scholarly journals Decontamination of process waste solutions containing fission products by adsorption and co-precipitation methods

1951 ◽  
Author(s):  
C. S. Lowe ◽  
R. L. Bates ◽  
L. L. Bentz ◽  
G. W. Frink ◽  
M. McEwen ◽  
...  
Keyword(s):  
Fission Products ◽  
Process Waste ◽  
Co Precipitation

Separation of Lanthanide Fission Products in a Eutectic Waste Salts Delivered From Pyroprocessing of a Spent Oxide Fuel by Using Lab-Scale Oxidative Precipitation Apparatus

2009 ◽  
Author(s):  
Yung-Zun Cho ◽  
In-Tae Kim ◽  
Hee-Chul Yang ◽  
Hwan-Seo Park ◽  
Han-Soo Lee
Keyword(s):  
Molten Salt ◽  
Fission Products ◽  
Oxide Fuel ◽  
Lanthanide Oxides ◽  
Lanthanide Elements ◽  
Oxidative Precipitation ◽  
Co Precipitation ◽  
Oxidation Efficiency

Co-precipitation experiments of lanthanides were carried out using this lab-scale apparatus (4kg-salt/batch). As lanthanides, 8 lanthanide elements (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) were used. By reaction with oxygen, these 8 lanthanide chlorides were converted their oxide (REO2, RE2O3) or oxychloride form. Since these lanthanide oxides or oxychlorides are nearly molten salt insoluble, they all were precipitated by free settling in the bottom of molten salt bed, where about 7–8 hrs precipitation time was requested. It was found that in the conditions of 700 °C - 12 hours sparging time and 5 L/min, all the used lanthanide elements showed over 99.5% oxidation efficiency. But in case of 800 °C molten salt temperature only after 7 hours they showed over 99% oxidation efficiency.

HLW-Glass Dissolution and Co-Precipitation Studies

2006 ◽  
Vol 932 ◽  
Author(s):  
Berthold Luckscheiter ◽  
Maria Nesovic
Keyword(s):  
Fission Products ◽  
Solution Concentration ◽  
Solubility Data ◽  
Soluble Form ◽  
Glass Dissolution ◽  
Glass Corrosion ◽  
Alkaline Earths ◽  
Solid Phases ◽  
Co Precipitation

ABSTRACTTo determine the maximum attainable solution concentrations of U, Th and fission products during long-term glass corrosion, co-precipitation studies were performed. The HLW-glass GPWAK 1 was dissolved in highly acid and basic media (100 g glass/L) at 80°C and by preparing acid solutions containing the various elements in soluble form. After dissolution the pH of the solution was slowly lowered/increased and the high concentrated solutions become super-saturated and strong precipitation takes place. The found pH-dependent concentrations of the various elements reflect their different solubility, lowest concentration for Th, Zr and Fe and highest for B, alkalis and alkaline earths. To find out the solid phases controlling the solution concentration, the run of the concentrations of some elements is compared with the solubility data of their pure solid phases (e.g. hydroxides) from literature. It was found that the concentrations of Nd, Th and U in dependence on pH agree quite well with solubility data of AmOHCO3, ThO2/Th(OH)4 and Schoepite UO2·(OH)2) ·H2O. Therefore, it can be assumed that the maximum attainable concentrations of many elements are controlled by such pure solid phases.

Nuclear Processes Related to the Ap Stars and the Heaviest Chemical Elements

1976 ◽  
Vol 32 ◽  
pp. 169-182
Author(s):  
B. Kuchowicz
Keyword(s):  
Nuclear Physics ◽  
Nuclear Reactions ◽  
Chemical Elements ◽  
Fission Products ◽  
Abundance Pattern ◽  
Isotopic Shifts ◽  
Processed Material ◽  
R Process ◽  
Ap Stars ◽  
Nuclear Processes

SummaryIsotopic shifts in the lines of the heavy elements in Ap stars, and the characteristic abundance pattern of these elements point to the fact that we are observing mainly the products of rapid neutron capture. The peculiar A stars may be treated as the show windows for the products of a recent r-process in their neighbourhood. This process can be located either in Supernovae exploding in a binary system in which the present Ap stars were secondaries, or in Supernovae exploding in young clusters. Secondary processes, e.g. spontaneous fission or nuclear reactions with highly abundant fission products, may occur further with the r-processed material in the surface of the Ap stars. The role of these stars to the theory of nucleosynthesis and to nuclear physics is emphasized.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

TEM studies of amorphization processes and amorphous structures

1988 ◽  
Vol 46 ◽  
pp. 448-449
Author(s):  
T. E. Mitchell ◽  
R. B. Schwarz
Keyword(s):  
Amorphous Materials ◽  
Fission Products ◽  
Rapid Quenching ◽  
Surface Films ◽  
List Type ◽  
Oxide Glasses ◽  
Crystalline Materials ◽  
Amorphous Structures ◽  
Amorphous Surface ◽  
Interfacial Films

Traditional oxide glasses occur naturally as obsidian and can be made easily by suitable cooling histories. In the past 30 years, a variety of techniques have been discovered which amorphize normally crystalline materials such as metals. These include [1-3]:Rapid quenching from the vapor phase.Rapid quenching from the liquid phase.Electrodeposition of certain alloys, e.g. Fe-P.Oxidation of crystals to produce amorphous surface oxide layers.Interdiffusion of two pure crystalline metals.Hydrogen-induced vitrification of an intermetal1ic.Mechanical alloying and ball-milling of intermetal lie compounds.Irradiation processes of all kinds using ions, electrons, neutrons, and fission products.We offer here some general comments on the use of TEM to study these materials and give some particular examples of such studies.Thin specimens can be prepared from bulk homogeneous materials in the usual way. Most often, however, amorphous materials are in the form of surface films or interfacial films with different chemistry from the substrates.

Pre-concentration of selected trace elements from seawater by co-precipitation on Mg(OH)2

2003 ◽  
Vol 107 ◽  
pp. 945-948 ◽  
Author(s):  
P. M. Nicolaysen ◽  
E. Steinnes ◽  
T. E. Sjobakk
Keyword(s):  
Trace Elements ◽  
Co Precipitation

Fission Products Release from Irradiated FBR MOX Fuel during Transient Conditions.

2003 ◽  
Vol 40 (2) ◽  
pp. 104-113 ◽  
Author(s):  
Isamu SATO ◽  
Toshio NAKAGIRI ◽  
Takashi HIROSAWA ◽  
Sinya MIYAHARA ◽  
Takashi NAMEKAWA
Keyword(s):  
Fission Products ◽  
Transient Conditions ◽  
Mox Fuel
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