Patent ID: 8054933

Claim:
An injection system for injecting a chemical solution into a nuclear power reactor while the reactor is in a normal operating condition to treat the reactor's internal surfaces, cracks and crevices with one or more chemical species, and thereby mitigate intergranular stress corrosion cracking, the injection system comprising: a vessel external to the reactor that stores the concentrated chemical solution for mitigating intergranular stress corrosion cracking in the reactor's internal surfaces, first and second valves external to the reactor and connectable to a common transit tube that, in turn, is connectable to the reactor's injection tap through which feedwater enters the reactor, a first injection pump external to the reactor and connected between the vessel and the first valve that pumps the concentrated chemical solution from the vessel through the first valve into the common transit tube connected to the reactor's injection tap, an apparatus external to the reactor and supporting the vessel that measures by gravimetric method the rate at which the concentrated chemical solution is pumped from the vessel by the first injection pump, a source of deionized water external to the reactor, a second injection pump external to the reactor and connected between the source of deionized water and the second valve that pumps the deionized water from the source of said water through the second valve into the common transit tube, to dilute the concentrated chemical solution within the common transit tube before it is injected into the reactor, the first and second injection pumps pumping the concentrated chemical solution and the deionized water, respectively, into the common transit tube, causing the diluted chemical solution to be fed through the reactor's injection tap into the power reactor's internals during normal operation of the power reactor, and a logic controller external to the reactor and connected to the external gravimetric measuring apparatus, the first and second injection pumps and the first and second valves, the logic controller receiving from the external gravimetric measuring apparatus chemical solution weight loss measurements and using the measurements to calculate the rate at which the concentrated chemical solution is pumped from the vessel to control the first and second valves and the first and second injection pumps and thereby control the rate at which the diluted chemical solution is injected into the power reactor, the logic controller injecting the diluted chemical solution into the reactor at a rate whereby the reactor water chemical concentration during application is kept at parts per trillion levels and the conductivity increase is at a level that enhances the convection, eddy and diffusion transport of the injected chemical into the cracks and crevices in the reactor.