A New Approach to the Selection of Materials for Engineered Barriers and Appropriate Host Rocks for High Level Waste Disposal

1994 ◽  
Vol 353 ◽  
Author(s):  
B.I. Omelianenko ◽  
B.S. Nikonov ◽  
B.I. Ryzhov ◽  
N.D. Shikina ◽  
S.V. Yudintsev
Keyword(s):  
Volcanic Rocks ◽  
High Level Waste ◽  
Sorptive Capacity ◽  
Basaltic Rocks ◽  
Distribution Study ◽  
Deep Wells ◽  
Basic Volcanic ◽  
High Level ◽  
Host Rocks ◽  
Basic Rocks

AbstractSorptive properties of weathered dunites, gabbro-diabases and basic volcanic rocks for Sr and Cs were studied. The results show that the sorptive capacities of these rocks are equivalent to or, in some cases, superior to industrial sorptive materials. Results of a uranium distribution study by fission-track radiography suggest that material from weathered basic rocks is characterized by high sorptive properties for uranium also. One can assume that other radionuclides of the transuranic group will be intensely sor-bed by the residuum of weathered basic rocks. Low-temperature hyd-rothermal transformation leads to sealing fissures of the basic rocks with highly sorptive minerals, for example, smectite, chlorite, serpentine, talc, zeolite, hydroxides of Fe, Ti, Mn. The process results in contemporaneous decreasing hydraulic conductivity and increasing sorptive capacity of the rocks. HLW disposal at the radiochemical plant “Mayak” is expected to be produced in deep wells situated in basaltic rocks. The safety of disposal is based on high sorptive properties of the crust of weathering and protective capacities of volcanic rocks. This method is not expensive and may allow the disposal of HLW in the near future.

Density determinations of basic volcanic rocks of the Yellowknife supergroup by gravity measurements in mine shafts—Yellowknife, Northwest Territories

Geophysics ◽  
1980 ◽  
Vol 45 (1) ◽  
pp. 18-31 ◽  
Author(s):  
R. A. Gibb ◽  
M. D. Thomas
Keyword(s):  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Mine Shaft ◽  
Average Interval ◽  
Basaltic Rocks ◽  
Surface Samples ◽  
Gravity Measurements ◽  
Vertical Density ◽  
Basic Volcanic

Gravity measurements were made in two gold mine shafts sunk in the Archean Yellowknife greenstone belt to determine the in‐situ densities of basic volcanic rocks of the Kam formation, Yellowknife supergroup. Thirteen stations were occupied between the surface and a depth of 608 m at an average interval of about 50 m in the C shaft of Giant Yellowknife Mines Limited, and 14 stations were occupied between the surface and a depth of 1598 m at an average interval of about 120 m in the Robertson shaft of Con mine, Cominco Limited. Densities were computed using the terminology of borehole gravimetry with appropriate corrections for surface terrain and underground voids such as shafts, drifts, and stopes. Weighted mean in‐situ densities of [Formula: see text] (36 to 608 m depth) and [Formula: see text] (surface to 1598 m depth) were obtained from the gravity measurements for the Giant and Robertson sections, respectively; these values compare with mean densities of 2.82 and [Formula: see text] obtained from rock samples collected at the underground gravity stations. Sheared specimens and massive specimens collected at both underground and surface gravity stations have mean densities of 2.80 and [Formula: see text], respectively. Unaltered surface samples collected at stratigraphic intervals of about 150 m throughout the entire volcanic sequence have a mean density of [Formula: see text]. Core samples obtained from holes drilled from the bottom of C shaft extend the vertical density profile for the Giant section from a depth of 608 to 1416 m; the mean density of these samples is [Formula: see text]. The lower bulk densities obtained from the mine shaft experiments reflect in part the high proportion of sheared rocks and in part the presence of lower‐density members of the Kam formation (andesite, dacite, tuff, breccia, and agglomerate) in the vicinity of the shafts, as opposed to purely massive basaltic rocks. A density of [Formula: see text] based on the proportion of low‐ and high‐density rocks in the volcanic belt is considered to be more representative of the Kam formation as a whole.

scholarly journals Preliminary modelling of radionuclide migration in the argillaceous sediments of the Sumer Formation (Northwestern Bulgaria)

2020 ◽  
Vol 49 (3) ◽  
pp. 13-18
Author(s):  
Dimitar Antonov ◽  
Madlena Tsvetkova ◽  
Doncho Karastanev
Keyword(s):  
Radioactive Waste Disposal ◽  
High Level Waste ◽  
Spent Fuel ◽  
Radionuclide Migration ◽  
Geological Disposal ◽  
Disposal Facility ◽  
Deep Geological Disposal ◽  
High Level ◽  
Host Rocks ◽  
Selection Of

In Bulgaria, from the preliminary analyses performed for site selection of deep geological disposal of high-level waste (HLW) and spent fuel (SF), it was concluded that the most promising host rocks are the argillaceous sediments of the Sumer Formation (Lower Cretaceous), situated in the Western Fore-Balkan Mts. The present paper aims to compare the transport of three major radionuclides from a hypothetical radioactive waste disposal facility, which incorporates an engineering barrier of bentonite into the argillaceous (marl) medium. The simulations were performed by using HYDRUS-1D computer programme. The results are used for a preliminary estimation of argillaceous sediments as a host rock for geological disposal of HLW.

Thermal Analysis of Options for Spent Fuel Disposal in Switzerland

1996 ◽  
Vol 465 ◽  
Author(s):  
Tetsuo Sasaki ◽  
Kenichi Ando ◽  
Hideki Kaw Amura ◽  
Jürg W. Schneider ◽  
Ian G. McKinley
Keyword(s):  
Thermal Analysis ◽  
Basic Concept ◽  
Crystalline Basement ◽  
Opalinus Clay ◽  
High Level Waste ◽  
Spent Fuel ◽  
Compacted Bentonite ◽  
High Level ◽  
Host Rocks

ABSTRACTIn parallel to studies of disposal of vitrified high-level waste from reprocessing, projects have been initiated to examine options for direct disposal of spent fuel in Switzerland. The basic concept involves in-tunnel emplacement of encapsulated spent fuel in a deep repository which is backfilled with compacted bentonite. Two possible host rocks are considered - crystalline basement and Opalinus Clay. This paper reports the results of a thermal analysis which was carried out to evaluate constraints on repository layout set by the desire to limit temperatures experienced by the bentonite backfill.

The Deer Cove deposit, Baie Verte Peninsula, Newfoundland, a Paleozoic mesothermal lode-gold occurrence in the northern Appalachians

1993 ◽  
Vol 30 (7) ◽  
pp. 1532-1546 ◽  
Author(s):  
Karen S. Patey ◽  
Derek H. C. Wilton
Keyword(s):  
Volcanic Rocks ◽  
Wall Rock ◽  
Pure Gold ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Lode Gold ◽  
Basaltic Rocks ◽  
Gold Occurrence ◽  
Fracture Systems ◽  
Host Rocks

The Siluro-Devonian Deer Cove deposit, Baie Verte Peninsula, Newfoundland, is hosted by volcanic cover rocks of the Point Rousse Complex ophiolite. Mineralization consists of quartz vein lodes with gold, pyrite, lesser chalcopyrite, and minor arsenopyrite. Gold occurs as relatively pure gold intergrown with pyrite, and as solitary grains within the quartz gangue. Host rocks include basalt and gabbro at greenschist-facies metamorphic grade. The volcanic rocks have a general calcalkaline affinity, with (anhydrous) SiO2, TiO2, MgO, Al2O3, and Zr contents of 34–62%, 0.36–0.9%, 2.8–9%, 13.4–18.5%, and 28–48 ppm, respectively; Mg # ranges from 37 to 61. The host basaltic rocks were the products of island-arc or back-arc volcanism. Well-developed alteration haloes surround the quartz veins; the alteration grades from quartz–chlorite–carbonate in the veins, through sericitic wall rock, into propylitic (chlorite–epidote–carbonate–leucoxene) host rock. Trace-element geochemistry indicates that the ore fluids had large-ion lithophile element relationships similar to average crustal values. δ13C and δ18O values of carbonate separates range from −7 to −8‰ and 10 to 12‰, respectively. On the basis of geochemical, alteration, and isotopic data, the Deer Cove deposit should be classified as a typical mesothermal lode-gold occurrence. The veins apparently formed from mesothermal fluids with average crustal compositions that flowed along brittle fracture systems within the cover sequence during Siluro-Devonian Acadian deformation. As such the veins were unrelated to either sea-floor processes or Taconic ophiolite obduction. The vein systems apparently formed during transpressive tectonism which followed ocean closure and ophiolite obduction.

scholarly journals Evidence from the Kyrenia Range, Cyprus, of the northerly active margin of the Southern Neotethys during Late Cretaceous–Early Cenozoic time

2011 ◽  
Vol 149 (2) ◽  
pp. 264-290 ◽  
Author(s):  
ALASTAIR H. F. ROBERTSON ◽  
KEMAL TASLI ◽  
NURDAN İNAN
Keyword(s):  
Continental Margin ◽  
Carbonate Platform ◽  
Middle Eocene ◽  
Active Continental Margin ◽  
Volcanic Rocks ◽  
Basaltic Rocks ◽  
Tectonic Model ◽  
The North ◽  
Basic Volcanic ◽  
Upper Maastrichtian

AbstractSedimentary geology and planktonic foraminiferal biostratigraphy have shed light on the geological development of the northern, active continental margin of the Southern Neotethys in the Kyrenia Range. Following regional Triassic rifting, a carbonate platform developed during Jurassic–Cretaceous time, followed by its regional burial, deformation and greenschist-facies metamorphism. The platform was exhumed by Late Maastrichtian time and unconformably overlain by locally derived carbonate breccias, passing upwards into Upper Maastrichtian pelagic carbonates. In places, the pelagic carbonates are interbedded with sandstone turbidites derived from mixed continental, basic volcanic, neritic carbonate and pelagic lithologies. In addition, two contrasting volcanogenic sequences are exposed in the western-central Kyrenia Range, separated by a low-angle tectonic contact. The first is a thickening-upward sequence of Campanian–Lower Maastrichtian(?) pelagic carbonates, silicic tuffs, silicic lava debris flows and thick-bedded to massive rhyolitic lava flows. The second sequence comprises two intervals of basaltic extrusive rocks interbedded with pelagic carbonates. The basaltic rocks unconformably overlie the metamorphosed carbonate platform whereas no base to the silicic volcanic rocks is exposed. Additional basaltic lavas are exposed throughout the Kyrenia Range where they are dated as Late Maastrichtian and Late Paleocene–Middle Eocene in age. In our proposed tectonic model, related to northward subduction of the Southern Neotethys, the Kyrenia platform was thrust beneath a larger Tauride microcontinental unit to the north and then was rapidly exhumed prior to Late Maastrichtian time. Pelagic carbonates and sandstone turbidites of mixed, largely continental provenance then accumulated along a deeply submerged continental borderland during Late Maastrichtian time. The silicic and basaltic volcanogenic rocks erupted in adjacent areas and were later tectonically juxtaposed. The Campanian–Early Maastrichtian(?) silicic volcanism reflects continental margin-type arc magmatism. In contrast, the Upper Maastrichtian and Paleocene–Middle Eocene basaltic volcanic rocks erupted in an extensional (or transtensional) setting likely to relate to the anticlockwise rotation of the Troodos microplate.

Preferential sorption of radionuclides on different mineral phases typical for host rocks at the site of the future Russian high level waste repository

2019 ◽  
Vol 100 ◽  
pp. 90-95 ◽  
Author(s):  
Vladimir G. Petrov ◽  
Irina E. Vlasova ◽  
Anastasiya A. Rodionova ◽  
Vasily O. Yapaskurt ◽  
Vadim V. Korolev ◽  
...  
Keyword(s):  
High Level Waste ◽  
Mineral Phases ◽  
The Future ◽  
Waste Repository ◽  
Preferential Sorption ◽  
High Level ◽  
Host Rocks

Origin of appinitic pockets in the diorites of Jersey, Channel Islands

1977 ◽  
Vol 41 (318) ◽  
pp. 183-192 ◽  
Author(s):  
Colin H. Key
Keyword(s):  
Liquid Phase ◽  
Rapid Crystallization ◽  
Hollow Shell ◽  
Sudden Loss ◽  
Significant Enrichment ◽  
High Level ◽  
Host Rocks ◽  
Basic Rocks ◽  
Quench Crystallization ◽  
Volcanic Environment

SummaryIsolated pockets of pegmatitic appinite characterized by hollow-shell, prismatic amphiboles are common in the Pre-Cambrian metagabbros and metasomatic diorites of Jersey. Field relationships and petrography indicate a liquid phase in the formation of these appinitic pockets, which are chemically distinct from the associated gabbros and diorites. Close chemical ties between appinites and host rocks, however, prove a replacive, metasomatic, rather than intrusive origin for the pockets. Significant enrichment in SiO2, K2O, and Na2O suggest that surrounding granite provided the metasomatic agents. The localized changes in composition of the basic rocks resulted in the formation of partially molten pockets from which the appinites crystallized. This mechanism probably necessitates a temperature in the region of 900 °C at 2–5 Kb PH2O: Fractured, hollow-shell, prismatic amphiboles of the pockets are consistent with quench crystallization, possibly due to the sudden loss of volatiles. An increase in the oxygen fugacity may have played a major role in inducing the rapid crystallization of kaersutitic amphibole. The envisaged conditions under which these changes took place are those of a high-level, sub-volcanic environment.

scholarly journals Evaluation of temperature-induced effects on safety-relevant properties of clay host rocks with regard to HLW/SF disposal

2015 ◽  
Vol 79 (6) ◽  
pp. 1389-1395 ◽  
Author(s):  
M. Jobmann ◽  
A. Meleshyn
Keyword(s):  
Current Knowledge ◽  
Near Field ◽  
High Level Waste ◽  
Major Influence ◽  
Thermal Impact ◽  
Spent Fuel ◽  
Thermally Induced ◽  
Improved Performance ◽  
High Level ◽  
Host Rocks

AbstractDBE TECHNOLOGY, BGR and GRS are developing a methodology to demonstrate the safety of a repository for high-level waste and spent fuel (HLW/SF) in clays according to the requirements of the German regulating body. In particular, these requirements prescribe that the barrier effect of host rocks must not be compromised by a thermal impact resulting from HLW/SF emplacement. To substantiate and quantify this requirement, we carried out a literature survey of research on thermally-induced changes on clay properties. Effects thus compiled can be divided into thermo-hydro-mechanical and chemical-biological-mineralogical effects and were analysed with regard to their relevance to the integrity of clay host rocks. This analysis identified one effect of major influence within each group: thermal expansion and compaction as well as results of microbial activities. Importantly, it further revealed that a moderate temperature increase above 100°C cannot be expected to compromise the integrity of the geological barrier according to the current knowledge state. Evidence is presented in this paper that temperature increases up to 150°C can actually contribute to an improved performance of a radioactive waste repository by increasing the consolidation of the clay and sterilizing the repository's near-field to depress the deteriorative microbial effects. A quantitative temperature criterion for thermal impact of HLW/SF on clay host rocks is accordingly proposed.

The Kuh Toto volcanic-hosted copper deposit, Semnan Province, Iran: geochemical, fluid inclusion, and C and O isotopic studies

2021 ◽  
pp. geochem2021-018
Author(s):  
Omid Javariani ◽  
Farhad Ehya ◽  
Mohammad Ali Ali Abadi ◽  
Abbas Asgari ◽  
Mohammad Mehri
Keyword(s):  
Fluid Inclusion ◽  
Volcanic Rocks ◽  
Copper Deposit ◽  
Copper Ore ◽  
Copper Mineralization ◽  
Groundwater Environment ◽  
Oxygen Isotopic ◽  
Basic Volcanic ◽  
Host Rocks ◽  
Semnan Province

Supergene copper mineralization occurs at the Kuh Toto deposit, located 25 km to the west of Torud village in the Semnan Province, Iran. Mineralogical, fluid inclusion, and stable isotopic (C and O) studies, as well as rare earth element (REE) geochemistry of whole-rock and minerals are used to unravel the conditions under which the Cu ores formed. Malachite is the only copper ore mineral, and it is present as veinlets, coatings and small patches in Eocene volcanic rocks. Malachite is accompanied by minor calcite, manganese and iron oxides and oxyhydroxides, clay minerals, epidote, quartz, and chrysocolla. Argillic and, to a lesser extent, propylitic hydrothermal alteration partially affected the basic volcanic host rocks. The chondrite-normalized REE patterns of malachite and calcite are similar to those of the volcanic host rocks. They are enriched in LREEs. The volcanic host rocks are enriched in Cu (187 ppm on average). Fluid inclusions hosted in calcite reveal that calcite precipitated from hydrothermal fluids at low temperatures (69-150 °C) and low to moderate salinities (7.17-11.10 wt.% NaCl equivalent). The oxygen isotopic geothermometry yielded an average temperature of 41 °C for malachite formation. Geochemical and fluid inclusion evidence strongly support that mineral-forming elements, including Cu, originated from the associated volcanic rocks. Available data support the view that Cu was likely leached as mobile aqueous Cu2+ from the volcanic rocks by oxidizing surface waters. When Cu-enriched fluids entered the underlying groundwater environment, Cu was precipitated as malachite in fractures, via recombination with carbonate ions dissolved as CO2 in meteoric fluids.

Hydrogeological characteristics of candidate sites for high-level waste disposal in South Korea

2020 ◽  
Author(s):  
Jinyoung Park ◽  
Kyoungtae Ko ◽  
Minhee Lee ◽  
Minjune Yang
Keyword(s):  
Radioactive Waste ◽  
Crystalline Rock ◽  
High Level Waste ◽  
High Level Radioactive Waste ◽  
Rock Samples ◽  
Measurement Limit ◽  
Hydrogeological Characteristics ◽  
Average Porosity ◽  
High Level ◽  
Host Rocks

<p>Geological disposal of High-Level Radioactive Waste (HLRW) is considered to be one of the best disposal methods that can stably and semi-permanently isolate high-level radioactive waste from the biosphere. In this study, three types of potential host rocks for HLRW disposal were selected and the hydrogeological characteristics were investigated using deep drilling cores collected at about 50 m intervals in the borehole of a depth of 1 km. The rocks used in this study were granites and gneiss which are crystalline rock, and mudstone which is a sedimentary rock. The results of the study showed that the average porosity of granite was 0.48% and the permeability ranged from 7.87 × 10<sup>-19</sup> m<sup>2</sup> to 1.39 × 10<sup>-21</sup> m<sup>2</sup> except for samples outside the measurement limit (4.04 × 10<sup>-22</sup> m<sup>2</sup>). The average porosity of gneiss was 0.49% and the permeability ranged from 3.62 × 10<sup>-18</sup> m<sup>2</sup> to 4.58 × 10<sup>-22</sup> m<sup>2</sup>. The average porosity of mudstones was 3.62% and the values of permeability for most mudstone samples were lower than the measurement limit. For SEM-EDS analysis, many microcracks were observed in the crystalline rock samples having high permeability. On the other hand, there were almost no microcracks in crystalline rock samples having low permeability, and even if there were cracks, the cracks were filled with fillers such as clay minerals. These results indicate that the presence of microcracks or the filling of cracks in crystalline rocks has a significant effect on the flow of groundwater through the host rock.</p>

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