Right reliability for the right cost29 May 2019
A new work order visualisation tool is helping US utilities save on maintenance of non-critical components.
HISTORICALLY, THE NUCLEAR INDUSTRY HAS had such a high emphasis on reliability it could result in cases where more money than necessary was spent on component maintenance for a desired level of reliability.
Given today’s challenging market for nuclear power, the industry now focuses on developing maintenance strategies to achieve the right reliability for the right cost. For example, less-frequent inspections of non-critical heating, ventilation and air conditioning (HVAC) components may result in more failures or corrective maintenance, but with no consequence to safe, reliable plant operations.
The US nuclear industry recently developed a strategic plan — Delivering the Nuclear Promise — to drive greater operational efficiency and affordability for customers, while maintaining nuclear safety and environmental protection standards.
Since 2013 seven reactors have shut down in the USA (Crystal River 3, San Onofre 2&3, Kewaunee, Vermont Yankee, Fort Calhoun, and Oyster Creek), and closures of 12 further units have been announced due to increased economic pressures.
To help nuclear operators identify savings opportunities for plant systems and components, the Electric Power Research Institute has worked with its member utilities to develop the Work Order Data Visualisation Tool. “Today, the industry is focusing more on a balance between cost and reliability, specifically for non-critical components. This tool assists our members in taking their first step to identify components of interest and then make informed decisions,” says Jeff Greene, a senior technical leader in EPRI’s Nuclear Maintenance Application Center. This web application enables utilities to view and track historical maintenance costs (including ancillary costs such as construction of scaffolding) and draw insights about where money is being spent.
Released in March 2017, the tool can help utilities to identify the components with the highest costs and examine strategies that balance cost and reliability.
In the past, it was difficult for utilities to fully assess costs across their maintenance regimes. When staff at Exelon’s Quad Cities plant used the EPRI tool, they reviewed more than 30 complex systems with 2700 preventive maintenance tasks scheduled in a 12-month period. The tool made the analysis more manageable by generating charts, tables, and graphs that enabled Exelon to find key trends and identify outliers. As a result, Quad Cities reduced the frequency of some tasks for non-safety- related HVAC equipment, realising $30,000 in annual savings. Plant staff also determined that some motor inspections were more frequent than necessary. Using a less frequent, more consistent schedule resulted in annual savings of $75,000. For some systems, they even addressed unexpected component failures by increasing inspection frequencies.
Exelon used the tool with another application to examine its maintenance strategy for several non-critical components, using 11 years of historical data spanning its nuclear fleet. The company identified its ten costliest non-critical components and streamlined maintenance. This is expected to result in $80 million annual savings across its fleet by the end of 2025.
Researchers have collected data from 21 utilities and used the data to develop a separate app for each utility. Other plans include: demonstrating the tool’s value in analysing other data sets such as those from electronic work packages; expanding it to new companies; and developing new apps to help utilities forecast spending over the next 20 years.