The role of IC systems in power uprating projects

1. The role of I&C systems in power uprating projects

2. Why to uprate? Market changes induce the claim to operate the plants in an ever increasing efficiency. Efficiency can be increased either by a better utilization of existing capacities or by increasing the capacities. The utilities are aiming for additional production through the better utilization of available assets. Gaining public acceptance to increasing existing nuclear power plant capacity is significantly easier than that to constructing a new NPP.

3. Conditions enabling power uprating The average age of the nuclear units operating for the time being is above 20 years. The units were designed in the mid-seventies. Today, there is a more accurate knowledge on the behavior of structural materials and integrated effects of external and internal factors exerted on the components. Today demands affecting components during transients can be defined more exactly, uncertainties of calculations can be reduced, and, as a result, the conservatism applied in the original design can be reduced. Today more accurate and reliable control and assessment methods are available (accuracy of measurements, reduction of detection thresholds, etc) Knowledge related to nuclear fuel and core thermal hydraulics also had a considerable development. Fuel utilization arose to one and a half times of that in the eighties.

4. Definition of power uprate The process of increasing the maximum licensed power level at which a commercial nuclear power plant may operate is called a power uprate. (Definition from the U.S. NRC) Types of power uprates measurement uncertainty recapture power uprates stretch power uprates extended power uprates

5. Basic ways of power uprating Reducing uncertainty Improving efficiency Increasing thermal power