KKS identifier: KKS stands for the German Kraftwerk-Kennzeichensystem, which is the power plant identification system. This code is a structured, four-character identifier that designates components within a power plant (or any equipment), starting from the largest system down to the smallest. An example:
That is, the above KKS code hides the protection of the 12th protective pipe for the third pump of the second feedwater system of the first power plant unit.