Boron dilution in PWR

Since the beginning of the nineties, reactor safety experts have been examining boron dilution i.e. coolant mixing in pressurized water reactors. EnBW has been collaborating in a team of German energy suppliers which has been researching the effects of the previously unknown phenomenon of boron dilution on the safety of German pressurized water reactors. Reactor safety experiments are being supervised and financed at large-scale experimental plants, PKL (primary coolant loop) in Erlangen, and ROCOM (Rossendorf Coolant Mixing Test Facility) in Rossendorf, for this purpose.

Both projects have shown that far less coolant with reduced boron content can collect than was initially thought possible. Theoretical assumptions about mixing have been confirmed. It has been established that all conceivable faults due to boron dilution cannot cause nuclear overheating of the reactor. Although this statement could have been derived from calculations at the beginning, the experiment nevertheless affords additional safety. It was shown that all faults can be brought under control as anticipated even taking into consideration the phenomenon of boron dilution.