down period and following degasification of hydrogen which permits a build up of radiolytically produced hydrogen peroxide however only a small amount of cobalt 58 is released thus establishing the need for injection of an oxygen bearing substance into the coolant to accelerate the release activity the most suitable time for addition of the hydrogen peroxide to achieve oxygenation of the coolant is immediately after the cool down has proceeded to a system temperature of u02dc 140 u00b0 f and with the system depressurized and completely filled with a solid mass of water the system is thereupon repressurized to 400 psig to permit immediate circulation of the hydrogen peroxide upon its addition by the reactor coolant pumps after the system is repressurized the hydrogen peroxide is introduced into the chemical addition tanks from which it is pumped to the reactor primary loop when the additions from the chemical addition tank are pumped into the charging pump suction the charging header flow should be 90 100 gpm 342 380 liters per minute to further dilute the hydrogen peroxide solution before it enters the reactor primary loop the residual concentration of hydrogen peroxide in the coolant to achieve the solubilization of susceptible nickel sources is about 2 ppm for a standard three loop plant having a volume of 9160 cubic feet or 2 59 u00d7 10 5 liters 520 grams of.