Rotating Target Neutron Source (RTNS-II) Door, 1979.
A Lawrence Livermore National Laboratory employee is opening the world’s heaviest door on a hinge – a 97,000-pound concrete filled door—which was used to shield the Rotating Target Neutron Source-II (RTNS-II) at the Laboratory.
RTNS-II was the world’s most intense source of continuous fusion (14 MeV) neutrons. Scientists from around the world used it to study the properties of metals and other materials that could be used deep inside fusion power plants envisioned for the next century.
The door was eight feet thick and nearly twelve feet wide at the outside. The door could be opened or closed both manually or by remote control. A special bearing in the hinge allowed a single person to move the door, which weights as much as 32 automobiles (at 3,000 pounds each).