Potential methods to widen the pressure-temperature operating window

As a result of changing regulations and increasing radiation embrittlement caused by steadily increasing neutron fluence to the reactor vessel from plant operation, the pressure-temperature operating window within which a plant must be operated is being reduced. This narrowing of the operating window will limit the startup and shutdown operation of the plant, and, if proper actions are not taken, the entire operating window margin may be lost. This paper discusses potential solutions to address the operating window concerns for pressurized water reactor plants. Potential methods described may produce an additional operating window margin of at least 25 to 50 psi and possibly much more margin if two or more methods are used