Photo: Rocky Flats Plant | Historical, SW Plutonium Bldg View – DOE

Looking southeast at the plutonium operation Buildings 771, 776/777, and 707, July 1, 1969. Building 771, in the foreground, was built in 1952 to house all plutonium operations. By 1956, it was no longer adequate for production demands. Building 776/777 were constructed to house plutonium fabrication and foundry operations.