Abstract: Ion exchangers which reversibly store borate ions in a temperature dependent process are combined with evaporative boric acid recovery apparatus to provide a boron control system for controlling the reactivity of nuclear power plants. A plurality of ion exchangers are operated sequentially to provide varying amounts of boric acid to a nuclear reactor for load follow operations. Evaporative boric acid recovery apparatus is utilized for major changes in the boron concentration within the nuclear reactor.

Abstract: Two sets of ion exchangers or other means which are capable of reversibly storing borate ions are continuously or semi-continuously utilized to provide a nuclear reactor with a supply of both a highly concentrated boric acid solution and a solution having a very low concentration of boron. The process is essentially a timed-two-cycle flow scheme. During the first cycle, fluid is sent from a high concentration storage tank via a cooler and a first set of ion exchanger to a low concentration storage tank while simultaneously sending fluid from a low concentration storage tank via a heater and a second set of ion exchanger to the high concentration storage tank.

Abstract: An ion exchanger which allows flow in both directions along a selected flow-path. A separator plate divides the exchanger tank into two chambers each of which has a flow-conduit so that flow may enter or leave from either chamber while prohibiting the resin particles from migrating from one side of the tank to the other. This ion exchanger permits a dual-directional flow-process to be practiced which results in immediate changes in the boron concentration within a nuclear reactor coolant system even if the ion-exchanger resins have not been completely equilibrated during a previous operation.