There are safety-related limits to this flexibility: one cannot at will reduce/augment the "power" (thermal) delivered by a reactor. After each small set of tw

There are safety-related limits to this flexibility: one cannot at will reduce/augment the "power" (thermal) delivered by a reactor. After each small set of tweaks a somewhat durable stable state (or a complete shutdown) must be respected. In the proposed SFEN document it corresponds to the mentions "palier d’au moins deux heures" (at least 2 hours between tweaks) and "deux fois par jour" (max two tweaking sequences per day). The real (observed and useful) ability to follow load at a useful extent is offered by the float (tens of reactors simultaneously active => more flexibility towards tweaking limitations). At this game nothing beats a gas turbine (hydraulic dams are serious contenders).