News about DOPAS Project
DOPAS team met in Eurajoki, Finland
Definition of the design basis and the conceptual designs of plugs and seals to be tested in underground disposal facilities were discussed in Vuojoki, Eurajoki during a DOPAS WP2 meeting in February 2015.
Ten DOPAS partners from 6 European countries participated in the WP2 meeting, which was hosted by Posiva.
One challenge faced by WP2 is to capture the design basis for plugs and seals for radioactive waste disposal programmes that are in different stages of development. The starting point is to define site and host rock characteristics and a conceptual disposal system first and to write illustrative requirements for that site. This helps to convey what is needed for the repository, and to describe how it would be designed and implemented. The safety functions for repository components should be fixed at an early stage of the programme, and used as an input to the development of more detailed designs.
Some waste management organisations, in particular, SKB and Posiva, have well-defined design basis development processes, and the experiences of these organisations can be used as an example on which programme-specific approaches can be developed by others. It was noted in the meeting that it takes many years to develop a requirement management system which is effectively and fully implemented. The design basis is the set of requirements and conditions taken into account in design. Requirements are statements on what the design must be like and what it has to do. For a plug/seal this could be certain strength or a certain hydraulic conductivity. Conditions are the boundary conditions or loads imposed on the design. For a plug/seal this could be the underground environment (dimensions, air temperature, humidity etc.) or controls on the manner in which the design is implemented (e.g. the time available for construction). The design basis for a plug/seal provides the information to the designers to be able to design and construct a plug/seal.
The meeting also discussed compliance strategies that should be adopted for demonstrating plug and seal design compliance with the design basis. These can include, for example, performing full scale tests and conducting performance assessment calculations (using input from small-scale and laboratory-scale tests).
The conclusions from the meeting are one of the inputs to the reporting of WP2. The WP2 summary report will be compiled by SKB and Galson Sciences with support from other DOPAS Partners and published in the beginning of 2016. See more about WP2 Deliverables in http://www.posiva.fi/en/dopas/deliverables.
