scholarly journals Can a repository site be safer than safe? – Criteria and methods for a safety-oriented comparison of repository sites

2021 ◽  
Vol 1 ◽  
pp. 41-42
Author(s):  
Martin Navarro ◽  
Ingo Kock ◽  
Gerd Frieling ◽  
Thomas Beuth
Keyword(s):  
Site Selection ◽  
Selection Procedure ◽  
Evaluation Methods ◽  
Safety Concept ◽  
Joint Project ◽  
Safety Requirements ◽  
Operational Criteria ◽  
Host Rocks ◽  
Final Selection ◽  
Selection Phase

Abstract. In the course of the German site selection procedure, repository potential sites will be rejected if it becomes apparent that they will probably not meet the regulatory safety requirements (EndlSichAnfV). It is therefore likely that the remaining sites of the final selection phase (which is specified by paragraph 19 of the StandAG) will meet the safety requirements and are therefore capable of being approved. Under these circumstances, finding the site with the highest possible level of safety (as required by the StandAG) calls for a further differentiation of safety above the level of safety that is prescribed by the safety requirements. Based on this differentiation, operational criteria have to be developed for a safety-oriented comparison of repository sites and systems; however, finding suitable criteria is not a trivial task if the repository systems that are available for selection make use of different host rocks and therefore differ with respect to the internal structure and safety concept. Between 2007 and 2010, criteria and associated evaluation methods for a safety-oriented comparison of approvable repository sites were developed by project 3607R02589 of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) within the joint project VerSi. The robustness of the repository system was proposed as a central criterion for site comparison. In the years to follow, criteria and evaluation methods were tested and refined by BfE/BMU projects 05504/2 and 4719E03250, which finally showed a substantial need for further research and development. The presentation outlines the results of these three projects and discusses the questions that are still open.

Significance of long-term climate evolution and associated impacts on the long-term safety of a high-level radioactive waste repository within the German siting process

2021 ◽  
Author(s):  
Marc Wengler ◽  
Astrid Göbel ◽  
Eva-Maria Hoyer ◽  
Axel Liebscher ◽  
Sönke Reiche ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Site Selection ◽  
Phase 1 ◽  
High Level Radioactive Waste ◽  
Safety Requirements ◽  
Climate Evolution ◽  
Safety Assessments ◽  
High Level ◽  
Host Rocks

<p>According to the 'Act on the Organizational Restructuring in the Field of Radioactive Waste Disposal' the BGE was established in 2016. The amended 'Repository Site Selection Act' (StandAG) came into force in July 2017 and forms the base for the site selection by clearly defining the procedure. According to the StandAG the BGE implements the participative, science-based, transparent, self-questioning and learning procedure with the overarching aim to identify the site for a high-level radioactive waste (HLW) repository in a deep geological formation with best possible safety conditions for a period of one million years.</p><p>The German site selection procedure consists of three phases, of which Phase 1 is divided into two steps. Starting with a blanc map of Germany, the BGE completed Step 1 in September 2020 and identified 90 individual sub-areas that provide favorable geological conditions for the safe disposal of HLW in the legally considered host rocks; rock salt, clay and crystalline rock. Based on the results of Step 1, the on-going Step 2 will narrow down these sub-areas to siting regions for surface exploration within Phase 2 (§ 14 StandAG). Central to the siting process are representative (Phase 1), evolved (Phase 2) and comprehensive (Phase 3) preliminary safety assessments according to § 27 StandAG.</p><p>The ordinances on 'Safety Requirements' and 'Preliminary Safety Assessments' for the disposal of high-level radioactive waste from October 2020 regulate the implementation of the preliminary safety assessments within the different phases of the siting process. Section 2 of the 'Safety Requirements' ordinance provides requirements to evaluate the long-term safety of the repository system; amongst others, it states that all potential effects that may affect the long-term safety of the repository system need to be systematically identified, described and evaluated as “expected” or “divergent” evolutions. Additionally, the ordinance on 'Preliminary Safety Assessments' states in § 7, amongst others, that the geoscientific long-term prediction is a tool to identify and to evaluate geogenic processes and to infer “expected” and “divergent” evolutions from those. Hence, considering the time period of one million years for the safe disposal of the HLW and the legal requirements, it is essential to include long-term climate evolution in the German site selection process to evaluate the impact of various climate-related scenarios on the safety of the whole repository system.</p><p>To better understand and evaluate the influence of climate-related processes on the long-term safety of a HLW repository, climate-related research will be a part of the BGE research agenda. Potential research needs may address i) processes occurring on glacial – interglacial timescales (e.g. the inception of the next glaciation, formation and depth of permafrost, glacial troughs, sub-glacial channels, sea-level rise, orbital forcing) and their future evolutions, ii) effects on the host rocks and the barrier system(s) as well as iii) the uncertainties related to these effects but also to general climate models and predictions.</p>

Methodology of preliminary safety assessments in the site selection procedure in Germany

2020 ◽  
Author(s):  
Wolfram Rühaak ◽  
Phillip Kreye ◽  
Eva-Maria Hoyer ◽  
Johanna Wolf ◽  
Florian Panitz ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Site Selection ◽  
Reactive Transport ◽  
Selection Procedure ◽  
Transport Modelling ◽  
Safety Requirements ◽  
Safety Assessments ◽  
High Level ◽  
Geological Formations

<p><span>In Germany, the site selection for a repository for radioactive waste in deep geological formations was (re-) started in 2017 with the Repository Site Selection Act coming into force. The Site Selection Act envisages preliminary safety assessments as a measure to ensure the safety of a considered site.</span></p><p><span>The focus of the presentation will be the methodology of the preliminary safety assessments as it is derived from the legal requirements. In this context, the Federal Ministry for Environment, Nature Conservation and Nuclear Safety published the draft of the regulation on the safety requirements for the disposal of high-level radioactive waste in summer 2019. Article 2 of this regulation contains the requirements for the implementation of preliminary safety assessments in the site selection procedure. One essential aspect is the systematical identification and characterization of uncertainties. We will discuss the key features of the handling of uncertainties in the site selection procedure, especially with regard to numerical reactive transport modelling. The German Site Selection Act is divided into several steps with increasing level of detail. The identification and quantification of uncertainties plays a major role to improve quality and plausibility in each step. Well-prepared explorations for instance, need to be addressed in a way to minimise data uncertainties. In addition, the handling of uncertainties in safety assessments on an international level is evaluated. </span></p>

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 Site Selection for Joint Logistics over the Shore (JLOTS) Operations Using Multi- Objective Decision Analysis

2016 ◽  
Vol 4 (2) ◽  
pp. 88-95
Author(s):  
Mike Evans ◽  
Mike Lami ◽  
Brendan Madarasz ◽  
Benjamin Smith ◽  
Chris Green
Keyword(s):  
Decision Analysis ◽  
Site Selection ◽  
Decision Support Tool ◽  
Military Operations ◽  
Support Tool ◽  
Multi Objective ◽  
Selection Protocol ◽  
Operational Criteria ◽  
A Site ◽  
Development Center

As the U.S. military faces an increasing need to deploy across a range of military operations and environments, the ability to establish and sustain logistics support remains a major challenge. The Engineer Research and Development Center is currently developing the Planning Logistics Analysis Network System (PLANS), a decision support tool, to facilitate strategic and operational logistics planning. This paper describes a site selection protocol for logistics operations occurring without a suitable port, commonly referred to as Logistics over-the Shore (LOTS) operations. The model uses multi- objective decision analysis techniques to weight different operational criteria to determine the best overall site for logistics over the shore operations. This tool will enhance the time and accuracy in determining an optimal site that meets the decision maker’s specific operational needs.

Development of Siting Factors and Commencement of Open Solicitation for Preliminary Investigation Areas of HLW disposal in Japan

2003 ◽  
Vol 807 ◽  
Author(s):  
Hiroyuki Tsuchi ◽  
Masanori Kobayashi ◽  
Hirofumi Kondo ◽  
Akihisa Koike ◽  
Hiroki Hatamoto ◽  
...  
Keyword(s):  
Waste Management ◽  
Nuclear Waste ◽  
Site Selection ◽  
Preliminary Investigation ◽  
Selection Procedure ◽  
Nuclear Waste Management ◽  
Management Organization ◽  
The Way

ABSTRACTThe Nuclear Waste Management Organization of Japan (NUMO) has developed a set of “Siting Factors (SFs)” to guide choice of preliminary investigation areas (PIAs) of HLW disposal. A call for municipalities to volunteer PIAs was initiated, which included published SFs, in December 2002 as the first stage of a stepwise site selection procedure. This paper describes the way that SFs were developed and the outlines how they will be applied.

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 Section 14 StandAG – Identification of siting regions and associated challenges

2021 ◽  
Vol 1 ◽  
pp. 49-50
Author(s):  
Lisa Seidel ◽  
Marc Wengler
Keyword(s):  
Radioactive Waste ◽  
Phase I ◽  
Site Selection ◽  
Selection Procedure ◽  
Radioactive Waste Disposal ◽  
Second Step ◽  
High Level Radioactive Waste ◽  
Surface Exploration ◽  
Safety Assessments ◽  
High Level

Abstract. With the publication of the subarea interim report on sub-regions on 28 September 2020, the Federal Company for Radioactive Waste Disposal (BGE), as the implementer of the German site selection procedure, has completed the first step of phase I in due time. The second step of phase I is the identification of siting regions for surface exploration. In the following step 2 of phase I, the determination of siting regions for surface exploration will be carried out based on the interim results of the first step of phase I in accordance with section 14 of the regulating law (StandAG). A central component of this second step of phase I is the representative preliminary safety assessments pursuant to section 27 StandAG, the ordinances on “Safety Requirements” (EndlSiAnfV) and “Preliminary Safety Assessments” (EndlSiUntV), which are carried out for each of the sub-regions. Based on the results of the preliminary safety assessments and the renewed application of the geoscientific weighting criteria (section 24 StandAG), siting regions will be identified that have the potential to become the site with the best possible safety for a repository for high-level radioactive waste. During the second step of phase I, the planning scientific consideration criteria (section 25 StandAG) can be applied for the first time. The path to the siting regions for surface exploration can be accompanied by various challenges related to geoscientific, methodological and also societal questions. For example, the application of the representative preliminary safety assessments may be more challenging in larger subareas compared to smaller ones as subsurface properties are likely to be more variable. In this context, areas with little data coverage for example, and the treatment of these areas in the procedure may pose another challenge. Therefore, sound methodological concepts must be developed for performing the representative preliminary safety assessments as well as for applying the geoscientific weighting criteria. Furthermore, the German site selection procedure defines special requirements (section 1 StandAG): the implementation of the participatory, science-based, transparent, self-questioning and learning procedure poses challenges to all stakeholders of the procedure on the way to the best possible disposal of high-level radioactive waste.

scholarly journals Mineral stability, brine development and rock-fluid reaction at repository-relevant temperatures (<i>T</i> < 200 °C) in the potential host rock rock salt

2021 ◽  
Vol 1 ◽  
pp. 101-102
Author(s):  
Michael Mertineit ◽  
Michael Schramm
Keyword(s):  
Melting Point ◽  
Rock Salt ◽  
Site Selection ◽  
Host Rock ◽  
Mineralogical Composition ◽  
Confining Pressure ◽  
Maximum Temperature ◽  
General Importance ◽  
Host Rocks ◽  
The Impact

Abstract. For a repository of heat generating radioactive waste, the thermal behaviour of the host rock and the impact of temperature increase on rock properties is of general importance. In the German Site Selection Act (2017), the maximum temperature of the container surface is preliminarily limited to 100 ∘C but this limit might change in the future based on scientific and technological findings. Rock salt, as one of the possible host rocks, consists predominantly of halite with varying amounts of accessory minerals (e.g., Hudec and Jackson, 2007); however, some lithological units within a salt deposit, e.g. potash seams, show a different mineralogical composition with high amounts of potash minerals. Most of them are not very stable regarding temperature resistance and stress, contain water in the crystal lattice, and therefore react sensitively to changes in the environment. The melting point of most evaporated minerals is higher than the expected temperatures in a repository but dehydration and partial melting might occur at relevant temperatures, depending on the confining pressure. For example, the temperature of dehydration of carnallite is ca. 80 ∘C at 0.1 MPa confining pressure but increases to ca. 145 ∘C at 10 MPa confining pressure (Kern and Franke, 1986). The melting point of carnallite increases from ca. 145∘C/8MPa to ca. 167∘C/24MPa, which corresponds to a depth of ca. 1000 m. Depending on the mineral paragenesis and composition of saline solutions, different minerals develop with increasing temperature. For instance, a salt rock with an initial composition of kieserite + kainite + carnallite + solution R (25 ∘C) reacts solely to kieserite and solution R, when the temperature increases to 78 ∘C. A rock with a composition of kieserite + carnallite + bischofite + solution Z (25 ∘C) reacts to kieserite + carnallite from 25 to 50 ∘C, from 50 to 73 ∘C only kieserite is stable, and at temperatures >73 ∘C kieserite and bischofite develop (Usdowski and Dietzel, 1998). For the construction of an underground repository, the mineralogical composition of the host rocks and fluids have to be evaluated carefully and play an important role for the site selection and design of the underground facility.

scholarly journals Discrimination among potential activators of the beta-globin CACCC element by correlation of binding and transcriptional properties.

1993 ◽  
Vol 13 (1) ◽  
pp. 44-56 ◽  
Author(s):  
G A Hartzog ◽  
R M Myers
Keyword(s):  
Binding Site ◽  
Site Selection ◽  
Selection Procedure ◽  
Beta Globin ◽  
Binding Studies ◽  
Cis Acting ◽  
Vitro Binding ◽  
Relative Potential

Adult beta-globin-like promoters contain a cis-acting element, CCACACCC, that is conserved across species and is required for wild-type levels of transcription. We have studied the contribution of this element and proteins that interact with it to activate beta-globin transcription. We found that an erythroid-like cell line, MEL, contains several proteins that specifically bind the CACCC element. By comparing the DNA-binding properties of promoters with mutations in the CACCC element with the transcriptional activities of these mutant promoters, we found that two CACCC-binding proteins did not bind to mutant promoters that direct decreased levels of transcription. One of these proteins is the transcriptional activator Sp1, and the other we have designated CACD (CACCC-binding species D). We subjected CACD to a binding site selection procedure and obtained high-affinity CACD binding sites that are identical to that of the beta-globin CACCC element. This result, combined with our finding that CACD binds the CACCC element with a higher affinity than does Sp1, argues that the CACCC element is a target of CACD rather than Sp1. The strategy of correlating the results of a binding site selection experiment with those of in vivo expression and in vitro binding studies may allow evaluation of the relative potential of different proteins to activate transcription through a single cis-acting site.

Selection and Dropping of Whelks By Northwestern Crows

Behaviour ◽  
1978 ◽  
Vol 67 (1-2) ◽  
pp. 134-147 ◽  
Author(s):  
Reto Zach
Keyword(s):  
Site Selection ◽  
Intertidal Zone ◽  
Prey Selection ◽  
Hard Substrate ◽  
Safe Sites ◽  
Corvus Caurinus ◽  
The Mean ◽  
Final Selection

AbstractPrey selection, dropping behaviour and dropping site selection was investigated in Northwestern crows (Corvus caurinus) feeding on whelks (Thais lamellosa). Crows selected only the largest whelks available in the intertidal zone. Although equally palatable, smaller whelks were ignored. Crows assessed size of whelks first by sight and then by weight. Thus, some were picked up with the bill and laid down again before a final selection was made. Rejects were longer and heavier than available whelks and shorter and lighter than selected ones. Usually, crows carried and dropped only one whelk at a time. While dropping, crows typically flew almost vertically up, released the whelk and then dove after it. The mean number of drops required to break a whelk was 4.36. Crows dropped whelks until they could obtain most or all of the soft parts. Usually crows did not give up dropping a whelk until it broke. The mean height of drop was 5.23 m. Crows had a tendency to increase height of drop over successive attempts. During most flights, crows lost some height before releasing a whelk. Presumably, this allowed them to watch whelks fall and bounce. All whelks were dropped onto rock. None were released over water or grass. Crows had specific dropping sites. This was because they selected hard substrate and safe sites for dropping. On dropping sites whelks were unlikely to bounce into water. Results were compared with those of other studies of dropping behaviour in gulls and hawks. Dropping behaviour in crows seems to be much more adaptable than in gulls.

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