence for a 17-keV neutrino has vanished. Specifically, the anomalies observed in [sup 35]S and [sup 63]Ni spectra at Oxford can be reinterpreted in terms of electron scattering effects. In addition, the discrepancy amongst internal bremsstrahlung measurements has an instrumental origin, and recent results disfavour a 17-keV neutrino. Anomalies persist in the low energy region of the tritium spectrum which deserve further investigation.
Date: January 1, 1993
Creator: Hime, A.
Partner: UNT Libraries Government Documents Department

[Research programs from the University of South Carolina on High Energy Physics]. [119 Technical Progress Report]

Description: Work on three main experiments is summarized: (1) study of charm physics in a wide-band photon beam; (2) charmless two-body decays of b-flavored mesons and baryons studied with a ring imaging Cherenkov counter; and (3) the AMY Program, which studies e[sup +]e[sup [minus]] interactions using the TRISTAN collider at KEK, with emphasis on trigger upgrades. Future work related to the existence of a 17-keV neutrino in [beta] decay and [nu][sub [mu]]/[nu][sub [tau]] oscillation is described.
Date: January 1, 1993
Creator: Rosenfeld, C.
Partner: UNT Libraries Government Documents Department

Mechanisms of impurity diffusion in rutile

Description: Tracer diffusion of /sup 46/Sc, /sup 51/Cr, /sup 54/Mn, /sup 59/Fe, /sup 60/Co, /sup 63/Ni, and /sup 95/Zr, was measured as functions of crystal orientation, temperature, and oxygen partial pressure in rutile single crystals using the radioactive tracer sectioning technique. Compared to cation self-diffusion, divalent impurities (e.g., Co and Ni) diffuse extremely rapidly in TiO/sub 2/ and exhibit a large anisotropy in the diffusion behavior; divalent-impurity diffusion parallel to the c-axis is much larger than it is perpendicular to the c-axis. The diffusion of trivalent impurity ions (Sc and Cr) and tetravalent impurity ions (Zr) is similar to cation self-diffusion, as a function of temperature and of oxygen partial pressure. The divalent impurity ions Co and Ni apparently diffuse as interstitial ions along open channels parallel to the c-axis. The results suggest that Sc, Cr, and Zr ions diffuse by an interstitialcy mechanism involving the simultaneous and cooperative migration of tetravalent interstitial titanium ions and the tracer-impurity ions. Iron ions diffused both as divalent and as trivalent ions. 8 figures.
Date: January 1, 1984
Creator: Peterson, N.L. & Sasaki, J.
Partner: UNT Libraries Government Documents Department