Hydrogen isotope is a main fuel for nuclear fusion reactors like ITER (international thermonuclear experimental reactor). Metal hydride is considered for the storage of the hydrogen isotope. Hydrogen isotope absorption and desorption are carried out in a metal hydride bed. These reactions require heat removal and supply respectively. Therefore, rapid storage and delivery of tritium are enabled by rapid cooling and heating of the storage vessel. Rapid heating can be achieved with an electrical heater. However, rapid cooling is not easily achieved. A vertical type hydrogen isotope storage vessel containing 1250 g of ZrCo powder is designed to enhance the cooling performance. Two types of cooling method, an external helium circulation and an internal helium circulation loop, are proposed in this study. The transient cool down time from 350℃ to lower temperatures has been estimated. Details of heat transfer analysis and parametric study at each boundary condition are presented in this paper.