Design, calculation and verification by Finite Elements Analysis of a molten salt storage tank (thermal storage, thermosolar plant). Tank of 4m diameter and 14m high, design temperature is 570ºC. The tank is fabricated in stainless steel, SA240 Tp.347H. The scope of the job was the material selection, tank calculation according to API 650 code, verification of allowable stresses according to the ASME VIII Div.1 and the design of all welded joints of the tank. Subsequently, a verification by FEA was carried out due to the high design temperatures.