the initial concentration of boron in a 10,000-ft3 reactor coolant system is 1700 ppm. a) what volume of solution of concentration 9500 ppm should be added to achieve a new value of 1900 ppm? b) an adjustment of boron content from 1700 to 1600 ppm is made in the reactor. pure water is pumped in, and then mixed coolant and poison are pumped out in two separate steps. for how long should the 500 ft3 /min pump operate in each of the operations?