RD&D-Programme 2004 - SKB

A4.5 Safety assessment
The integrated planning for safety assessments during the site investigation phase is described
in section A2.3.3. Figure 10 shows in greater detail the links between safety assessment, the
versions of site descriptions produced by the investigations, and corresponding repository
layouts from design.
Preliminary safety evaluations for the investigated sites are planned as a first step. For
Oskarshamn, this means separate evaluations for the Simpevarp and Laxemar areas. In all
cases (Forsmark, Simpevarp and Laxemar), the site-specific background material for the safety
evaluations consists of site-descriptive models, version 1.2. The main purpose of the safety
evaluations at this relative early stage of the site investigations is to determine whether the early
judgements of the sites as being suitable with respect to long-term safety still hold, taking into
account the borehole data from repository depth that will be available. If the results suggest
difficulties meeting the safety requirements, the investigations of the site in question may be
discontinued. Furthermore, the work is expected to provide valuable feedback to the planning
of the continued investigations and to future safety assessments, mainly SR-Can.
The safety report SR-Site will be based on the total body of material that is available when
the site investigations with associated design work are finished. SR-Site will show whether the
entire system with encapsulation according to the described technology and deep disposal on the
site that is ultimately chosen satisfies the regulatory requirements regarding long-term safety.
The planning for SR-Site is still at an early stage. The intention is to perform safety assessments
for two sites, with equivalent deep repository solutions. Other details of the implementation
will depend on the ongoing process of determining the methodology for the site investigation
phase’s safety assessments, experience from the preliminary safety evaluations and SR-Can,
and the outcome of the remaining site investigations.
A4.6 Evaluation and site selection
The ongoing site investigation phase concludes the siting process for the deep repository that
has been going on since the beginning of the 1990s. Since the start, the guiding principles for
the siting work have been:
• The repository shall be located in crystalline basement on Swedish territory.
• It must be possible to satisfy environmental, safety and radiation protection requirements.
• Active siting studies are only conducted in municipalities that have good geological and
technical conditions and that wish to participate in the siting work.
These principles are based on knowledge gained from study site investigations, general siting
studies and safety assessments which SKB has conducted since the late 1970s. One main
conclusion from the studies is that there may be sites in many of Sweden’s municipalities that
satisfy the requirements for a deep repository.
After feasibility studies in eight municipalities, an integrated evaluation of all the findings was
made in 2000. On the basis of this evaluation, SKB prioritized areas in Oskarshamn, Tierp and
Östhammar for site investigations and proposed further investigations of the siting prospects
in Nyköping Municipality. The facts and evaluations on which SKB based these choices
were presented in detail in the so-called RD&D-K report. In the subsequent decision process,
the Government gave the go-ahead to SKB’s proposals. After approval by the concerned
municipalities, site investigations were commenced in Östhammar (Forsmark) and Oskarshamn
(Simpevarp area), while Tierp and Nyköping declined further participation in the siting process.
398 RD&D-Programme 2004