b'1969 Zero Power Physics ReactorThe ZPPR was a low-power physics reactor that started up in 1969 and provided physics data for any type of fast neutron spectrum reactor from the smallest space reactor to the largest fast breeder designs. It consisted of two separate honeycomb lattice assemblies that allowed internal core access for precise physics instrumentation. The two lattice halves were moved together before the reactor was brought to power by conventional control rods. Air circulated through the core to maintain a stable temperature. The type of physics data collected required minimal extrapolation to the full-power designs. The reactor was placed into standby in 1990 and disposed of in 2009. Today, the ZPPR facility at the INL Material and Fuels Complex is being converted into the National Reactor Innovation Centers Laboratory for Operations and Testing in the US (LOTUS) and is slated to be home to the Molten Chloride Reactor Experiment (MCRE), the worlds first test of a fast-spectrum, salt-fueled reactor design.47'