The first underground radioactive waste repository (NRWR) in Hungary is located near the village of Bátaapáti in the Mórágy Granite Formation. The repository serves as the final storage of the low and intermediate level radioactive wastes (LILW) resulting from the operation of Paks Nuclear Power Plant (NPP). The present paper discusses the stability issue of the tunnel face, including investigation of the Western Exploratory Tunnel (WET) of the NRWR. The face stability has been analyzed assuming that the WET crosses a fault-zone, which dominantly consists of weak, highly fractured rock mass. There is no well-known method to calculate tunnel stability of tunnel face during penetration of a fractured zone. The relevance of the hand calculation was verified with the 3D finite difference model, where the exact tunnel geometry, face support and fracture zone is directly considered. The calculations were performed without reinforcement as well, in order to show the efficiency of the support. Furthermore, the effect of groundwater pressure on the tunnel face has been also assessed by conducting all analysis.
1 National Radioactive Waste Repository Project in Bátaapáti
The Paks Nuclear Power Plant (Hungarian: Paksi Atomerőmű), is the first and only operating nuclear power plant in Hungary. The establishment of the NPP had presented new problems concerning the management of radioactive waste. The temporary storage problem of low- and intermediate level waste were resolved by the Püspökszilágy radioactive Waste Treatment and Disposal Facility (RWTDF) until 2005 when the 5040 m3 capacity was not adequate. There were many geological investigations carried out between 1997-1999 and 2002-2003 in order to be able to decide where to host the new long- term disposal of low- and intermediate level waste from Paks. In mid- 2005, after considering the economic, environmental and technical aspects the village of Bátaapáti was chosen as the potential location. The project has been financed by RHK Ltd. (Public Limited Company for Radioactive Waste Management) (Kovacs et al. 2012).