Biblis A was shut down on 18 April 2003. According to the Federal Ministry for the Environment, it will not be restarted, due to "safety faults of grave significance".
Following some repair work, it was discovered that the prime opening of the emergency coolant pumps were only 5.9m2 in cross section, while the German reactor safety codes require them to be at least 7.3m2. The actual effective prime opening cross section was just 3m2, due to the cross section of the filter construction. The TÜV concluded that sufficient cooling of the core during an accident could not be guaranteed.
It has not yet been determined whether the fault has existed from 1974, when the plant was first commissioned, or whether it resulted from later installations of horizontal pipes.
RWE said that the actual cross section of the filter was 4.8m2, and that the fault could be eliminated by relatively simple technical measures. These measures consist of opening two inspection manholes which were fitted with additional filters. This measure would provide a free cross section of nearly 10m2.