B Reactor - Reactor Operation

Reactor Operation

The B Reactor had its first nuclear chain reaction in September, 1944, the D Reactor in December 1944 and the F Reactor in February 1945. The reactor produced plutonium-239 by irradiating uranium-238 with neutrons generated by the nuclear reaction. It was one of three reactors — along with the D and F reactors — built about six miles (10 km) apart on the south bank of the Columbia River. Each reactor had its own auxiliary facilities that included a river pump house, large storage and settling basins, a filtration plant, large motor-driven pumps for delivering water to the face of the pile, and facilities for emergency cooling in case of a power failure.

Emergency shutdown of the reactor, referred to as a SCRAM, was attained either by rapidly fully inserting the vertical safety rods (now called control rods) or, as a backup method, by the injection of borated water into the reactor. In January 1952, the borated water system was replaced by a "Ball-3X" system that injected nickel-plated high-boron steel balls into the channels occupied by the vertical safety rods.

The plutonium for the nuclear bomb used in the Trinity test at Los Alamos in New Mexico and the Fat Man bomb dropped on Nagasaki, Japan was created in the B, D, and F reactors. These first three reactors ran for two decades, and were joined by additional reactors constructed later. The B Reactor was permanently shut down in February 1968.