Korea has developed a liquid breeder blanket and participated in the test blanket module program for ITER. To develop liquid breeder technologies with not only liquid lithium but also lead-lithium (PbLi), an experimental loop for the liquid breeder was constructed at the Korea Atomic Energy Research Institute. The main purposes of the loop are developing components such as an electromagnetic pump, testing the effects of magnetohydrodynamics, and investigating the compatibility between the liquid breeder and other materials. Before operating the loop, the melting and solidifying temperatures of the PbLi and its contamination were experimentally investigated considering cyclic use with the prepared reaction chamber. Melting and solidifying temperatures were [approximately]235°C, and there was no change even with the cyclic test. Because of contamination such as oxidation, however, the composition of PbLi can be changed, which should be considered when operating the loop. The reactions of PbLi and Li with air and water were observed. The PbLi did not react with air or water, but Li showed a severe reaction with them. However, reaction mitigation using nano-particles was found in the experiment.