The Application of 57FE Mössbauer Spectroscopy to the Characterization of Nuclear Waste Forms

1981 ◽  
Vol 6 ◽  
Author(s):  
Paul G. Huray ◽  
M. T. Spaar ◽  
S. E. Nave ◽  
J. M. Legan ◽  
L. A. Boatner ◽  
...  

The electronic charge states and site symmetries of the radioactive ions incorporated in nuclear waste forms are of considerable importance in determining the physical and chemical properties of these materials. An in situ characterization of these ions is, unfortunately, often difficult – especially when a mixture of charge states and local crystal symmetries exist. The application of Mbssbauer spectroscopy represents a powerful technique for obtaining solid state chemical information.

2018 ◽  
Vol 47 (30) ◽  
pp. 10229-10239 ◽  
Author(s):  
Wayne W. Lukens ◽  
Sarah A. Saslow

The fission product, 99Tc, presents significant challenges to the long-term disposal of nuclear waste due to its long half-life, high fission yield, and to the environmental mobility of pertechnetate (TcO4−), the stable Tc species in aerobic environments.


1999 ◽  
Vol 576 ◽  
Author(s):  
L. Balogh ◽  
K. S. Laverdure ◽  
S. P. Gido ◽  
A. G. Mott ◽  
M. J. Miller ◽  
...  

ABSTRACTDendrimer metal nanocomposites are novel hybride materials that display unique physical and chemical properties as a consequence of the atomic/molecular level dispersion of inorganic and organic molecules. In their synthesis, dendrimers are used as templates to pre-organize metal ions followed by an in-situ reduction, which will immobilize and stabilize atomic domains of the reaction product(s). Size, shape, size distribution and surface functionality of these nanocomposites are determined and controlled by the dendritic macromolecules and may also be influenced by the encapsulated compounds. Solubility of these molecular nanocomposites is controlled by the polymer. Thus, it is possible to solubilize conventionally insoluble inorganic compounds in water or other solvents using dendritic hosts. Conceptually, these materials have enormous potential for applications such as catalysts or molecular devices.In this work, surface-modified poly(amido-amine) dendrimers were used to prepare {Cu(0)-PAMAM}, {Ag(0)-PAMAM} and {Au(0)-PAMAM} dendrimer-metal nanocomposites containing stable and solvent soluble zero valence metals. Characterization of the resulting nanocomposites has been carried out by TEM, UV-visible spectroscopy, and scattering techniques. Depending on the chemistry of ion preorganization in the dendrimer, internal (“I”), external (“E”) and mixed (“M”) type nanocomposite structures could be identified according to the varying location of the actual metal content.The effect of structural differences was found to be reflected in the optical properties of the nanocomposites.


1994 ◽  
Vol 353 ◽  
Author(s):  
William J. Weber ◽  
Rodney C. Ewing

AbstractSite restoration activities at DOE facilities and the permanent disposal of nuclear waste generated at the same DOE facilities involve working with and within various types and levels of radiation fields. Radionuclide decay and the associated radiation fields lead to physical and chemical changes that can degrade or enhance material properties. This paper reviews the impact of radiation fields on site restoration activities and on the release rate of radionuclides to the biosphere from nuclear waste forms.


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 7893-7905
Author(s):  
Qianqian Zhu ◽  
Jingjing Wang ◽  
Jianzhong Sun ◽  
Qianqian Wang

The application of cellulose hybrid biocomposites filled with calcium carbonate has attracted wide attention in packaging and other fields in recent years. In this study, regenerated cellulose (RC) films filled with calcium carbonate were successfully prepared by dissolution, regeneration, and in situ precipitation of CaCO3. The optical, mechanical, physical, and chemical properties of biocomposites were examined by UV-visible spectroscopy, tensile testing, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analyses (TGA). The results showed that RC films with different CaCO3 contents exhibited good flexibility, optical properties, mechanical strength, and thermal stability. The RC biocomposite filled with calcium carbonate showed a tensile strength of 84.7 ± 1.5 MPa at optimum conditions. These RC biocomposites filled with CaCO3 may find application in packaging.


1997 ◽  
Vol 481 ◽  
Author(s):  
R. Devanathan ◽  
W. J. Weber ◽  
L. A. Boatner

ABSTRACTZircon (ZrSiO4) is an actinide host phase in vitreous ceramic nuclear waste forms and a potential host phase for the disposition of excess weapons plutonium. In the present work, the effects of 800 and 900 keV electron, and 1 MeV Ne+ irradiations on the structure of single crystals of ZrSiO4 have been investigated. The microstructural evolution during the irradiations was studied in situ using a high-voltage electron microscope interfaced to an ion accelerator at Argonne National Laboratory. The results indicate that electron irradiation at 15 K cannot amorphize ZrSiO4 even at fluences an order of magnitude higher than that required for amorphization by 1.5 MeV Kr + ions. However, the material is readily amorphized by I MeV Ne+ irradiation at 15 K. The temperature dependence of this amorphization is discussed in light of previous studies of radiation Zdamage in ZrSiO4.


1981 ◽  
Vol 11 ◽  
Author(s):  
D. M. Strachan

The Nuclear Waste Materials Characterization Center at Pacific Northwest Laboratory is developing standard tests to obtain data on nuclear waste forms, barriers, and backfills. These tests include performance measurements of thermal, radiation, mechanical, and chemical properties. Five tests have been developed to determine the chemical durability of waste forms under either static (MCC-IP and MCC-2P) or flowing (MCC-4S and MCC-5S) leaching environments. Maximum credible release by waste forms is determined using powders and stirred solutions (MCC-3S).


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