This is the monthly report for the Hanford Laboratories Operation, April, 1959. Reactor fuels, chemistry, dosimetry, separation processes, reactor technology financial activities. Biology operation, physics and instrumentation research, employee relations, operations research and synthesis operation programming, radiation protection, and laboratory auxiliaries operation are discussed.

Chemical control of the SM-2 was evaluated both as a partial substitute for burnable poison in the fuel element meat and as a means of improving plant performance. Based on a review of existing information, boric acid was chosen as the reference soluble poison. It was shown that 60% of the burnable B/sup 10/ in the fuel element matrix could be replaced by soluble B/sup 10/ in the coolant without impairing plant stability during load transients. The feasibility of improving power distribution and reducing the number of control rods by supplementing the burnable poison with chemical control was also demonstrated. A preliminary design of an injection and removal system was prepared for the SM-2. (auth)