The MPRR complex encompasses several buildings. Step by step, buildings that were no longer needed were cleared, decontaminated and – after a clearance measurement and release from the requirements of the German Atomic Energy Act – demolished.
The spent fuel storage facility contained the spent fuel pools and was demolished in early 2013. For structural reasons, parts of the walls to the neighbouring reactor building had to remain in place.
When the reactor was in operation, the auxiliary building contained several waste water containers, a workshop and storage and assembly areas. It was demolished in the first half of 2015.
The MPRR’s reactor pressure vessel was disassembled from 1999 to 2008. As a result, over 99 % of the radioactive inventory that remained in the facility after the end of operation was removed. The reactor had a total mass of roughly 400 t, a height of 7.60 m and a diameter of 4.60 m. The reactor could only be disassembled on a remote basis, at its original installation site. The vessel cover was removed, taken apart and packed remotely. The vessel was flooded so that the highly activated assemblies could be taken apart underwater. For one thing, water acts as a good shield against radioactivity, and for another, particles that were released during the dismantling process were bound in the water. Upon completion of the work, the water was removed for disposal. The thermal insulation was removed from the empty reactor pressure vessel and openings for lifting were cut using oxyacetylene. It was then possible to raise the pressure vessel with a mass of approx. 100 t and to fix it within a rotating ring. The flange of the pressure vessel was detached and sawn into transportable sections on a workbench using a bandsaw. The pressure vessel itself was taken apart using a flame cutter.
Thanks to the progress that had been made with dismantling, the exhaust stack, which is still needed for the building’s ventilation systems, could be shortened in late 2009. The guy wires were no longer needed, and their foundations were removed in November 2015. This saves on maintenance costs.
Disassembly of the biological shield began in 2010. As this annular concrete mantle acted as a shield against gamma and neutron radiation from the reactor, it became radioactive on the inside during operation and is additionally contaminated with tritium. Roughly 370 tons of radioactive iron-reinforced heavy concrete needed to be disassembled on a remote basis.