How do nuclear plants stay youthful? Maintenance

While most of the nation’s nuclear fleet was built before 1990, it’s a mistake to label these safe, reliable plants as “aging." Nuclear facilities are constantly evolving, as more modern and efficient plant equipment is continuously put into service.

Beginning commercial operation in 1971, Robinson Nuclear is a good example of how nuclear plants evolve. In the past five years, the site has put into place a new stator (a key part of an electric generator, along with an exciter and rotor), low pressure turbine, and built a second Control Room simulator. The simulator is an exact replica of the Control Room and is used to train operators.

“We are continuously monitoring and evaluating our plant equipment to determine what needs to be upgraded or replaced. The plant may have been built in the 1960s, but it’s a very modern operation because nearly everything has been replaced,” Duke Energy’s Robinson Nuclear Site Vice President Ernie Kapopoulos said.

One of the drivers for this change is that a hallmark of the nuclear industry is a strong reliance on preventive maintenance. Preventive maintenance is a strategy of continually monitoring and repairing or replacing equipment before it breaks or becomes outdated. The purpose of this approach is to avoid equipment breaking down or becoming inoperable unexpectedly.

This process is reflected throughout the Duke Energy nuclear fleet.

In addition to Robinson, McGuire Nuclear Station replaced two generator stators in 2012 and 2013. These enormous pieces of equipment, weighing approximately 600 tons, are among the largest and heaviest components in a nuclear plant.

One of the major plant upgrades at Oconee Nuclear is the completion of its Protected Service (PSW) project. The Nuclear Regulatory Commission (NRC) selected Oconee to have an industry pilot for the upgrade and the project took more than two years to plan and implement. The PSW enhances the station’s fire protection program and required more than 100 plant modifications.

Catawba Nuclear upgraded its fire protection from analog to digital. The site replaced 34 fire alarm control panels and more than 1,400 fire detectors in units 1 and 2 from 2012 to 2015. This modernized the fire detection system improved the monitoring abilities for plant operators.

At Brunswick Nuclear, the site upgraded two emergency diesel generators with automatic voltage regulators and governors on three of our four emergency diesel generators. The upgrade modernizes the electronic starting mechanisms on the generators, making them more reliable during emergency operations. These emergency diesel generators are just one of the multiple backup systems in place at a nuclear plant to prevent the site from losing power.

The nuclear industry’s reliance on a robust preventive maintenance program has allowed the nation’s fleet to maintain its youth while also supporting its promise of clean, reliable energy.