scholarly journals Facile incorporation of technetium into magnetite, magnesioferrite, and hematite by formation of ferrous nitrate in situ: precursors to iron oxide nuclear waste forms

2018 ◽  
Vol 47 (30) ◽  
pp. 10229-10239 ◽  
Author(s):  
Wayne W. Lukens ◽  
Sarah A. Saslow
Keyword(s):  
Iron Oxide ◽  
Fission Product ◽  
Nuclear Waste ◽  
Half Life ◽  
Fission Yield ◽  
Waste Forms ◽  
Nuclear Waste Forms

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.

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 ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Chemical Properties ◽  
Electronic Charge ◽  
Chemical Information ◽  
Waste Forms ◽  
Charge States ◽  
Physical And Chemical ◽  
Nuclear Waste Forms

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.

A Flow Model for the Kinetics of Dissolution of Nuclear Waste Forms; A Comparison of Borosilicate Glass, Synroc and High-Silica Glass

1981 ◽  
Vol 11 ◽  
Author(s):  
Pedro B. Macedo ◽  
Aaron Barkatt ◽  
Joseoph H. Simmons
Keyword(s):  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Flow Model ◽  
Release Rates ◽  
Waste Forms ◽  
High Silica ◽  
Kinetics Of Dissolution ◽  
Kinetics Of ◽  
Nuclear Waste Forms

A model has been developed to predict the long-term leach or release rates of various waste-form materials under repository conditions.

The Long-Term Performance of Nuclear Waste Forms: Natural Materials - Three Case Studies

1992 ◽  
Vol 294 ◽  
Author(s):  
Rodney C. Ewing
Keyword(s):  
Case Studies ◽  
Nuclear Waste ◽  
Experimental Results ◽  
Waste Form ◽  
Short Term ◽  
Waste Forms ◽  
Long Term Performance ◽  
Term Performance ◽  
Nuclear Waste Forms

ABSTRACTNatural materials may be used to advantage in the evaluation of the long-term performance of nuclear waste forms. Three case studies are presented: (I) radiation effects in ceramic waste forms; (II) corrosion products of U02 under oxic conditions; (III) corrosion rate of nuclear waste glasses. For each case, a natural phase which is structurally and chemically analogous to the waste form is identified and used to evaluate the long-term behavior of a nuclear waste form. Short-term experimental results are compared to the observations made of analogous natural phases. The three case studies illustrate that results may range between providing fundamental data needed for the long-term evaluation of a waste form to only providing qualitative data of limited use. Although in the most rigorous view the long-term behaviour of a phase cannot be predicted, the correspondence between short-term experimental results and observations made of natural phases provides confidence in the “predicted” behavior of the waste form. The strength of this approach rests with the degree to which a mechanistic understanding of the phenomenon is attained.

Response of Zircon to Electron and Ne+ Irradiation

1997 ◽  
Vol 481 ◽  
Author(s):  
R. Devanathan ◽  
W. J. Weber ◽  
L. A. Boatner
Keyword(s):  
Nuclear Waste ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Voltage Electron ◽  
Waste Forms ◽  
High Voltage Electron Microscope ◽  
Ion Accelerator ◽  
Order Of Magnitude ◽  
Nuclear Waste Forms

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.

Ion Implantation Damage in Silicate Glasses

1982 ◽  
Vol 15 ◽  
Author(s):  
George W. Arnold
Keyword(s):  
Ion Implantation ◽  
Nuclear Waste ◽  
Silicate Glasses ◽  
Glass Waste ◽  
Leach Rate ◽  
Implantation Damage ◽  
Waste Forms ◽  
Long Term Behavior ◽  
Nuclear Waste Forms

ABSTRACTIon implantation is a rapid technique for simulating damage induced by α-recoil nuclei in nuclear waste forms. The simulation has been found to be quite good in TEM comparisons with natural α-decay damage in minerals, but leach rate differences have been observed in glass studies and were attributed to dose-rate differences. The similarities between ion implantation and recoil nuclei as a means of producing damage suggest that insights into the long-term behavior of glass waste forms can be obtained by examination of what is known about ion-implantation damage in silicate glasses. This paper briefly reviews these effects and shows that leaching results in certain nuclear waste glasses can be understood as resulting from plastic flow and track overlap. Phase separation is also seen to be a possible consequence of damage-induced compositional changes.

Results from a One-Year Leach Test: Long-Term Use of Mcc-L

1981 ◽  
Vol 11 ◽  
Author(s):  
D. M. Strachan
Keyword(s):  
Pacific Northwest ◽  
Nuclear Waste ◽  
Chemical Properties ◽  
Materials Characterization ◽  
Performance Measurements ◽  
Waste Forms ◽  
One Year ◽  
Nuclear Waste Forms ◽  
And Chemical Properties

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).

scholarly journals Ab Initio Investigation of Helium Mobility in La2Zr2O7 Pyrochlore

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Yanxia Lu ◽  
Qing Peng ◽  
Chenguang Liu
Keyword(s):  
Nuclear Waste ◽  
Density Functional ◽  
Minimum Energy ◽  
Elastic Band ◽  
Waste Forms ◽  
Band Method ◽  
And Migration ◽  
High Level ◽  
Migration Pathways ◽  
Nuclear Waste Forms

The α-decay of incorporated actinides continuously produces helium, resulting in helium accumulation and causing security concerns for nuclear waste forms. The helium mobility is a key issue affecting the accumulation and kinetics of helium. The energy barriers and migration pathways of helium in a potential high-level nuclear waste forms, La2Zr2O7 pyrochlore, have been investigated in this work using the climbing image nudged elastic band method with density functional theory. The minimum energy pathway for helium to migrate in La2Zr2O7 is identified as via La–La interstitial sites with a barrier of 0.46 eV. This work may offer a theoretical foundation for further prospective studies of nuclear waste forms.

Sign in / Sign up

Export Citation Format

Share Document