Catawba Nuclear Station: Through a different lens

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Morning comes to Catawba Nuclear Station, located in York County, S. C. on Lake Wylie. The two units at Catawba generate approximately 2,258 megawatts of electricity—enough electricity to power approximately one million homes—making it the second-largest operating nuclear plant in Duke Energy’s fleet.

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Each of the two units at Catawba has two emergency diesel generators that can provide power to the station in an emergency. One generator can provide more than enough power to safely shut down the unit.

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Catawba Nuclear Station has six cooling towers, three for each unit. What you see rising from the towers is actually water vapor, or steam.

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Stairs leading to the top of the cooling towers. Each ascending circular level of the cooling tower cantilevers slightly over the level below (looking similar to an upside down lamp shade).

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The cooling towers are huge circular concrete structures, seven stories high, and 270 feet in diameter (almost one football field) with thirteen huge (28 feet) fans on the top deck. Each tower circulates about 210,000 gallons of water per minute.

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The switchyard—where power from the nuclear station first stops on the way to  customers.

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The whole process of making electricity is monitored in the control room where is a team of operators licensed by the federal government makes sure our plant operates safely and efficiently. To maintain their licenses, operators must complete requalification training and examination programs — spending one week of every five weeks in required training for the duration of their careers. Additionally, they must pass exams to be certified physically and mentally fit to be an operator.

A Reactor Trip: An Important Nuclear Safeguard

EBR-I. Photo courtesy of WikipediaThe priority for every nuclear power plant is the safe, reliable operation of the plant. The industry’s commitment to this principle is absolute – a cornerstone of the nuclear safety culture is “conservative decision making.” What this mean is if there is ever any threat to the safe, reliable operation of a plant, no matter how remote or unlikely, the decision is always to take the most cautious course of action, which may be to immediately shut down the plant.

The automatic or manual shutdown of the plant is referred to as a “trip” or “scram.” The shutdown occurs when the reactor is shutdown by rapidly inserting control rods into the fuel core to instantaneously stop the fission chain reaction. Trips can occur either automatically or manually when certain predetermined parameters indicate the plant is not operating as expected.  The parameter values, often referred to as trip points, are selected with enough margin to ensure safety and protect plant equipment. The concept is much like a circuit breaker in your home.  The circuit breaker will trip when a predetermined level is reached so the design limits of things like wiring, receptacles and other devices are not exceeded.

Control rods are designed to insert into the core to stop the fission process in less than two seconds.  The time required to return the power plant to service is determined by the time required to assess and correct the cause of the trip limit being exceeded.  A normal time to recover from a minor problem would be roughly 48 – 96 hours.

Plant trips and the startups are practiced regularly in every nuclear plant’s training organization. Exact replicas of plant control rooms are used to simulate different scenarios that could lead to a trip. It’s an approach and environment that’s very similar to an airline flight simulator.  In the event of a plant trip, any improvement opportunities and best practices are captured during post-trip reviews.  These reviews of operator and equipment performance are evaluated for inclusion in future simulator training and also shared with the nuclear industry.Control room scram button. Photo courtesy of Wkipedia Nuclear plants are operated with multiple redundant safety barriers in place to protect public safety. Operators work to avoid trips by constantly monitoring, assessing and correcting any negative trends in plant performance. Trips are an excellent safeguard that ensure the continued safe operation of nuclear plants.   

The Nuclear Workforce

Reactor operators monitor plant conditions in the control room of McGuire Nuclear Station.

Careers in the nuclear industry offer rewarding work with competitive salaries and benefits. The nuclear industry does not just employ scientists and engineers, but also accountants, nurses and public relations personnel. Professionals from every field are needed.

Over the next ten years, close to half of the workforce in the nuclear industry will retire. As the nuclear industry grows, more opportunities will become available. Duke Energy has developed a systematic, comprehensive program to create and reinforce the infrastructure needed to develop the next generation nuclear workforce.

By forging partnerships with organized labor, government and professional groups, enhancing recruitment efforts and fostering supporting public policy, Duke Energy is responding to a changing workforce.

The average nuclear power plant employs nearly 500 people in local communities at salaries typically higher than the average salary in the area. At Duke Energy, we employ approximately 1,000 employees at each of our sites and 1,000 -1,200 during refueling outages.

Click here to learn more about careers in the nuclear industry or check out Duke Energy’s career opportunities.