RD&D-Programme 2004 - SKB

4.7 Design of the deep repository
The current reference design of the deep repository is based on generic data on Swedish bedrock
at a depth of 400–700 metres. The layout is general and will now be adapted to conditions on
the sites in the municipalities of Oskarshamn and Östhammar where site investigations are
being conducted. In the continued work we will study how different repository designs and
different buffer and backfill materials affect safety and the external environment on the sites to
be investigated.
The barriers can also be given different dimensions, and deposition depth and layout can vary.
SKB wishes to preserve freedom of choice for as long as possible, since this provides greater
flexibility and makes it possible to make use of the latest technical and scientific advances. The
design work is being pursued stepwise in accordance with a model developed for the nuclear
power plants and SKB’s existing facilities Clab and SFR. The design process is based on the
above-mentioned technology development and is being coordinated with the results from the
site investigations, the EIA work and the safety assessments and system analyses. The programme
for design is presented in its entirety in Chapter 11.
4.8 Long-term observations
The deep repository will be designed so that it is safe even without monitoring or maintenance.
However, this requires long-term observations and measurements to gain a better scientific
understanding of the site and the repository. With this in mind, SKB has drawn up guidelines
for conducting long-term observations during the site investigation, construction and operating
phases. Requirements on fissile material controls (safeguards) and on physical protection of
such materials are tough. Work is being pursued internationally to define the requirements on
the post-closure safeguards system for a closed geological repository. When SKB designs the
deep repository, we will do so with a view towards the requirements and viewpoints of the
supervisory authorities as regards safeguards and physical protection. Chapter 12 deals with
long-term observations and monitoring.
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