International Thermonuclear Experimental Reactor (ITER) will be constructed in 2019 according to the JIA (Joint Implementation Agreement) of 7 countries. The ITER fusion fuel cycle consists of fusion vacuum vessel, tritium plant and fuelling system. The tritium plant provides the functions of storage, delivery, separation, removal and recovery of the deuterium and tritium used as fusion fuels for the ITER. The tritium plant systems supply deuterium and tritium from external sources and treat all tritiated fluids from ITER operation through Storage and Delivery System (SDS), Tokamak Exhaust Processing (TEP), Isotope Separation System (ISS), Water Detritiation System & Atmosphere Detritiation System (WDS & ADS) and Analysis System (ANS). In this paper, the functions and design requirements of the major systems in the tritium plant and the status of R&D are described. Korean party is developing the SDS for ITER tritium plant and partially attaining the WDS technology through the construction and operation experience of the Wolsong Tritium Removal Facility (WTRF). Now it is expected that researchers in other fields such as chemical engineering take part in the development of upcoming technologies for ISS and TEP.