Machinery is painted a minty green, and there are handwritten signs labeling parts of the reactor. There’s about two hours to explore the building before heading back to the visitor center.

Machinery is painted a minty green, and there are hand-written signs labeling parts of the reactor. The control room is open to visitors during the B Reactor tour.

The reactor was completed and went critical — or started up — in September 1944. B Reactor produced the plutonium that powered the first man-made atomic explosion, the Trinity test, in the New ...

The B Reactor at the Hanford site was the world’s first full-scale nuclear reactor. Here, scientists and engineers pioneered the technology behind nuclear reactors.