Patent ID: 6944254
Filing Date: 2005-09-13
Classification: G21C,Y02E

Abstract:
1. A shutdown method for a pressurized water reactor (PWR) following interruption of power operation, the PWR having a reactor coolant system (RCS) including a reactor pressure vessel (RPV) containing fuel assemblies, comprising the steps of: cooling reactor coolant containing dissolved hydrogen in the RCS; adding boron to the reactor coolant in the RCS; adding a decontamination reagent into the boron-containing reactor coolant, the decontamination reagent including a reducing agent to reduce iron and nickel in the RCS and a chelant to complex the iron and nickel; circulating the reactor coolant containing the decontamination reagent through the RCS, including through the RPV containing the fuel assemblies, to dissolve and complex the iron and nickel; removing complexed iron and nickel from the reactor coolant; while circulating the reactor coolant containing the decontamination reagent through the RCS to dissolve and complex the iron and nickel, degassing the RCS to remove hydrogen gas and then adding an oxidant to oxidize residual dissolved hydrogen and decontamination reagent in the reactor coolant; and reducing gamma emitting activity of the reactor coolant.