Core response to rapid boron dilution

A rapid boron dilution event in a pressurized water reactor is postulated to occur when two requirements are met. The first requirement is that unborated or diluted water enters the reactor cooling system during a period when there is very little circulation, and the assumption is made that this water collects in a part of the system. The second requirement is that a reactor coolant pump is started so that the slug of relatively diluted water passes rapidly through the core with the potential to cause a power excursion and fuel damage. These events have been studied at Brookhaven National Laboratory from several points of view. Analysis has been carried out to quantify the core damage frequency, to understand the mixing that might occur, and to understand the potential consequences in terms of core damage. This paper presents the results of the neutronics analysis of consequences.