Prototype Repository Project

For the Prototype Repository Project, six different geometries were considered in a preliminary thermo-mechanical analysis. Figure 1 shows the basic characteristics of those models. The case (6) corresponds to the actual geometry, assuming only a plane of symmetry. The rest of the geometries involve additional symmetries that are not strictly correct. The external boundaries were defined far away from the test, as usual in finite element computations. The effect of boundaries was particularly important for the thermal problem, the mechanical aspects being almost irrelevant in these cases. 

Persson, G. Broman, O. 2000. Prototype Repository. Project Plan FlKW-CT-2000-0ci055. Aspo Hard Rock Laboratory. International Progress Report, IPR-00-31. SKB, Sweden. 

The pebble bed high temperature reactor THTR 300 was shutdown on 01.09.89 after more than 16,000 h in operation. The THTR 300 is a prototype reactor project that is jointly sponsored by the Federal Republic of Germany, the state North l ine Westphalia and the operator Hochtemperatur-Kemkraftwerk GmbH (HKG). The public financiers of this prototype reactor and the operator could not solve the financial problems for continued operation of this technically intact plant. The decommissioning decision had not been expected at the time by the operator. This is why safe enclosure the German term for SAFSTOR turned out to be the only technical solution for quick decommissioning of the plant, apart from financial reasons and the non availability of a final repository. The plant is intended to be dismantled after about thirty years of safe enclosure, provided respective funds are available. The decommissioning was done in three steps that were mostly scheduled one after the other (FIG. 1), III. 

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