Alloy 617 is being investigated as a candidate for application in next generation nuclear plants (NGNPs), including the very high temperature reactor (VHTR). Creep deformation concerns the lifetime and failure of heat exchangers used at the very high operating temperatures and pressures of such plants. In order to meet the American Society of Mechanical Engineers’ Boiler and Pressure Vessel code (ASME B&PV), and be certified for use in NGNPs, a thorough understanding of creep must be demonstrated. Current methods of testing creep have limitations and there remains uncertainty and controversy as to the applicability of these tests to more complex designs[1,2]. The aim of this research is to relate data from uniaxial laboratory creep tests to multiaxially loaded service components.