Patent Number: 040173585
Section: claims

1. A process for reversibly changing the boric acid concentration in coolant circulated through a nuclear reactor coolant system comprising the steps of: removing coolant having a first concentration of boron therein from the reactor coolant system;  reducing the temperature of the removed coolant to a first lower level;  conveying the reduced temperature coolant in a forward direction through a tank charged with ion exchange resins to remove boron from the resins and thereby increase the concentration of boron in said removed coolant;  returning said removed coolant having increased boron concentration to the reactor coolant system; and thereafter;  again removing and reducing the temperature of coolant from the reactor coolant system to a second level lower than said first level;  conveying the second temperature level coolant in a reverse flow direction through said tank to deposit boron on said resins and thereby decrease the concentration of boron in the second temperature level coolant; and  returning said second temperature level coolant having a decreased concentration of boron therein to the reactor coolant system;  continuing the circulation of said reduced temperature coolant and the second temperature level coolant respectively through the tank until an equilibrium is established between the concentration of boron and the temperature of said coolants.  the second temperature level coolant always flows in the reverse direction through said tank for depositing boron on said resins.  removing coolant having a first concentration of boron therein from the reactor coolant system;  reducing the temperature of the removed coolant to a first lower level;  conveying the reduced temperature coolant in a forward direction through a tank charged with ion exchange resins to remove boron from the resins and thereby increase the concentration of boron in said removed coolant;  discharging said removed coolant having increased boron concentration to a first coolant container; and thereafter;  again removing and reducing the temperature of coolant from the reactor coolant system to a second level  conveying the second temperature level coolant in a reverse flow direction through said tank to deposit boron on said resins and thereby decrease the concentration of boron in the second temperature level coolant; and  discharging said second temperature level coolant having a decreased concentration of boron therein to a second coolant container;  continuing the circulation of said reduced temperature coolant at said reduced temperature level and the second temperature level coolant at said second level temperature respectively, back and forth repeatedly through the ion exchange tank and between said containers to provide coolant having a high concentration of boron in the first coolant container, and coolant having a low concentration of boron in the second coolant container. 2. The process according to claim 1 wherein the reduced temperature coolant always flows into one end of said tank and upwardly over a baffle therein and then down the other side thereof to the outlet on the same side of the tank, thereby removing boron from the resins therein; and 3. A process for reversibly changing the boric acid concentration in coolant circulated through a nuclear reactor coolant system comprising the steps of: