atw 2018-05v6

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<strong>atw</strong> Vol. 63 (<strong>2018</strong>) | Issue 5 ı May DECOMMISSIONING AND WASTE MANAGEMENT 318 | | Fig. 4. Modules of the Bethoven calculation tool. | | Fig. 5. Logo of the calculation tool “Bethoven”. provided with instructions, in which the required evidence for the repository documentation are described. The acronym for the calculation tool for holistic waste management is Bethoven according to Figure 5. 4 Validation and discussion Extrapolations have been realized according to the optimisation parameters repository volume, container costs, loading time and volume utilization of the last container. The validation of the calculation tool was based on existing final storage containers with complete and certified final disposal documentation and certified suitable for disposal, e. g. [4] and [5] as well as on raw waste data from national disposal program (NaPro) [6]. The validation of the calculation tool has been successful and the extrapolations give meaningful results that illustrate the potential of optimising packaging planning. The input data can be taken from the planning of dismantling and material analysis as single data or from software like waste flow tracking and product control system (AVK) or the residue-tracking control program (ReVK). The data of a loaded final storage container can also be the data input for Bethoven to create the waste data sheet. In the mentioned order, the number of data is decreasing. Bethoven also can be used to estimate number and type of necessary containers to pack a certain amount of waste according to an optimisation parameter. Another function of the calculation tool is to give a statement about the general packability of waste according to the Konrad disposal conditions and handling possibilities at the site. For detail planning and optimisation the Bethoven calculation tool can give specifications like costs and exposure time for the executive staff. As highest level of detail, the tool is able to check the packability of waste with respect to a particular container. For that the calculation tool gives a list including the parameters for the package variant according to the Konrad disposal conditions and a waste data sheet. An overview about these classifications is given in Figure 6. The validation of Bethoven demonstrates the range of possibilities for optimisation of packaging by using a calculation tool for packaging planning. For individual waste packages, the calculation tool is able to generate a detailed waste data sheet. For locations with small amounts of radioactive waste, optimising the volume utilization of the last container is expedient and for large amounts of waste. Bethoven can be used to optimise the packaging according to disposal volume, loading time or container costs. 5 Summary and outlook Optimisation of packing radioactive waste is necessary with regard to the volume limit of the repository and the exposure times for the executive staff. For the development of the calculation tool, the planning of waste management for radioactive waste | | Fig. 6. Input and output for raw, product and container data. Decommissioning and Waste Management Optimal Holistic Disposal Planning – Development of a Calculation Tool – ı Johannes Schubert, Anton Philipp Anthofer and Max Schreier

<strong>atw</strong> Vol. 63 (<strong>2018</strong>) | Issue 5 ı May with negligible heat generation has been considered from the generation of waste through the conditioning and packaging of the various waste streams according to the Konrad disposal conditions to the final disposal documentation. The developed calculation tool considers the change of the waste properties by the respective conditioning procedures and determines the optimal variant for a container loading according to the selected parameter. The restrictions regarding radiology, volume, mass, conditioning processes and available technical facilities at the site are taken into account and inadmissible loading variants are excluded by the calculation tool. The calculation tool is based on a modular structure. By using the different input data, Bethoven creates an overview about the needed information to the determined optimal packaging variant and a waste data sheet according to the Konrad disposal conditions. The calculation tool has been validated on the basis of data from already conditioned repository containers. Furthermore extrapolations were made for raw waste on the basis of data from NaPro. The validation demonstrates the range of possibilities for optimisation by using a calculation tool for packaging planning. With different level of detail, the calculation tool can be used to optimise the packaging process. Perspective, the calculation tool is to be supplemented with established planning and calculation tools for dismantling, handling, logistics and material flows. This coupling establishes the calculation tool for using at holistic disposal planning for the decommissioning activities of nuclear facilities and guarantees the optimal utilization of the resources like time, exposure time for the executive staff, costs and available volume of the Konrad repository. References [1] Anthofer, A.; Schubert, J.: Repository Documentation Rethought. ATW, Vol. 62 (2017), Issue 11, November. Page 649-653. [2] Arbeitskreis Abfallmanagement des VGB PowerTech e.V.: Entsorgung von Kernkraftwerken: Eine technisch gelöste Aufgabe. Essen, 2011. [3] Bundesamt für Strahlenschutz: Anforderungen an endzulagernde radioaktive Abfälle (Endlagerungsbedingungen). Endlager Konrad, Fachbereich Sicherheit nuklearer Entsorgung. Stand: Dezember 2014. Salzgitter, 2014. [4] Baumann, R.: Nachweis der Endlagerfähigkeit von radioaktiven Abfallgebinden, die nach den (vorläufigen) Konrad-Endlagerungsbedingungen (Dez. 1995) hergestellt wurden. Siemens AG, Symposium Endlagerung radioaktiver Abfälle. Oktober 2014. [5] Karbstein, L.; Anthofer, A.; Borchardt, R.; Reithmeier, H.: Konradgerechte Konditionierung der ANTARES-Shutterbaugruppe aus dem FRM II; Kontec 17; Dresden, 2017. [6] Bundesministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit: Verzeichnis radioaktiver Abfälle, Bestand zum 31. Dezember 2013 und Prognose. Authors Dipl.-Ing. Johannes Schubert Dr.-Ing. Anton Philipp Anthofer Dipl.-Ing. Max Schreier VPC GmbH Fritz-Reuter-Straße 32c 01097 Dresden, Germany DECOMMISSIONING AND WASTE MANAGEMENT 319 Scope for Thermal Dimensioning of Disposal Facilities for High-level Radioactive Waste and Spent Fuel Joachim Heierli, Helmut Hirsch, Bruno Baltes Introduction The objective of final disposal of high-level radioactive waste in deep geological formations is to isolate the radionuclides from the accessible biosphere for a sufficient period of time [IAEA 2011; IAEA 2012]. To achieve this, both the functionality and the integrity of the disposal system must be assured under ambient conditions that depend both on the geological environment and on engineering choices taken in the planning of the facility. In particular, the amplitude of the transient temperature increase caused by the release of nuclear decay heat in the disposal area is scalable through design strategies and thermal dimensioning. The trade-offs between hotter and cooler repository designs are multiple and complex [Whipple et al. 1999]. In many ways, the ambient temperature influences the physical processes taking place in and around the repository. For example, hotter designs delay liquid water contact with corrodible barrier materials and, with it, liquid-phase oxidation-reduction reactions. In some environments, they cause faster convergence of circumambient rock [Mönig et al. 2013] or tend to eliminate the excavation damage zone as a possible by-pass for radionuclides to escape [Beswick et al. 2014]. On the other hand, cooler designs decrease the rates of thermally activated diffusion-reaction processes, induce smaller changes to the natural system, alleviate pore or crack water pressures in the circumambient rock [Gens et al., 2017; Wieczorek 2017] and are likely easier to analyse [Whipple et al. 1999]. In geologic repositories relying on the barrier properties of smectite-rich materials such as argillaceous rock or bentonite, increased peak temperatures in the hydro-chemical environment raise the difficulties of substantiating the safety case with a satisfactory level confidence [Heierli 2016; Huang et al. 1993]. Pertaining to operational aspects, high temperatures produce adverse working conditions for human or machine operated underground activities. For example, the retrievability of waste, either limited or Decommissioning and Waste Management Scope for Thermal Dimensioning of Disposal Facilities for High-level Radioactive Waste and Spent Fuel ı Joachim Heierli, Helmut Hirsch, Bruno Baltes