Process for improving the safety of power assembly, and a power assembly suitable for setting this process.

The method involves injecting a fluid i.e. water, into heat engines (1, 2) so as to increase power (BTP) developed by the engines, without increasing temperature of a movable member of the heat engine or to decrease the temperature, without modifying the power developed by the heat engine. The fluid is taken from a reservoir (30). The movable member is set into motion at a speed limited by a specific maximum speed at an instant, where the fluid is injected when the movable member is moving at a speed faster than the specific maximum speed. An independent claim is also included for a power plant including a main closure unit placed between a heat engine and a reservoir.