Evolution of the Earth's Crust with Waste Disposal
The Development of Complex Model of the Tectonic Evolution of Structural Blocks of Earth's Crust for Selecting Radioactive Waste Disposal Areas by the Example of Nizhnekansky Granitoid Massif
Tech Area / Field
- ENV-WDS/Waste Disposal/Environment
- OBS-GEO/Geology/Other Basic Sciences
3 Approved without Funding
VNIPI Promtechnology, Russia, Moscow
- Geophysical Center of Russian Academy of Sciences, Russia, Moscow
- Earth Data Network for Education and Scientific Exchange, France, Strasbourg\nBundesanstalt fur Geowissenschaften und Rohstoffe, Germany, Hannover\nSKB International Consultants AB, Sweden, Stockholm
Project summaryThe aim of the project is to elaborate the method to predict the evolution and persistence of structural tectonic blocks of the Earth’s crust with selecting sites for high level radioactive waste (HLRW) disposal on the basis of modeling time-space variations of stress and strain.
Disposal of HLRW in geological formations for a time of 104 – 105 years is at present the only possibility of its removal from the biosphere. Therefore selection of crustal sites in which the ecological safety of HLRW isolation is ensured for its lifetime is an acute problem of Russia and many developed countries. The technique of expert assessment of the geological environment in selecting sites for HLW disposal, which has been developed recently, only states the present geological situation and does not answer the question of how isolation properties of rocks will be changing under the effects of geodynamic processes in such a long time period.
From practical viewpoint, it is reasonable to predict crustal blocks evolution of Nizhnekansky granitoid massif in Russia where work is being carried out to select a site of underground laboratory construction. At the same time it is well known that this area belongs to the zone of active orogenesis and its long-term geodynamic stability has not been studied yet.
The elaboration of methods to predict tectonic blocks evolution when selecting sites HLRW disposal sites is based on the following principles:
- Evolution of the Earth’s crust is related to the intensity of tectonic processes development in the region. The decisive factor is the initial level of effective tectonic stresses, block structure of the environment and physical and mechanical features of a rock massif.
- Tectonic stress field varies in time and space retaining the inherited tendencies of the preceding period of the region tectonic development the indicator of which is the degree of dislocations, geomorphological characteristics and other features of the geological environment of the area.
- Modern stress and strain of the geological environment combined with the inherited time-space variation of local fields of tectonic stress determine the development of geomechanical processes of deformation and destruction in each inpidual region and the possibility of forming new tectonic faults or activating existing faults (zones of weakness and others).
It is planned to develop a dedicated finite-element program complex as a calculating tool of modeling stress and strain variation in rocks with time. The work involves the development of the project of geodynamic network arrangement and the first series of observations of recent movements of the Earth’s crust with space geodesy methods (effective navigation systems GPS and GLONASS and the European system Galileo, which is being developed now. The geodynamic network may subsequently become the basis of long-term monitoring system of modern movements of the Earth’s crust in the area of a future HLRW repository.
The projects includes the following five tasks:
- Elaborating methods of modeling tectonic evolution and destruction of tectonic blocks of the Earth’s crust;
- Summarizing data on tectonic conditions and reconstructing 3-D distribution of paleostress and deformation fields in the past period of time up to 1 million years.
- Developing finite-element complex to model tectonic processes in structural blocks for a long period of time;
- Developing the project and the arrangement of geodynamic observation network of modern crustal movements with space geodesy methods;
- Predicting long-term evolution of structural blocks and promising sites for HLRW disposal in Nizhnekansky granitoid massif.
In the course of the project we are planning to obtain the following major results of practical and fundamental significance:
- A new formulation of problems will be considered of the effects of faults activity and geodynamic and seismotectonic conditions on retaining isolation properties of blocks in the geological environment of areas where HLRW repositories may be located;
- Qualitative criteria will be proposed to estimate the stability of the Earth’s crust and predict its evolution in the context of the task set;
- Data on paleo and modern movements over the area for a time period of up to 1 -million year will be summarized;
- Paleo and modern stress field distribution will be reconstructed on the basis of geological and geomorphological methods and calculations of stress fields with the use of finite-element method;
- A project will be developed and geodynamic observation network will be arranged to monitor modern crustal movements with space geodesy methods;
- New knowledge will be obtained on the suitability of geological environment for long-term storage and disposal of HLRW in Nizhnekansky granitoid massif.
Prospective users of the results are designing institutes and enterprises of “Rosenergoatom” concern constructing a dry repository of HLRW and spent nuclear fuel (SNF) in the area of Zheleznogorsk. The results of the work on the project could be used to work out norms and methodical recommendations of the organization of the Federal Agency for Atomic Power and the Federal Service of Atomic Surveillance.
Project participants have a considerable experience of research in this field. They worked out the methods of the geological environment suitability assessment for locating especially important objects of nuclear fuel cycle. For many years they participated in planning and conducting scientific research on the underground objects of “Krasnoyarsk-26” complex, in Novaya Zemlya archipelago, underground nuclear explosions areas, and in uranium deposits in the territory of the former Soviet Union. Project participants are leaders in geological and tectonic substantiation of the site selection of underground nuclear power plants construction, in making geodynamic and seismological observations in operating nuclear power plants and others. They have a large experience in using information and computer technologies in ISTC projects no. 1536 and no. 2764 and a number of INTAS and Copernicus projects financed by EC.
Joining efforts of project participants will enable VNIPIpromtechnology specialists to be engaged in meeting civil challenges and to integrate into the international scientific community.
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