No details? In a nutshell, there was water damage which ended up affecting systems that must never be affected by water damage. They lost reactor instrumentation (no sensor readings for several minutes) and control (the control rods were stuck). They ended up flooding the reactor with boric acid, which is a measure of last resort to shut down the reaction, and apparently unheard of in European nuclear power plants.
None of this was reported, although I'm pretty sure reporting it was obligatory. The whole thing was classified as INES Level 1, from a brief look at Wikipedia it sounds more like an INES Level 3 incident.