scholarly journals Active source seismic imaging on near-surface granite body: case study of siting a geological disposal repository for high-level radioactive nuclear waste

2021 ◽  
Author(s):  
Wen Li ◽  
Yi-Ke Liu ◽  
Yong Chen ◽  
Bao-Jin Liu ◽  
Shao-Ying Feng
Keyword(s):  
Nuclear Waste ◽  
Western China ◽  
Seismic Exploration ◽  
Contact Boundary ◽  
Near Surface ◽  
Geological Disposal ◽  
Active Source ◽  
Granite Body ◽  
High Level ◽  
Seismic Images

AbstractIn order to research whether it is suitable to set a geological disposal repository for high-level radioactive nuclear waste into one target granite body, two active source seismic profiles were arranged near a small town named Tamusu, Western China. The study area is with complex surface conditions, thus the seismic exploration encountered a variettraveltimey of technical difficulties such as crossing obstacles, de-noising harmful scattered waves, and building complex near-surface velocity models. In order to address those problems, techniques including cross-obstacle seismic geometry design, angle-domain harmful scattered noise removal, and an acoustic wave equation-based inversion method jointly utilizing both the and waveform of first arrival waves were adopted. The final seismic images clearly exhibit the target rock’s unconformable contact boundary and its top interface beneath the sedimentary and weathered layers. On this basis, it could be confirmed that the target rock is not thin or has been transported by geological process from somewhere else, but a native and massive rock. There are a few small size fractures whose space distribution could be revealed by seismic images within the rock. The fractures should be kept away. Based on current research, it could be considered that active source seismic exploration is demanded during the sitting process of the geological disposal repository for nuclear waste. The seismic acquisition and processing techniques proposed in the present paper would offer a good reference value for similar researches in the future.

scholarly journals A Critical Review of the Recent Improvements in Minimizing Nuclear Waste by Innovative Gas-Cooled Reactors

2008 ◽  
Vol 2008 ◽  
pp. 1-18 ◽  
Author(s):  
E. Bomboni ◽  
N. Cerullo ◽  
G. Lomonaco ◽  
V. Romanello
Keyword(s):  
Nuclear Waste ◽  
Critical Review ◽  
Simplified Models ◽  
Geological Disposal ◽  
Fuel Cycles ◽  
Multiple Recycling ◽  
High Level ◽  
Coupling Current ◽  
The University

This paper presents a critical review of the recent improvements in minimizing nuclear waste in terms of quantities, long-term activities, and radiotoxicities by innovative GCRs, with particular emphasis to the results obtained at the University of Pisa. Regarding these last items, in the frame of some EU projects (GCFR, PUMA, and RAPHAEL), we analyzed symbiotic fuel cycles coupling current LWRs with HTRs, finally closing the cycle by GCFRs. Particularly, we analyzed fertile-free and Pu-Th-based fuel in HTR: we improved plutonium exploitation also by optimizing Pu/Th ratios in the fuel loaded in an HTR. Then, we chose GCFRs to burn residual MA. We have started the calculations on simplified models, but we ended them using more “realistic” models of the reactors. In addition, we have added the GCFR multiple recycling option usingkeffcalculations for all the reactors. As a conclusion, we can state that, coupling HTR with GCFR, the geological disposal issues concerning high-level radiotoxicity of MA can be considerably reduced.

Applying integrated seismic technology to complex foothill areas of foreland basins in China

2019 ◽  
Vol 38 (8) ◽  
pp. 597-603
Author(s):  
Yong Fang ◽  
Wenshan Luo ◽  
Xiaoxia Luo ◽  
Xukui Feng ◽  
Bo Zhao ◽  
...  
Keyword(s):  
Seismic Data ◽  
Model Building ◽  
New Technologies ◽  
High Density ◽  
Hydrocarbon Exploration ◽  
Western China ◽  
Seismic Exploration ◽  
Foreland Basins ◽  
Near Surface ◽  
True Surface

Due to complicated near-surface conditions, including large elevation changes and complex geologic structures, accurate imaging of subsurface structures for hydrocarbon exploration in the foreland basins of western China has been challenging for many years. After decades of research and fieldwork, we developed an effective seismic exploration workflow that uses the latest technologies from acquisition to imaging. They include 3D high-density and wide-azimuth (WAZ) acquisition, 3D true-surface tilted transverse isotropy (TTI) anisotropic prestack depth migration, and dual-detachment structural modeling and interpretation. To further reduce uncertainty in velocity model building and improve imaging quality, our geologists, geophysicists, and reservoir engineers worked closely through the exploration cycle (seismic acquisition, processing, and interpretation). This exploration model has been used successfully in hydrocarbon exploration of many complex foothill areas in western China. Three-dimensional WAZ high-density seismic surveys have been conducted over 40,000 km2 of the foreland basins, greatly improving the field seismic data quality. After application of 3D true-surface TTI anisotropic depth model building and imaging with integrated structural interpretation, new discoveries of hydrocarbon reservoirs have increased. The application of new technologies not only increased drilling success but also reduced depth well-tie errors between seismic data and wells.

The Effect of Chloride Concentration on Crevice Corrosion of some Welded Titanium Alloys

2008 ◽  
Vol 59 (2) ◽  
pp. 140-144
Author(s):  
Laurentiu Popa ◽  
Maria Radulescu ◽  
Alice Dinu ◽  
Lucian Velciu ◽  
Ioan Viorel Branzoi
Keyword(s):  
Waste Management ◽  
Titanium Alloys ◽  
Nuclear Waste ◽  
Crevice Corrosion ◽  
Chloride Concentration ◽  
Geological Disposal ◽  
Buffer Material ◽  
High Level Nuclear Waste ◽  
High Level

Geological disposal is identified by nearly all experts in the field of waste management as the only safe and sustainable option presently available, but the progress towards its implementation is slow. The nuclear waste must be safely storaged for hundreds of thousand years. Titanium alloys are some of the most promising candidates as container materials for the long-term disposal of high level nuclear waste (HLW) in rock salt formations. In the case of titanium waste containers, between the containers walls and the surrounding buffer material used to pack the disposal borehole some crevices can appear in the welded zone container/ shielding lid, under a biofilm etc. For this purpose we studied the effect of chloride concentration on crevice corrosion of some welded titanium alloys (Grade 2 and Grade 12, respectively) in chloride solutions at 90oC by electrochemical methods (Ecorr vs time, potentiodynamic tests).

scholarly journals Determination of the Forward Dissolution Rate for International Simple Glass in Alkaline Solutions

MRS Advances ◽  
2017 ◽  
Vol 2 (12) ◽  
pp. 661-667 ◽  
Author(s):  
Alice Elia ◽  
Karine Ferrand ◽  
Karel Lemmens
Keyword(s):  
Dissolution Rate ◽  
Nuclear Waste ◽  
International Collaboration ◽  
Alkaline Solutions ◽  
Alkaline Ph ◽  
Geological Disposal ◽  
Ph Range ◽  
High Level ◽  
Good Agreement

ABSTRACTThe International Simple Glass (ISG) is considered as reference benchmark glass and is used in the frame of an international collaboration for the study of the dissolution mechanisms of high-level vitrified nuclear waste.In this work the forward dissolution rate of the ISG was determined in different alkaline solutions, as a simulation of the disposal conditions foreseen by the Belgian concept for geological disposal of vitrified waste. The determination of the forward dissolution rate was done by measuring the Si released from the glass in solution in tests performed at 30 °C in four different KOH solutions with pH varying from 9 to 14 and in artificial cementitious water at pH 13.5.The forward dissolution rates determined for the ISG in high pH solutions are in good agreement with the results obtained for a lower pH range.The rates obtained in this study, moreover, were compared with the rates measured in the same conditions for SON68 glass from a previous work. The values obtained for the two glasses are comparable in artificial cementitious water and in KOH at moderately alkaline pH. At higher pH, ISG glass shows a lower forward dissolution rate with respect to SON68 (0.20 g·m-2·d for ISG and 0.35 g·m-2 d for SON68 at pH 14).

Critical Conditions for Initiation of Localized Corrosion of Mild Steels in Contact with Bentonite Used in Geological Disposal Packages of Nuclear Waste

1992 ◽  
Vol 294 ◽  
Author(s):  
Guen Nakayama ◽  
Masatsune Akashi
Keyword(s):  
Mild Steel ◽  
Nuclear Waste ◽  
Localized Corrosion ◽  
Critical Conditions ◽  
Geological Disposal ◽  
Alkaline Environments ◽  
Current Design ◽  
Long Time ◽  
High Level Nuclear Waste ◽  
High Level

ABSTRACTIn the current design of geological disposal of high-level nuclear waste, the use of bentonite to stand as an artificial barrier-cum-buffer between the host rock and the packages made of mild steel is being investigated. Although mild steels commomly have been considered to be passivity in alkaline environments, under certain circumstances, they become liable to localized corrosion, e.g., pitting corrosion and crevice corrosion. Since bentonite can turn the environment alkaline to a pH of approximately 10 when it is mixed with groundwater, critical conditions for the initiation of localized corrosion of mild steel must be known to evaluate the extremely long time integrity of disposal packages serving in such an environment. This paper presents and discusses the observations and results acquired in a series of critical conditions for the initiation of localized corrosion of mild steels in various groundwater-bentonite environments at 20C, with a deaerated aqueous solution of 1 mMol/L [HCO3−] +10 ppm [CI−], simulating the natural groundwater and varying the bentonite content.

Sign in / Sign up

Export Citation Format

Share Document