The Importance of Transuranium Solids in Solubility Studies for Nuclear Waste Repositories

1991 ◽  
Vol 257 ◽  
Author(s):  
Heino Nitsche
Keyword(s):  
Nuclear Waste ◽  
Yucca Mountain ◽  
Mountain Region ◽  
Solubility Study ◽  
J 13 ◽  
Groundwater Systems ◽  
Solubility Studies ◽  
Waste Repositories

ABSTRACTSolids obtained from laboratory solubility experiments in two different groundwaters from the Yucca Mountain region, Nevada, are described. The solubility study provided limiting solubility concentrations for neptunium(V), plutonium(IV), and americium(III) in groundwaters from Wells J-13 and UE-25p#l. The solubility-controlling solids are compared to relevant radionuclide compounds that are reported in the literature. The preparations and some characteristics of published solids that possibly may form in actinide-groundwater systems are described. The solids formed in the experiments are sodium neptunium(V) carbonates, polymeric Pu(IV) that contained small amounts of carbonate, and hexagonal or orthorhombic americium(III) hydroxycarbonates.

scholarly journals Radiogeological Assessment of Candidate Sites For Nuclear Waste Repositories, Exemplified by Studies of The Stripa Pluton, Sweden

1981 ◽  
Vol 6 ◽  
Author(s):  
H. A. Wollenberg ◽  
S. Flexser ◽  
L. Andersson
Keyword(s):  
Nuclear Waste ◽  
Radioactive Decay ◽  
Apparent Size ◽  
Geothermal Heat ◽  
Flow Paths ◽  
Naturally Occurring ◽  
Groundwater Systems ◽  
Natural Tracer ◽  
Waste Repositories ◽  
Potassium 40

ABSTRACTInvestigation of candidate sites for nuclear waste isolation will require an assessment of their radiogeologic settings. Studies at the Stripa research facility in granitic rock of central Sweden incorporated the distribution and abundance of naturally occurring radioelements in rocks encompassing the underground experiments and in the accompanying fracture-controlled groundwater system. These studies showed that besides defining the natural radioactivity baseline upon which the effects of radioactive waste will be superimposed, radioelement distributions can be used to determine the apparent age of the groundwater and its flow paths. In crystalline rocks, where the groundwater systems are confined to the joints and fractures, the uranium daughter element, radon-222 in the water serves as a natural tracer to locate fractures along which significant flow is occurring and to measure the flow rates. The heat production from radioactive decay of uranium-238, thorium-232 and potassium-40 in the rock, combined with measurements of regional and local geothermal heat flow, permit calculation of the apparent size of the rock mass that will encompass the repository. This method is especially useful in terranes such as at Stripa where the contacts between plutons and older rocks are concealed.

Changes of Selected Structural and Mechanical Properties of the Strzelin Granites As Induced By Thermal Loads / Wpływ Obciążeń Termicznych Na Zmiany Niektórych Strukturalnych I Mechanicznych Właściwości Granitów Strzelińskich

2012 ◽  
Vol 57 (4) ◽  
pp. 951-974 ◽  
Author(s):  
Andrzej Nowakowski ◽  
Mariusz Młynarczuk
Keyword(s):  
Mechanical Properties ◽  
Nuclear Waste ◽  
Structural Changes ◽  
Structural Parameters ◽  
Total Porosity ◽  
Fracture Network ◽  
Qualitative Description ◽  
Temperature Changes ◽  
Heating And Cooling ◽  
Waste Repositories

Abstract Temperature is one of the basic factors influencing physical and structural properties of rocks. A quantitative and qualitative description of this influence becomes essential in underground construction and, in particular, in the construction of various underground storage facilities, including nuclear waste repositories. The present paper discusses the effects of temperature changes on selected mechanical and structural parameters of the Strzelin granites. Its authors focused on analyzing the changes of granite properties that accompany rapid temperature changes, for temperatures lower than 573ºC, which is the value at which the β - α phase transition in quartz occurs. Some of the criteria for selecting the temperature range were the results of measurements carried out at nuclear waste repositories. It was demonstrated that, as a result of the adopted procedure of heating and cooling of samples, the examined rock starts to reveal measurable structural changes, which, in turn, induces vital changes of its selected mechanical properties. In particular, it was shown that one of the quantities describing the structure of the rock - namely, the fracture network - grew significantly. As a consequence, vital changes could be observed in the following physical quantities characterizing the rock: primary wave velocity (vp), permeability coefficient (k), total porosity (n) and fracture porosity (η), limit of compressive strength (Rσ1) and the accompanying deformation (Rε1), Young’s modulus (E), and Poisson’s ratio (ν).

Experimental study and modeling of uranium (VI) transport through ferrous olivine rock columns

2000 ◽  
Vol 88 (9-11) ◽  
Author(s):  
M. Rovira ◽  
F.Z. El Aamrani ◽  
L. Duro ◽  
Ignasi Casas ◽  
Joan de Pablo ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Reactive Transport ◽  
Calculated Data ◽  
Buffering Capacity ◽  
Retardation Factor ◽  
Reactive Transport Modeling ◽  
Redox Active ◽  
Different Types ◽  
Free Media ◽  
Waste Repositories

The Lovasjärvi intrusion (SE-Finland) contents a high percentage of ferrous olivine (> 65%). This material has been suggested as a redox-active backfill-additive in deep nuclear waste repositories, due to the large Fe(II) proportion in its mineral composition. In order to understand the processes involved in the redox buffering capacity of this material the transport of uranium (VI) through olivine columns was studied. The results showed considerable retardation factor for the U(VI), particularly in carbonate-free media. The experimental data were simulated by means of reactive transport modeling. The best agreement between the experimental and calculated data was obtained considering that the interaction of U(VI) with the olivine surface occurred at two different types of sorption sites. One type accounts for the sorption capacity of the olivine mineral, and a second type accounts for the sorption on amorphous Fe(OH)

Experimental Investigation of Hydrous Pyrolysis of Diesel Fuel and the Effect of Pyrolysis Products on Performance of the Candidate Nuclear Waste Repository at Yucca Mountain

1993 ◽  
Vol 333 ◽  
Author(s):  
Kenneth J. Jackson ◽  
Susan A. Carroll
Keyword(s):  
Experimental Investigation ◽  
Nuclear Waste ◽  
Diesel Fuel ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Hydrothermal Solutions ◽  
Pyrolysis Products ◽  
Analytical Technique ◽  
Hydrous Pyrolysis ◽  
Waste Repository

It is thought that a significant amount of diesel fuel and other hydrocarbon-rich phases may remain inside the candidate nuclear waste repository at Yucca Mountain after construction and subsequent emplacement of radioactive waste. Although the proposed repository horizon is above the water table, the remnant hydrocarbon phases may react with hydrothermal solutions generated by high temperature conditions that will prevail for a period of time in the repository. The preliminary experimental results of this study show that diesel fuel hydrous pyrolysis is minimal at 200°C and 70 bars. The composition of the diesel fuel remained constant throughout the experiment and the concentration of carboxylic acids in the aqueous phases was only slightly above the detection limit (1–2 ppm) of the analytical technique.

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