| June 7, 1960 | Construction permit CPRR-55 authorizing the Regents of the University of Wisconsin to construct a 10kW (thermal) pool type nuclear reactor issued by the United State Atomic Energy Commission. |
| November 23, 1960 | License R-74 authorizing the Regents of the University of Wisconsin to possess and operate a 10kW (thermal) pool type nuclear reactor issued by the United State Atomic Energy Commission. |
| January 16, 1961 | Initial criticality achieved at 9:10 PM with GE MTR flat plate fuel. |
| March 26, 1961 | Initial criticality achieved on the first operational core. |
| December 7, 1964 | Reactor power increased to 250kW (thermal). |
| November 14, 1967 | Conversion to General Atomic TRIGA fuel with pulsing capabilities and an increase in reactor power to 1000kW (thermal). |
| June 15, 1979 | Completed conversion to General Atomics FLIP TRIGA HEU fuel. |
| September 16, 2009 | Initial criticality achieved at 2:23 PM with General Atomics 30/20 TRIGA LEU fuel. |
| March 25, 2011 | Renewed facility license R-74 issued by the United States Nuclear Regulatory Commission. |