Some of the SMR designs addressed in this report provide for a long-life reactor core operation in a “no on-site refuelling mode”. The targeted refuelling interval for such SMRs is between 5 and 30 calendar years. Although the fuel burn-up in all these designs is quite moderate and does not exceed the typical values for a conventionally refuelled design of the same technology line, the continuous long-time core operation may result in ageing and fatigue of some safety related structures and components. In view of this it would be necessary to justify that the original safety case is retained throughout the whole long period of continuous plant operation. The regulatory norms providing for such a justification may be not readily available in national regulations. Countries having relevant experience with marine propulsion reactors will have an advantage. Otherwise, a “license-by-test” approach highlighted in Section 9.4 could be helpful.