Exhibition research display object 12: Granite

This piece of granite is from the Bátaapáti repository, whose chambers are carved into the 340 to 350-million-year-old Mórágy granite complex located on the southeastern edge of the Mecsek Mountains. Granite is one of three geological materials currently considered suitable for safely sealing radioactive waste from the environment long enough for the radioactive material to decay to levels comparable to unenriched, naturally occuring uranium ore. For low- and medium-level waste, this means around 600 years, while spent nuclear fuel demands a much longer timeframe—over 10,000 years for the period of primary concern, with some by-products remaining radioactive for millions of years. Granite’s unique properties make it an excellent candidate for this task. Its crystalline structure allows for self-sealing mechanisms, effectively keeping fluids away and thus preventing the migration of radioactive materials across geological timescales. Notably, granite is also the host rock for Onkalo in Finland, the world’s first final repository for spent nuclear fuel, situated 400 meters underground. The exhibition also features works exploring the other two materials considered suitable for radioactive waste storage. The ceramic objects by Rita Süveges and Csilla Nagy delve into the potential of the Boda Claystone Formation as a host for high-level radioactive waste, while salt from the old salt mines in Morsleben, repurposed for low- and medium-level waste storage, is the starting point of Sonya Schönberger’s work.

According to current research, Bátaapáti’s granite formation originated in the southern part of the Congo Basin. It traveled thousands of kilometers in a molten state into the depths of the Earth, eventually cooling and solidifying before rising to its present location near the surface. The geological formation is 200 kilometers long and 30 kilometers wide. At a depth of 250 meters, it houses a 600-meter-long chamber waste storage system meant to accommodate all low- and medium-level nuclear waste generated by the Paks Nuclear Power Plant until 2084, when the decommissioning phase of its four reactor blocks will end according to current planning. It also hosts waste produced by various other industries. Primarily composed of mildly contaminated materials such as protective clothing and tools, it is stored in steel barrels, stacked in concrete containers, which are then precisely arranged and sealed with liquid concrete to ensure safety. Given the plans to expand the Paks NPP, this timeline and the storage’s capacity might require adjustments, though PURAM (the Public Limited Company for Radioactive Waste Management) remains confident about the long-term capacity and suitability of Bátaapáti’s granite formation to meet Hungary’s nuclear waste management needs.