The B Reactor and the Plutonium That Destroyed Nagasaki

In the summer of nineteen forty-three, thousands of construction workers arrived at a remote bend of the Columbia River in southeastern Washington and were told almost nothing about what they were building. The site was called Hanford. The project had a number. The workers had clearances. Most of them did not have answers.

What they built was the B Reactor: the world's first full-scale nuclear fission reactor, completed in September of nineteen forty-four. It was the size of a six-story building, encased in concrete and graphite, cooled by Columbia River water pumped through more than two thousand aluminum tubes. Physicist Enrico Fermi came out from Chicago to supervise its startup. On September twenty-sixth, nineteen forty-four, the B Reactor went critical for the first time.

What it produced was plutonium. Not the small experimental quantities that the Manhattan Project's Chicago Pile reactor had generated, but industrial quantities, kilograms at a time, the material that the project needed to build a bomb. The plutonium manufactured at Hanford was transported in specially shielded containers to Los Alamos, New Mexico, machined into a sphere, and assembled inside a weapon called Fat Man. On August ninth, nineteen forty-five, that weapon was dropped on the Japanese city of Nagasaki. Between sixty thousand and eighty thousand people died, by the National Park Service's documented range. Many died immediately. Others died over weeks and months from radiation exposure.

The surrounding communities, the towns of Richland and Kennewick and Pasco, did not know what had been made in their neighborhood until they heard the radio announcement after Hiroshima. Richland's high school sports teams adopted the mushroom cloud as their mascot.

The B Reactor operated until nineteen sixty-eight. It was designated a National Historic Landmark in two thousand eight and is now open to limited public tours as a unit of the Manhattan Project National Historical Park. Visitors walk through the graphite face of the reactor, see the control rods still in place, and stand in the rooms where the plutonium production was managed by technicians who understood their instruments but not always the full scale of what those instruments were making.