A couple of years ago, my wife and I were looking to purchase a new car. But just as we made that decision, major pricing inflation and supply constraints became an issue. So, we decided to wait. We also knew that we would need new tires before we could sell our current vehicle. Instead of buying the best quality (and expensive) tires, we got the much cheaper ones, knowing we would only use them for a brief period. Why invest in an asset that won’t be serving its purpose for you that much longer, right?

Maintenance can mean no more than keeping the status quo. But plant maintenance programs at U.S. nuclear power plants do that and then some. Even the programs are themselves maintained and improved—and so a long-lived nuclear fleet has improved with time. Read on.

Westinghouse Parts Business (WPB) is excited to be collaborating with Samshin Ltd to provide replacements for obsolete valves using Samshin designs. Samshin has manufactured hundreds of Westinghouse-designed valves and valve parts for applications across the globe with reliable operation for over a decade.

Any method that can enhance safety, reduce risk, and lower costs is worth a second look. When that method proves it has the potential to optimize aging management at any nuclear power plant, it’s time to spread the word.

In 2019, a small team focused on selective leaching began looking for a way to use risk insights to optimize the implementation of deterministic aging management programs (AMPs). What they started soon grew into a large team effort by Constellation, Ameren, the Electric Power Research Institute (EPRI), and the Nuclear Energy Institute (NEI), along with contractors Enercon and Jensen Hughes, to develop a generic framework and then test it in two very different pilot applications.

While the construction of two additional reactors at Slovakia’s Mochovce nuclear plant (Units 3 and 4) may get most of the attention, it isn’t the only major project underway there. In October of last year, plant owner Slovenské Elektrárne commenced the first phase of an effort to revitalize two of the four 125-meter-tall, Iterson-type cooling towers that serve the facility’s two operating reactors—both of which began generating electricity in the late 1990s. Towers #11 and #21 had been refurbished in 2011 and 2012, respectively. The other two, however, towers #12 and #22, had never undergone refurbishment.

Over the past decade, unmanned aerial systems (UASs), more commonly referred to as drones, have played an increasing role in the day-to-day activities of the energy sector. Applications range from visually inspecting wind turbines, flare stacks, pipelines, and facilities to evaluating vegetation encroachment near power lines. Although the benefits of UASs have been reported in these industries, their use in the nuclear community has only recently been explored. For instance, a drone was sent into a waterbox at a Duke Energy facility to inspect for leaks.¹ And at Fukushima Daiichi, a drone was used to conduct a post-accident radiation survey inside Unit 3, and drones are being investigated for use inside the damaged containments.²

The nuclear industry has historically relied on intermittent ultrasonic test and visual inspections of pressurized water reactor components to identify and manage degradation. While this reactive approach has proven to be effective, imagine a scenario in which the degradation could propagate throughout the reactor internals, making a more proactive measure necessary to avoid a major enterprise risk to the plant. Could a utility identify the onset of degradation within the reactor internals during plant operation? If so, could a repair be developed prior to the next refueling outage to prevent additional, cascading degradation? That is exactly the situation that Public Service Enterprise Group (PSEG) and Westinghouse engineers were able to navigate over the course of the 2019–2020 operating cycle at Salem Unit 1, resulting in a tremendous success for the plant and a historic landmark in the nuclear industry, while earning the team a 2021 Nuclear Energy Institute Top Innovative Practice (TIP) award.

The Zephyr system uses probes for steam generator inspections. Photos: APS

The Palo Verde Nuclear Generating Station, a three-unit pressurized water reactor plant operated by Arizona Public Service Company, has started using an inspection technology relatively new to the nuclear industry. The technology, called smart pigs (an acronym for “piping inline gauges”), has previously been employed by oil and gas companies for inspecting and cleaning underground pipes. After testing and analyzing smart pig products from several companies, Palo Verde’s underground piping consultant, Dan Wittas, selected a smart pig suitable for navigating the tight-radius bends in the plant’s spray pond piping. The spray pond system consists of piping, a pump, and a reservoir where hot water (from the Palo Verde plant) is cooled before reuse by pumping it through spray nozzles into the cooler air. Smart pigs work by using the water’s flow through the piping to move an inspection tool within the pipe itself. The technology replaces the previous method of pipe inspection, in which various relatively small sections of piping were unearthed and directly inspected, and were considered to be representative examples of the overall piping condition. In contrast, the smart pigs obtain corrosion levels for the length of piping traveled through and allow a corrosion baseline to be established.

Ratliff

Harris

When Floyd Harris began working at Duke Energy’s Brunswick nuclear plant about 24 years ago as a radiation protection technician, robotics and remote monitoring were considered tools for radiation protection and nothing more. Now, teams from across the site, including engineering, maintenance, and operations, rely on the system of robots and cameras Harris is responsible for. “If you want to put those technologies under one umbrella,” says Harris, who now holds the title of nuclear station scientist, “it would be monitoring plant conditions.”

That monitoring is critical to effective plant maintenance. As Plant Manager Jay Ratliff explains, the goal is to “find a problem before it finds us” and ensure safety and reliability. Nuclear News Staff Writer Susan Gallier talked with Ratliff and Harris about how robotics and remote systems are deployed to meet those goals.

At Brunswick, which hosts GE-designed boiling water reactors in Southport, N.C., ingenuity and hard work have produced a novel remote dosimetry turnstile to control access to high-radiation areas, an extensive network to handle data from monitoring cameras, rapid fleetwide access to camera feeds to support collaboration, and new applications for robots and drones.