Forsmark HAW repository

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The Forsmark final repository

by Nils-Axel Mörner

Forsmark in eastern middle Sweden has been chosen as the site for a final deposition of high-level nuclear waste according the KBS-3 method. SKB claims that they can guarantee a long-term safety of this repository for ”at least 100,000 years”. The background for this statement is based on an old concept of exceptional stability of the Fennoscandian bedrock, and multiple barriers in the repository; viz. the canisters, the filling of bentonite around them, the back-fill of shafts and excess tunnels and the bedrock itself.

The stability concept was – in the 1970s when the first decision about the method to use was taken – a reminiscence from an old paradigm held in the 1950s. Within the last 30 years there has been a complete paradigm change when it concerns the so-called stability of the Fennoscandian Shield. We now know (based on solid observational facts) that, during the phase of deglaciation with maximum rate of uplift, the earthquake activity was intensive both in magnitude (with events up to above 8 on the Richter-scale) and frequency (with 7 events recorded within 102 varve-years in the Stockholm region). The bedrock fractured over large distances (invalidating the safety distance used by SKB between regional fault and fracture zones and the proposed deposition of the canisters). A serious addition process recently documented at several sites is explosive methane venting at the transition from methane ice stored in bedrock voids to methane gas (at a volume ratio of 1:168). All these novel facts invalidate the claims of a full safety remaining over “at least 100,000 years”.

The Forsmark area does certainly not represent “the best area in Sweden” for a final KBS-3 repository. Geologically, it represents a major tectonic shear zone; i.e. an environment that one should rather avoid. The direct connection with the Baltic is another deeply negative factor (in anything goes wrong, a maximum spreading will occur via the Baltic). Therefore, a KBS-3 repository at Forsmark offers no trustworthy solution; rather the opposite.