Thus if one considers only new or modern nuclear units, it seems reasonable not to consider additional investment costs for load following capabilities, since they can be considered sunk costs, regardless of the choice of operating mode. Similar reasoning can be applied to fuel elements: the additional requirements for fuel design are already priced into the fuel cost, regardless of the operational mode of the reactor. According to AREVA, EDF and the French regulatory authority, there is today no clear evidence that load following will accelerate the ageing of NPPs, and only a very small number of pieces of equipment could be adversely affected (Pouret and Nuttall, 2007). If load variations are performed within design specifications (in terms of extent and frequency of load modulations) the operational lifetime of the power plant should not be affected.