Altered Crystalline Rock Distributed Along Groundwater Conductive Fractures and the Retardation Capacity in the Orogenic Field of Japan

2009 ◽  
Author(s):  
Hidekazu Yoshida ◽  
Shoji Nishimoto ◽  
Richard Metcalfe
Keyword(s):  
Radioactive Waste ◽  
Barrier Function ◽  
Chemical Characterization ◽  
Crystalline Rock ◽  
Crystalline Rocks ◽  
Rock Interaction ◽  
Physico Chemical ◽  
High Level ◽  
A Site ◽  
Accessible Porosity

In the orogenic field Japanese islands, there are wide areas of crystalline rocks that inevitably contain groundwater conductive fractures associated with alteration zones. However, little attention has been given to the formation process and possible influence on the radionuclides migration from radioactive waste repository that might be sited within crystalline rock. In particular, the influences of alteration minerals and microfractures, due to chemical sorption and/or physical retardation are required to assess the realistic barrier function. In order to understand the alteration process and the retardation capacity, detailed mineralogical and physico-chemical characterization of altered crystalline rocks have been carried out. Mineralogical analysis reveals that the altered crystalline rocks have been formed through basically two stages of water-rock interaction during and after uplift. Physico-chemical characteristics including laboratory sorption experiments show that altered crystalline rock has a certain volume of accessible porosity, particularly in plagioclase grains, which would influence on nuclide retardation more than the accessible porosity in other minerals present, such as biotite. These results provide confidence that even altered and fractured parts of any crystalline rock that might be encountered in a site for the disposal of high-level radioactive waste may still play a role of barrier function.

scholarly journals Preliminary safety analyses in the high-level radioactive waste site selection procedure in Germany

2021 ◽  
Vol 56 ◽  
pp. 67-75
Author(s):  
Eva-Maria Hoyer ◽  
Elco Luijendijk ◽  
Paulina Müller ◽  
Phillip Kreye ◽  
Florian Panitz ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Site Selection ◽  
Selection Procedure ◽  
Crystalline Rock ◽  
Radioactive Waste Disposal ◽  
High Level Radioactive Waste ◽  
Long Term Storage ◽  
Geological Conditions ◽  
High Level ◽  
A Site

Abstract. The Federal Company for Radioactive Waste Disposal (BGE) is responsible for the search for a site with the best possible safety for the disposal of high-level radioactive waste in Germany. The site selection procedure is regulated in a law that was adopted by the German Federal Parliament (Repository Site Selection Act – StandAG, 2017, last updated 2020) and aims to be a participatory, transparent, learning, and self-questioning process based on scientific expertise. The first step of the first phase of the site selection procedure was completed in September 2020 and resulted in the identification of sub-areas that give reason to expect favorable geological conditions for the long-term storage of nuclear waste in the subsurface. These sub-areas cover approximately 54 % of Germany and are located in three different host rocks: rock salt – halite, claystone, and crystalline rock. The challenge for the next step is to find suitable siting regions within the previously determined sub-areas that are then considered further in the next phase of the site selection procedure. In the following, the methodology of the so-called representative preliminary safety analyses is described, which constitute one of the tools to identify siting regions, and some first insight on how they are planned to be implemented in practice is given.

Aqueous Phase Diffusion in Crystalline Rock

1981 ◽  
Vol 11 ◽  
Author(s):  
M.H. Bradbury ◽  
D. Lever ◽  
D. Kinsey
Keyword(s):  
Radioactive Waste ◽  
Aqueous Phase ◽  
Water Movement ◽  
Degradation Products ◽  
Crystalline Rock ◽  
Crystalline Rocks ◽  
Radionuclide Transport ◽  
Fracture Networks ◽  
Phase Diffusion ◽  
Main Factors

One of the options being considered for the disposal of radioactive waste is deep burial in crystalline rocks such as granite. It is generally recognised that in such rocks groundwater flows mainly through the fracture networks so that these will be the “highways” for the return of radionuclides to the biosphere. The main factors retarding the radionuclide transport have been considered to be the slow water movement in the fissures over the long distances involved together with sorption both in man-made barriers surrounding the waste, and onto rock surfaces and degradation products in the fissures.

Determination of the characteristics of crystalline rocks by field experiments: a review

1986 ◽  
Vol 319 (1545) ◽  
pp. 139-156 ◽  
Keyword(s):  
Radioactive Waste ◽  
Field Experiments ◽  
The United States ◽  
Crystalline Rocks ◽  
Granitic Rocks ◽  
Rock Types ◽  
Basement Rocks ◽  
Deep Boreholes ◽  
High Level ◽  
Underground Research Laboratory

Crystalline rocks, particularly granitic rocks and basalts, are one of the principal rock types under consideration as a potential host rock for a high-level radioactive waste repository. Permeability in such rocks is related to discontinuities of various scales, and the quantification and prediction of groundwater flow within both the fractures and the intact rock between the fractures is the major goal of field experiments. The Canadian Underground Research Laboratory is unique in that the hydrogeological conditions within a large volume of rock surrounding the experimental shaft are being monitored before, during and after excavation and the results compared with model predictions. In Switzerland twelve deep boreholes are being drilled to over 1000 m to investigate crystalline basement rocks beneath a cover of sediments. The Stripa Mine in Sweden has hosted a major experimental programme including heater tests to stimulate the thermal effect of radioactive waste and hydrogeological tests at various scales down to individual fractures. The United States of America, the United Kingdom, France and Finland have also embarked on major experimental programmes. Continuing research is needed, with an emphasis on field experiments and research in underground rooms, to provide the data on which detailed risk assessments can be based.

Which Processes could define Temperature Limits on the Outer Surface of a Container in a Disposal Facility ?

2020 ◽  
Author(s):  
Guido Bracke ◽  
Eva Hartwig-Thurat ◽  
Jürgen Larue ◽  
Artur Meleshyn ◽  
Torben Weyand ◽  
...  
Keyword(s):  
Outer Surface ◽  
Site Selection ◽  
Selection Process ◽  
Temperature Limit ◽  
Crystalline Rock ◽  
Safety Concept ◽  
Disposal Facility ◽  
High Level ◽  
A Site ◽  
Host Rocks

<p>When the recommencement of the search for and selection of a site for a disposal facility for HLRW in Germany was stipulated by the Site Selection Act (StandAG 2017) in 2017, a <strong>precautionary </strong>temperature limit of 100 °C on the outer surface of the containers with high-level radioactive waste in the disposal facility section was set. This <strong>precautionary </strong>temperature limit shall be applied in preliminary safety analyses provided that the “maximum physically possible temperatures” in the respective host rocks have not yet been determined due to pending research. Therefore, this issue is addressed and discussed in this paper, contributing to “pending research” by a review of the literature.</p><p>This presentation briefly discusses a few examples of thermohydraulical, mechanical, chemical and biological processes in a disposal facility, because temperature limits are derived based on safety impacts regarding THMCB-processes. The temperature-dependent processes have been extracted from databases for features, events and processes (FEP-databases). Furthermore, it is dicussed if the feasibility to retrieve and recover HLRW is hampered at high temperatures.</p><p>It is concluded that a design temperature concerning single components of a disposal facility for the preservation of their features can be derived when a safety concept is established. However, the interactions of all relevant processes in a disposal concept must be considered to determine a specific temperature limit for the outer surface of the containers. Therefore, applicable temperature limits may vary for particular safety and disposal concepts in the following host rocks: rock salt, clay stone and crystalline rock.</p><p>Technical solutions for retrieval and design options for recovery seem to be viable up to temperatures of 200 °C with different, sometimes severe, downsides according to expert judgement.</p><p>It is summarized that emperature limits regarding the outer surface of the containers can be derived specifically for each safety concept and design of the disposal facility in a host rock. General temperature limits without reference to specific safety concepts or the particular design of the disposal facility may narrow down the possibilities for optimisation of the disposal facility and could adversely affect the site selection process in finding the best suitable site.</p>

scholarly journals Development of a database for the analysis of the disposal system in the representative preliminary safety analysis

2021 ◽  
Vol 1 ◽  
pp. 39-40
Author(s):  
Eva-Maria Hoyer ◽  
Paulina Müller ◽  
Phillip Kreye ◽  
Christoph Behrens ◽  
Marc Wengler ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Site Selection ◽  
Selection Procedure ◽  
Crystalline Rock ◽  
Radioactive Waste Disposal ◽  
Future Evolution ◽  
Technical Parameters ◽  
Geological Setting ◽  
Geological Conditions ◽  
High Level

Abstract. The Federal Company for Radioactive Waste Disposal (BGE) is the German waste management organisation responsible for implementing the search for a site with the best possible safety for the disposal of high-level radioactive waste for at least 1 million years, following the amendments of the Repository Site Selection Act in 2017. The selection procedure is meant to be a participatory, transparent, learning and self-questioning process based on scientific expertise. It consists of three phases with an increasing level of detail. The first step of the first phase of the site selection procedure was completed in September 2020 and resulted in the identification of 90 subareas that give reason to expect favourable geological conditions for the safe disposal. The potentially suitable subareas cover approximately 54 % of Germany and are located in three different host rocks: rock salt (halite), claystone and crystalline rock. The second step of phase one is currently in progress and includes the so-called representative preliminary safety analyses that aim to assess the extent to which the safe containment of the radioactive waste can be expected. Representative preliminary safety analyses are one of the foundations for deciding whether an area will be considered for surface-based exploration in the next phase of the site selection procedure. Within the preliminary safety analyses, the behaviour of the disposal system is analysed in its entirety, across all operational phases of the repository and under consideration of possible future evolution of the disposal system with respect to the safe containment of the radioactive waste. The development of a database is described, which aims to systematically document and provide the framework needed for the analyses of the disposal systems in the subareas regarding the safe containment of the radionuclides over the assessment period of 1 million years. This database includes the vast amount of information about the different components of the disposal system. This includes also the geological setting, the technical conception of the repository and compilations of values for the physical, geoscientific, and technical parameters characterising the various barriers of the disposal system. Furthermore, a self-contained derivation of expected and deviating future evolution of the disposal system and its geological setting is included; following the so-called features, events and processes (FEP) strategy.

scholarly journals Identification and evaluation of processes for joint disposal of high level radioactive waste and low to intermediate level radioactive waste

2021 ◽  
Vol 1 ◽  
pp. 183-184
Author(s):  
Andreas Poller ◽  
Susie M. L. Hardie ◽  
Gerhard Mayer ◽  
Marie Pijorr ◽  
Joachim Poppei ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Selection Procedure ◽  
Crystalline Rock ◽  
Intermediate Level ◽  
Clay Rock ◽  
High Level Radioactive Waste ◽  
Quantitative Analyses ◽  
Intermediate Level Radioactive Waste ◽  
High Level ◽  
Qualitative Analyses

Abstract. The on-going research project „Identification and evaluation of processes that can arise by disposing of both high level radioactive waste (HAW) and low to intermediate level radioactive waste (LAW/MAW) at the same site“ (GemEnd, FKZ 4719F10401), commissioned by the Federal Office for the Safety of Nuclear Waste Management (BASE), is concerned with the question which thermal, hydraulic, mechanical, chemical and biological (THMCB) processes could be of importance for the long-term safety of the geological repository for high level radioactive waste. The focus of the project is on mutual influences between the HAW and LAW/MAW repositories, which should be constructed separately according to the Safety Regulations (Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, BMU, 2020). A second point of emphasis is on processes that could result from the disposal of small amounts of LAW/MAW within the HAW repository. The analyses carried out for each of the potential host rocks clay rock, rock salt and crystalline rock as well as for a combination of clay rock above crystalline rock at a generic site are divided into a qualitative and a quantitative part. As for the qualitative analyses, all potentially relevant processes are identified and evaluated as to whether they are negligible or principally relevant for the exemplary repository configurations considered and according to the current state of knowledge. With regard to the quantitative analyses, the possible extent of potentially safety-relevant processes is illustrated by means of coupled numerical simulations. Of special interest are the effects of particularly sensitive model approaches and/or parameters and notably of the distances between the HAW and LAW/MAW repositories in the different exemplary repository configurations considered. From the results of the quantitative and qualitative analyses, knowledge gaps will be identified and the possibility of their reduction by research and development activities will be discussed. Furthermore, aspects of the transferability of the results to the German site selection procedure will be illuminated. At the interdisciplinary research symposium safeND selected preliminary results of both the qualitative and quantitative analyses will be presented.

scholarly journals Status of Deep Borehole Disposal of High-Level Radioactive Waste in Germany

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2580 ◽  
Author(s):  
Guido Bracke ◽  
Wolfram Kudla ◽  
Tino Rosenzweig
Keyword(s):  
Radioactive Waste ◽  
Site Selection ◽  
Real Option ◽  
Selection Process ◽  
Technical Equipment ◽  
Deep Borehole ◽  
Final Disposal ◽  
High Level Radioactive Waste ◽  
High Level ◽  
A Site

The phase-out of nuclear energy in Germany will take place in 2022. A site for final disposal of high-level radioactive waste (HLRW) has not yet been chosen, but a site selection process was restarted by the Site Selection Act in 2017. This Act was based on a recommendation by a commission which also advised to follow up the development of deep borehole disposal (DBD) as a possible option for final disposal of HLRW. This paper describes briefly the status of DBD in Germany and if this option is to be pursued in Germany. Although DBD has some merits, it can only be a real option if supported by research and development. The technical equipment for larger boreholes of the required size will only be developed if there is funding and a feasibility test. Furthermore, any DBD concept must be detailed further, and some requirements of the Act must be reconsidered. Therefore, the support of DBD will likely remain at a low level if there are no political changes.

Liquid Chromatography in Migration Studies

1981 ◽  
Vol 11 ◽  
Author(s):  
Lars Carlsen ◽  
Walther Batsberg
Keyword(s):  
Liquid Chromatography ◽  
Radioactive Waste ◽  
Experimental Technique ◽  
Chemical Properties ◽  
Detailed Knowledge ◽  
Geochemical Environment ◽  
Physico Chemical ◽  
The Media ◽  
A Site ◽  
Sorption Characteristics

A detailed knowledge of the geochemical environment of a site for the disposal of radioactive waste is of fundamental importance. To evaluate the migration behaviour of radionuclides in geological media a series of data are needed, amongst others a number of physico-chemical properties of the media, such as permeability, porosity, dispersion-, diffusion-, and sorption characteristics. In this connection liquid chromatography appears to be advantageous as a facile experimental technique to obtain relevant data for these physico-chemical properties.

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