CHRISTA III (safety and verification concept)
Country / Region: Deutschland
Begin of project: January 1, 2023
End of project: October 31, 2025
Status of project: October 1, 2024
According to the Repository Site Selection Act (StandAG), the host rocks rock salt, clay rock and crystalline rock (such as granite) in Germany that are potentially suitable for the final disposal of high radioactive waste must be taken into account in the process. A repository for high radioactive waste must fulfil numerous safety requirements. In the CHRISTA project, BGE TECHNOLOGY GmbH (BGE TEC), the Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) and the Federal Institute for Geosciences and Natural Resources (BGR) are investigating what such a safety concept for crystalline rock could look like. The CHRISTA-III project is concerned with developing a methodology for the systematic derivation of expected and deviating developments in crystalline rock in Germany and its exemplary application as a basis for evaluating safe containment, taking optimisation measures into account.
Fig. 1: Options for storage in crystalline rock
Source: Jobmann et al. (2021)
Focus of the CHRISTA-III project:
- Derivation and evaluation of developments of the repository system required for the safety assessment according to § 3 of the German Repository Safety Requirements Ordinance (EndlSiAnfV) for a generic site in crystalline rock according to the repository concept mKBS-3.
- Further development of a modelling concept for the THM behaviour of the crystalline rock to analyse the safety functions and the integrity of the geological barrier.
- Evaluation of uncertainties and optimisation options to strengthen the robustness of the repository system in accordance with § 11 and § 12 of the Repository Safety Requirements Ordinance (EndlSiAnfV).
Resulting questions for CHRISTA-III:
- Which expected and deviating developments must be taken into account for a repository in crystalline rock?
- What role does the cask failure in a mKBS-3 concept play in the derivation of the developments?
- Based on the results from CHRISTA-II, the question arises as to whether a combination of different essential barriers can increase the robustness of the repository system and, if so, to what extent this happens?
- Which near-field processes are essential for different emplacement options?
- What influence does the fracture distribution have on the assessment of uncertainties and the hydraulic properties of the repository system?
- What options are there for optimising the repository system?
Work programme CHRISTA-III:
- WP 1: Methodology for deriving developments for repository systems whose safety is based on technical and geotechnical barriers (lead BGETEC)
- WP 2: Combination of previous emplacement options (lead GRS)
- WP 3: Further development of a modelling concept for analysing the integrity of an isolating rock zone in crystalline rock in connection with the combination of emplacement options (lead BGR)
- WP 4: Optimisation options in the repository system (lead BGETEC)
WP 5: Documentation (lead BGETEC)
Literature:
Jobmann, M., Burlaka, V., Flügge, J., Frank, T., Frenzel, B., Hassanzadegan, A., Johnen, M., Krumbholz, M., León Vargas, R.P., Lommerzheim, A., Maßmann, J., Mayer, K.-M., Meleshyn, A., Guevara Morel, C., Mrugalla, S., Müller, C., Noseck, U., Rübel, A., Simo, E., Sönnke, J., Stark, L., Thiedau, J., Weihmann, S., Weitkamp, A. & Wolf, J. (2021): CHRISTA-II - Methodisches Vorgehen zur sicherheitlichen Bewertung von Endlagersystemen im Kristallin in Deutschland. BGE TEC, GRS, BGR, Synthesebericht, BGE TEC 2021-17: 119 S.; Peine.