1. Context

The development of ordinary boiling water (BWW) nuclear reactors in Germany has led to major innovations almost from the outset. In 1968, for example, the Lingen reactor was equipped with the world's first finely tuned rod control mechanism. At the time, Brunsbüttel was the first reactor in the world to have its core cooling water recirculation pumps installed in the reactor vessel, and the two units, B and C, of the German Gundremmingen power plant, which began commercial operation in 1984-1985, already had the features of an advanced BWR: fine-tuning rod drive mechanisms, integrated recirculation pumps, residual power extraction (RHR) in one to three independent trains, and cylindrical pre-stressed concrete containment with steel sealing skin. The most significant of these innovations were subsequently adopted by all BWR plant builders.

The next stage in the development...