b'1964Advanced Test Reactor CriticalAs the Advanced Test Reactor was being built, the ATR Critical Facility (ATRC) helped verify for reactor operators the effectiveness of control mechanisms and physicists predictions of power distribution in ATRs innovative new core design. Critical facilities like ATRC are necessary for operation of high-power test reactors. Theyre used to analyze neutron flux distributions, excess reactivities and fuel loading requirements before new experiments can be loaded into ATRs much more powerful core.37'