Northwest’s only commercial nuclear plant reconnects to the power grid after refueling

Just in time to power air conditioners during a heat wave predicted for portions of Washington, Oregon, and Idaho, the only commercial nuclear power plant in the Northwest reconnected to the electric grid Sunday morning following a brief shutdown.

Following a 65-day shutdown of the nuclear reactor, the Columbia Generating Station returned on June 16 from its biennial refueling outage.

In addition to performing critical and minor maintenance tasks that could not be completed while the reactor was in operation, the planned outage was intended to replace a third of the 764 nuclear fuel assemblies in the reactor core with fresh fuel.

In order to minimize the impact of a temporary halt to nuclear power production, the work, which necessitated the hiring of an additional 2,000 people, was scheduled to coincide with the spring snow melt and runoff in the Northwest, when hydroelectric generation is high.

The third-largest electrical generator in Washington state, the Columbia Generating Station is located in Eastern Washington, around 10 miles north of Richland. It can generate enough electricity to power one million homes.

However, turbine vibration readings rose to higher than anticipated after the nuclear facility was reconnected to the grid and achieved 80% power after the refueling interruption, preventing the unit from operating at full capacity.

On June 23, the facility was disconnected from the grid in order to perform a turbine rebalancing procedure.

Workers from Energy Northwest have been installing two 24-ounce balance weights on the primary turbine for the past week. The weights are made to reduce vibration and enable the turbine to operate at its best.

Over the course of the station’s upcoming two-year operational cycle, Energy Northwest will keep an eye on vibration levels to assess whether any additional balancing is required to sustain safe and dependable operation.

Three low-pressure turbines and one high-pressure turbine make up Columbia’s turbine system, which has a total spinning mass of roughly 1.2 million pounds.

Since the turbines power the primary generator that generates electricity for the area, precise alignment and balancing are critical to dependable performance, according to Energy Northwest.

As the National Weather Service predicts a heat wave that will hit Central and Eastern Washington on Monday and Tuesday and spread into Idaho and Oregon, the plant is back on the grid and producing electricity. There had been a heat advisory.

Installing a new adjustable speed drive system was a significant job completed during this spring’s refueling outage. After a few problems that required turning off the power to fix parts, the system had to be replaced.

According to Energy Northwest, the speed drive regulates the pumps that regulate the water inside the core, which regulates the reactor’s power output.

The water inside the core boils because to the heat generated by a chain reaction, producing steam that powers turbines connected to an electric generator.

Additional tasks included replacing a reactor recirculation pump and motor, inspecting the electrical generator, and fixing the circulating water basin.

The Bonneville Power Administration purchases the nuclear power plant’s generated electricity at cost in order to distribute it.

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The News Tribune, Tacoma, Washington, 2025. Go to the New Tribune website. Tribune Content Agency, LLC is the distributor.

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