Long-Term Operation and Basic Corrosion Test in an Experimental Loop for Liquid Breeder in Korea

Korea has developed a liquid breeder blanket and participated in the test blanket module (TBM) program within the international thermonuclear experimental reactor group with a helium-cooled molten lithium (Li) concept. Based on this concept, helium and liquid Li were used as a coolant and breeder, respectively. Additionally, ferritic-martensitic steel (FMS) was considered as a structural material. However, according to our strategy for developing a liquid breeder TBM and its more relevant DEMO concept, not only liquid Li breeders, but also lead-Li (PbLi) breeders were considered. An experimental loop for a liquid breeder (ELLI) was constructed for the purpose of validating the design and fabrication of our electromagnetic (EM) pump; testing the effects of the magneto-hydro-dynamics; and investigating the compatibility of PbLi using structural materials such as FMS. In the ELLI, Pb-15.7Li, where Li is 15.7 at % (called PbLi hereafter), is used as the breeding material, and the EM pump circulates it through the loop. The maximum operating pressure and temperature in the loop are 0.5 MPa and 550 ^°C, respectively. In this paper, performance tests with the EM pump were carried out. During the three separate experiments, the EM pump was operated for 250 h with a speed of 0.16 m/s for corrosion tests. For a material of corrosion test, tubular-type specimens and cylindrical-type specimens were fabricated and installed in three test pots of the loop. After installing the specimens into the loop, the corrosion test was performed while the EM pump was operating with a 0.16 m/s flow rate at 340 ^°C for 250 h.