RSC-Programme - Interim Report. Approach and Basis for - Posiva
RSC-Programme - Interim Report. Approach and Basis for - Posiva
RSC-Programme - Interim Report. Approach and Basis for - Posiva
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31 INTRODUCTIONBackground<strong>Posiva</strong> Oy, jointly owned by Teollisuuden Voima Oyj, Fortum Power <strong>and</strong> Heat Oy, isresponsible <strong>for</strong> implementing the programme <strong>for</strong> geological disposal of spent nuclearfuel in Finl<strong>and</strong>. The programme consists of research, technical design <strong>and</strong> developmentactivities, as well as construction <strong>and</strong> operation of the disposal facility. In 2000,Government made the Decision in Principle (DiP) <strong>for</strong> the disposal of spent fuel fromTVO <strong>and</strong> Fortum's reactors on Olkiluoto Isl<strong>and</strong> in Eurajoki. <strong>Posiva</strong> plans to construct aKBS-3 type repository, designed to be situated at a depth of 400 m to 700 m in thebedrock at Olkiluoto. By decision of the Ministry of Trade <strong>and</strong> Industry (KTM, atpresent Ministry of Employment <strong>and</strong> Economy, TEM) made in 2003, <strong>Posiva</strong> is tosubmit an application to obtain a construction licence <strong>for</strong> the disposal facility by theend of 2012.As the programme is approaching the licensing phase, the Safety Case needs to cover allaspects from design, manufacturing <strong>and</strong> installation to quality control <strong>and</strong> long-termper<strong>for</strong>mance (see e.g. <strong>Posiva</strong> 2008). An aspect emphasised in developmental work, issetting up the requirements <strong>for</strong> design, manufacturing <strong>and</strong> implementation of technicalbarriers. Also aspects related to operation of the facilities need to be considered.Appropriate quality assurance measures need to be developed to verify that therequirements will be met. Consequently, host rock requirements are being developed toguide repository design <strong>and</strong> layout adaptation, as required by the regulator.Olkiluoto siteDuring the past two decades, various investigations have taken place at the Olkiluotosite (see Figure 1-1). Currently, construction of the underground research facilityONKALO provides opportunities to carry out investigations underground. Theseinvestigations enable the collection of more detailed in<strong>for</strong>mation of the rock atrepository depth <strong>and</strong> confirmation of site underst<strong>and</strong>ing obtained during previoussurface-based investigations, as well as making testing <strong>and</strong> demonstration of thedisposal technology possible. Existing site underst<strong>and</strong>ing is summarised in the series ofSite Descriptive Model reports (<strong>Posiva</strong> 2005, Andersson et al. 2007 <strong>and</strong> <strong>Posiva</strong> 2009a)compiled by the Olkiluoto Modelling Task Force (OMTF). Based on this currentunderst<strong>and</strong>ing, the bedrock will generally provide suitable <strong>and</strong> sufficiently stableconditions <strong>for</strong> a repository, although there are certain site specific features, such asextensive de<strong>for</strong>mation zones, volumes of relatively low mechanical strength in relationto rock stress, sparse occurrence of highly transmissive fractures or saline groundwater,which may affect safety of the repository.
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