While the Nuclear Regulatory Commission (NRC) has highly specific guidelines for monitoring the effectiveness of nuclear power plant maintenance, the efficiency of the maintenance plan can vary widely, thereby increasing risks of overall cost versus profitability measures. Consequently, increased efficiency in nuclear plant maintenance plans is vital to optimum operation.
There is essentially one primary goal to optimizing a maintenance schedule for a nuclear power plant that actually goes hand in hand with safety. This is the goal of balancing the need for minimal maintenance occasions and offline procedures while effectively eliminating failure rate—all while maximizing the safe lifecycle of components.
In other words, the goal is to minimize the cost of operation while maximizing the plant’s reliability and profitability. This is true for every plant regardless of its age, type, capacity, operational parameters or other specifics inherent to each plant.
In almost every instance, nuclear power plants are best served by a Reliability-Centered Maintenance (RCM) program that balances interval-based, condition-based, and proactive maintenance practices. Ideally this is developed while the plant is still on the drawing board. Even with development of such a plan at the nascent stage, unforeseen parameters during the plant’s lifecycle can facilitate the need for plan modifications.
Oftentimes, these unforeseen parameters involve economic factors outside of the purview of the owners/license holders that impact personnel training and equipment necessary for state-of-the-art maintenance procedures. This confluence of factors is often best served by the introduction of third-party maintenance specialists.
In nuclear plant maintenance plans, corrective maintenance (Component failure replacement) is an unacceptable approach to virtually every system of a nuclear power plant. While preventive maintenance (pre-end-stage predictive life replacement) is far better, it often lacks the accuracy that is necessary to maximize component or system lifecycles that are designed to exceed stated manufacturer lifecycles. This can be due to onsite construction variables, component manufacturer-applied lifecycle cushion as well as the variability of usage in the field of that component for any given scenario.
In order to ensure that an RCM program is both efficient as well as being optimally safe and cost effective for plant operation, it must be based on detailed inspection parameters that are part of daily operation processes. In some cases, the intervals of operational interface by onsite operators can facilitate inspection opportunities that happen over even shorter durations of time. The detailed log that accompanies and interprets these ongoing inspections is not only a major factor in smooth regulatory inspection processes, but is also a key component of the development of historical data on in-use lifecycle observational data.
Working with a third party nuclear power plant maintenance provider becomes another key component by way of complete inspections where certain plant processes must be taken offline. Ongoing and historical maintenance and inspection data will inform the type, level and duration of specific maintenance procedures as well as provide the opportunity for any preemptive repairs such as for coatings as well as structural and component replacement.
The first such inspection informs the formation of future nuclear power plant maintenance scheduling. Ideally, this type of detail enables maximizing the safe and effective lifecycle of components, structures and assemblies. The results are a balance between efficient operation that maximizes operational time while lowering the potential number of maintenance cycles that leads to lower plant costs and higher profitability.
John Merrick is the owner and president of The Merrick Group, Inc. He has over 25 years of experience with coordinating national and international sales efforts for nuclear and fossil fuel related maintenance projects. He has successfully completed projects in over 30 nuclear and fossil fuel sites.