Geologic environments for nuclear waste repositories

© The Authors, published by EDP Sciences, 2017. High-level radioactive waste (HLW) results from spent reactor fuel and reprocessed nuclear material. Since 1957 the scientific consensus is that deep geologic disposal constitutes the safest means for isolating HLW for long timescales. Nuclear power is becoming significant for the Arab Gulf countries as a way to diversify energy sources and drive economic developments. Hence, it is of interest to the UAE to examine the geologic environments currently considered internationally to guide site selection. Sweden and Finland are proceeding with deep underground repositories mined in bedrock at depths of 500m, and 400m, respectively. Equally, Canada\u27s proposals are deep burial in the plutonic rock masses of the Canadian Shield. Denmark and Switzerland are considering disposal of their relative small quantities of HLW into crystalline basement rocks through boreholes at depths of 5,000m. In USA, the potential repository at Yucca Mountain, Nevada lies at a depth of 300m in unsaturated layers of welded volcanic tuffs. Disposal of low and intermediate-level radioactive wastes, as well as the German HLW repository favour structurally-sound layered salt stata and domes. Our article provides a comprehensive review of the current concepts regarding HLW disposal together with some preliminary analysis of potentially appropriate geologic environments in the UAE

BRACKISH MARSH BENTHIC MICROFAUNA AND PALEOENVIRONMENTAL CHANGES DURING THE LAST 6000 YEARS AT THE COASTAL PLAIN OF MARATHON (SE GREECE)

The present study, based mainly on the analysis of foraminifers and ostracodes, provides evidence of paleoenvironmental changes on the coastal plain of Marathon (E. Greece) during the last 6.000 yrs. Three sedimentary units -lagoonal formations - were recognized and identified as A, B and C. They range in time between before 5500BP-3500BP, 3500BP-2500BP and 2500BP-recent, respectively. The study of the brackish marsh microfauna of the Marathon plain Holocene sediments reveals the presence, during the last 5500 yrs., of three distinct biofacies in the sedimentary units already established. Alternating mesohaline - oligohaline (MO), oligohaline - fresh water (OFW) and mesohaline - oligohaline to oligohaline - fresh water (MO-OFW) biofacies in the framework of the sedimentary units indicate a general trend landward along the plain suggesting a slowing of sea-level rise probably correlated with a relevant tectonic uplift. One prominent feature of this study is the clarification of the ecological preference of the species Trichohya1us aguayoi (Bermudez, 1935), which is dominant in oligohaline conditions under an influence of fresh water input (salinity less than 15 ‰).&nbsp

The influence of the Evros River on the recent sedimentation of the inner shelf of the NE Aegean Sea

Abstract The transboundary Evros River discharges into the Alexandroupolis Gulf, located in the inner shelf of the northeastern Aegean Sea, where it has formed an extended delta. Grain-size and mineralogical analyses of five sediment cores, collected in the subaqueous delta, provide the following information about recent sedimentation processes in the northeastern part of the Aegean shelf: (a) river mouth deposits, consisting of coarse-grained sediments, are mainly deposited in front of the active mouth, whilst some sandy material is expected to be transported alongshore by nearshore currents; (b) delta front deposits are characterised by fine-grained sediments that include evidence of human activities which have taken place, in a more intense way, since the 1950s; and (c) prodelta deposits are represented by almost uniform riverine mud that cover the pre-existed relict sands of the shelf, indicating also the limit (some 15 km to the SW) of the influence of riverine sedimentation on the seabed of the inner shelf of the Alexandroupolis Gulf

Geomorphology and geoarchaeology: cross-contribution

2 page(s

Vulnerability assessment of archaeological sites to earthquake hazard: An indicator based method integrating spatial and temporal aspects

Across the world, numerous sites of cultural heritage value are at risk from a variety of human-induced and natural hazards such as war and earthquakes. Here we present and test a novel indicator-based method for assessing the vulnerability of archaeological sites to earthquakes. Vulnerability is approached as a dynamic element assessed through a combination of spatial and temporal parameters. The spatial parameters examine the susceptibility of the sites to the secondary Earthquake Environmental Effects of ground liquefaction, landslides and tsunami and are expressed through the Spatial Susceptibility Index (SSi). Parameters of physical vulnerability, economic importance and visitors density examine the temporal vulnerability of the sites expressed through the Temporal Vulnerability Index (TVi). The equally weighted sum of the spatial and temporal indexes represents the total Archaeological Site Vulnerability Index (A.S.V.I.). The A.S.V.I method is applied at 16 archaeological sites across Greece, allowing an assessment of their vulnerability. This then allows the establishment of a regional and national priority list for considering future risk mitigation. Results indicate that i) the majority of the sites have low to moderate vulnerability to earthquake hazard, ii) Neratzia Fortress on Kos and Heraion on Samos are characterised as highly vulnerable and should be prioritised for further studies and mitigation measures, and iii) the majority of the sites are susceptible to at least one Earthquake Environmental Effect and present relatively high physical vulnerability attributed to the existing limited conservation works. This approach highlights the necessity for an effective vulnerability assessment methodology within the existing framework of disaster risk management for cultural heritage.

Stratigraphy of “MOUN1” Drill Core: Discussion of Results

Appendix n°4 in the book : Lovén, B. & Sapountzis, I. The Ancient Harbours of the Piraeus, Volume III.2, The Themistoclean Shipsheds in Group 1 at Mounichia Harbour – Architecture, Topography and Finds. Monographs of the Danish Institute at Athens 15,5 (Aarhus University Press 2021)

The ancient harbours of the Piraeus: Stratigraphy of "Moun1" drill core: discussion of results

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