25 1960 Advanced Reactivity Measurement Facilities The ARMF-I reactor was used to determine the characteristics of reactor fuels and other materials subject to testing in the MTR. In tandem with MTR, it helped improve the performance, reliability and quality of reactor core components. In 1962, ARMF-II represented an advance due to its “readout” system, which automatically recorded measurements on IBM data cards, allowing operators to process data quickly in computers.