With the Sub-areas Interim Report, the Bundesgesellschaft für Endlagerung (BGE) has reduced the blank map of potential repository sites in Germany to about half of the country. The second step of Phase I is now about moving from 90 sub-areas to a significantly reduced number of siting regions with a manageable area. At the end of this phase, the BGE will propose these siting regions as locations for surface exploration. In this step, i.e. Step 2 of Phase I, the BGE will narrow down its search from 54% of the national territory to some 10, 20 or 30 siting regions with the help of multiple instruments: representative preliminary safety analyses, geoscientific consideration criteria and, in some circumstances, theoretical planning weighing criteria. Here, the underlying data is the same as in Step 1: the BGE continues to evaluate the data relating to the subsurface geology that it was provided with in Step 1, in particular by the state geological services. It is not until Phase II that it will collect its own data by means of boreholes or seismic surveys.
The first step is to carry out the initial safety assessment of possible repository sites, i.e. the representative preliminary safety analyses. The BGE is presenting an initial methodological proposal for carrying out these preliminary safety analyses and putting this proposal forward for discussion. By doing so, it hopes to ensure that the methodology for further narrowing down the areas is known before the actual work begins. Over the coming weeks, the BGE will put the methodological approach forward for discussion and is open to suggested improvements or modifications. After all, the ultimate aim is to identify a methodology for designating the regions with good geological and technical suitability for further exploration.
How does the BGE intend to assess safety?
processing. To this end, the sub-areas will be divided into “investigation areas” – and, because these areas must cover the sub-areas completely, as stipulated by the Repository Safety Investigation Ordinance (EndlSiUntV), the BGE will designate an independent investigation area for each individual sub-area.
With regard to the 60 salt domes that are still being considered as part of the procedure, this is also a sensible division in terms of the size of the areas. In large sub-areas with flat-lying rock salt deposits, in clay rock or in crystalline host rock, however, it will not be sufficient to designate one investigation area for processing and safety assessment. The BGE will divide these investigation areas into investigation sub-areas, with the common feature being that the considered investigation sub-areas have homogeneous rock formations or that other geoscientific considerations favour their processing in this manner. However, it may also be the case that these investigation sub-areas are subdivided into further areas as part of this work, for example if a minimum requirement is not met or an exclusion criteria applies in part of the area. Processing then ends for this affected area only, and the rest of the investigation sub-area can undergo further investigation.
Only the best candidates go forward
Several assessment steps are carried out in order to systematically review all investigation areas and investigation sub-areas with regard to their potential suitability for the designation of a “containment-providing rock zone”. Here, areas can fail to meet the exclusion criteria or minimum requirements, which are reviewed on an ongoing basis throughout the representative preliminary safety analyses, because new insights are constantly being gained from existing or newly acquired data. These areas are assigned to Category D. In other words, they receive a bad report and are not suitable for final disposal. Processing of these areas ends at this point.
Areas that have cleared this hurdle undergo further examination in order to determine whether a containment-providing rock zone can be designated within an area – and how safe this zone might be. If unfavourable circumstances are identified, e.g. if an aquifer is located very close to the possible emplacement site, this is not an ideal situation. An area is assigned to Category C if the BGE can say for certain that the area will not be the site that provides the best possible safety. These areas then also receive their reports and are excluded from further consideration.
If areas clear these hurdles, they undergo further examination. Those areas that pass all of the assessment steps are assigned to Category A and then move on to the next assessment step: the renewed application of the geoscientific consideration criteria. Areas are assigned to Category B if they have only performed badly or worse than other areas in one assessment step or if it is not
yet possible to assess them because there is still insufficient information available. The experts then enter into a safety-related discussion regarding these areas, in which all relevant information is once again comparatively evaluated and collated. If there are sufficient indications that the area could become a Category A area as a result of exploration in Phase II, i.e. due to an improvement in the knowledge base, then it is set aside for the time being but remains under consideration. Areas remain in Category B if this approach identifies them as promising candidates by comparison with areas with a better information base. If areas perform justifiably worse in comparison with areas with a better information basis, processing ends and the areas become Category C areas. If no answer can be found to the question, the BGE makes a proposal regarding the areas with insufficient underlying data in addition to the proposal regarding the siting regions.
The documents – an abridged version for readers in a hurry, a technical abridged version of the method, which can be consulted online, and an annex containing the method derivation and details of the example applications – will be available on the BGE website from 28 March 2022 onwards: www.bge.de/methodik
How will the method be discussed?
From 28 March to 1 April 2022, the BGE will present the method for carrying out the representative preliminary safety analyses. The main event will be held as a virtual event. from 6:00 p.m. to 8:00 p.m. on Tuesday, 29 March 2022. However, the BGE will begin the process on Monday with a hybrid event in Winsen an der Luhe, a town south of Hamburg. In addition to the methodology, this event will also address the methodological approaches that the BGE already tested during the exploration of the Bahlburg salt dome (sub-area 035_00) and what it learned about the sub-area in the process. The events from 30 March to 1 April 2022 will also focus on the “areas for methodological development” – Thüringer Becken (30 March 2022), Saxothuringikum (31 March 2022) and Opalinuston (1 April 2022). You can find details of the events here: series of events on methodological development.
The BGE’s online consultation forum will be activated on 29 March 2022:
www.forum-bge.de
After a one-off registration process, participants will be able to pick a name – which needn’t be their real name – and to open discussion threads, which can then be taken up by other parties to the consultation. Where possible, the BGE will answer questions within the consultation period. The speed of the response will vary depending on the complexity of the questions – but a response will definitely be provided. The forum will also serve as a platform for putting the abridged version of the methodology for the representative preliminary safety analyses forward for discussion. Those who wish to submit expert opinions will be able to do so by writing to dialog(at)bge.de. The consultation period ends on 31 May 2022.
On 27 June 2022, the BGE will hold another event to provide information on the course of the public discussion regarding the method and will report on how it intends to proceed with the received proposals in order to further improve the methodology. Likewise, the first Forum Endlagersuche (20/21 May 2022) will also be held as part of this consultation period and will address the methodology for the representative preliminary safety analyses.
About the BGE
The BGE is a federally owned company within the portfolio of the Federal Environment Ministry. On 25 April 2017, the BGE assumed responsibility from the Federal Office for Radiation Protection as the operator of the Asse II mine and the Konrad and Morsleben repositories. Its other tasks include searching for a repository site for the disposal of high-level radioactive waste produced in Germany on the basis of the Repository Site Selection Act, which entered into force in May 2017. The managing directors are Stefan Studt (Chair), Steffen Kanitz (Deputy Chair) and Dr Thomas Lautsch (Technical Managing Director).
