The Isar interim storage facility is integrated in the nuclear power plant site by an outer enclosure. The entire site is protected by a security perimeter fence. This means that CASTOR casks only need to be moved a short distance from the reactor building to the interim storage facility and that no public roads need to be used. A municipal boundary runs through the site and most of the nuclear power plant site belongs to the Municipality of Essenbach. The site of the Isar interim storage facility, however, belongs to the Municipality of Niederaichbach in the District of Landshut, Lower Bavaria Regional Administrative District. The City of Landshut is about 13 km to the south west.
The storage building has a capacity of 152 spaces. The storage building is approximately 92 metres long, 38 metres wide and 18 metres high and consists of two storage areas, one shipment area and an operating area. Storage area 1 covers an area of approximately 1,230 m², storage area 2 approximately 1,330 m².
The Isar interim storage facility will receive reprocessed waste from outside Germany. The concept agreed by the Federal Ministry for the Environment, energy utilities and federal states for the return of vitrified intermediate and high-level radioactive waste from reprocessing in France and the United Kingdom to Germany will ensure that returned casks are fairly distributed to various interim storage facilities throughout Germany. 20 casks from the United Kingdom and 5 from France will be distributed to 4 on-site interim storage facilities: Philippsburg in Baden-Württemberg (five casks containing intermediate-level radioactive waste block canisters), Biblis in Hesse (six casks with high-level radioactive waste block canisters), Brokdorf in Schleswig-Holstein (seven casks with high-level radioactive waste block canisters) and Isar in Bavaria (seven casks with high-level radioactive waste block canisters).
More information about the return of radioactive waste from reprocessing is available here.