Why don’t all nuclear plants have cooling towers?

Water is pumped from the cooling tower basin to the plant’s condenser, and back to the cooling tower. Some of the warmth is immediately released by spraying over a grid, allowing some of the liquid to evaporate.

Water is pumped from the cooling tower basin to the plant’s condenser, and back to the cooling tower. Some of the warmth is immediately released by spraying over a grid, allowing some of the liquid to evaporate.

On a clear day, you can easily see the Harris Nuclear Plant’s 523-foot high cooling tower from downtown Raleigh, about 20 miles away. It’s become an iconic symbol of the power plant. On the other hand, if you drive 180 miles southeast to the Brunswick Nuclear Plant on the Atlantic coast in Southport, N.C., you won’t see a cooling tower.

Since both are nuclear power plants, why does only one have a cooling tower?

First, let’s review the purpose of a cooling tower. All thermoelectric power plants that use heat to make steam to drive a turbine generator need a system to cool water. The majority, including Harris and Brunswick, use a once-through cooling system, where water is drawn from a lake, river or reservoir. The difference between Harris and Brunswick is really based on their location and the source of cooling water.

Second, it is important to note that the cooling systems at both plants are designed for plant cooling and to protect the environment. In fact, the use of cooling towers for new power plants larger than 100 megawatts (MW) was mandated by the Clean Water Act of 1972 to protect the aquatic life in the river or lake from which the cooling water is taken.

Harris Lake, with a surface area of 4,100 acres, was constructed to provide cooling water for the Harris Plant. Water is pumped from the lake into the cooling tower basin. Water from the cooling tower basin circulates through the plant’s condenser, absorbs heat from the steam and travels back to the cooling tower. The water is then sprayed onto a grid in the center of the cooling tower. Cool air flows up from the center, which is hollow, and passes the warm falling water.

To complete the cycle, a discharge pipe returns water to Harris Lake within a degree or two of the lake’s normal temperatures. This ensures there is no harm to the fish in Harris Lake. The lake is popular for sport fishing, boating and water skiing.

The cooling process is similar at the Brunswick Plant, except for the source and size of the source of water. Instead of drawing water from a manmade lake into a cooling tower basin, the water is pumped into the plant’s condensers directly from the Cape Fear River. The warm water is then discharged and cooled as it travels more than five miles through a manmade discharge canal until it finally meets its destination – the Atlantic Ocean! The warm water quickly dissipates in the ocean, causing no harm to the aquatic environment (and actually makes quite the fishing spot for local anglers).

The Brunswick Nuclear Plant’s two reactors came online in 1975 and 1977, and Harris, which has one reactor, began operating in 1987. Today, it is more likely that cooling towers would be required on all new nuclear plants to meet environmental regulations than in the early 1970s, when the Brunswick Plant was under construction. In fact, only two of Duke Energy’s six operating nuclear sites use cooling towers. All five new reactors currently under construction in the U.S. include the use of cooling towers.

Just the Facts:

  • Cooling towers are constructed for plant cooling and to protect aquatic environments.
  • The nuclear reactor is located inside a containment building, not the cooling tower.
  • The cloud at the top of cooling tower is not radioactive. The water in the reactor stays in a closed system, never coming into contact with the water in the cooling tower.
  • There are more than 250 cooling towers on power plants across America, and fewer than 100 on nuclear plants.
  • Among the Duke Energy nuclear fleet, only two plants — Harris and the Catawba Nuclear Station — use cooling towers.  The other sites (McGuire Nuclear Station, Oconee Nuclear Station and the Robinson Nuclear Plant) all use large manmade lakes as makeup water for plant cooling.

Duke Energy Inspires Young Minds during National Nuclear Science Week

NNSW_final_logoLast week, dozens of nuclear professionals across Duke Energy’s nuclear fleet met with hundreds of students to give them a lesson on nuclear power as part of National Nuclear Science Week. Teammates flocked to local schools while others welcomed homeschoolers to their site’s energy education centers where outreach efforts ranged from interactive presentations and hands-on activities to essay and drawing contests. Several of the events were orchestrated by the site’s North American Young Generation in Nuclear (NA-YGN) and Women in Nuclear (WIN) groups.

Curious to know what went on during National Nuclear Science Week? Below are some key outreach efforts held during the week-long celebration:

  • Crystal River Nuclear Plant: More than a dozen Crystal River employees – equipped with infrared cameras and protective clothing used at the plant – participated in five educational events at local Boys and Girls Clubs and middle schools. In all, the CR3 team gave 16 presentations, teaching more than 400 students the importance of nuclear generation as an environmentally friendly source of power.
  • Brunswick Nuclear Plant: Brunswick’s nuclear teammates hit the ground running last week and met with nearly 25 schools in the area. They helped spark awareness about nuclear science and careers by leading a poster contest depicting “why nuclear power is cool” and invited robotics teams from local high schools to view the robots used at the power plant.
  • McGuire Nuclear Station: Nearly 120 homeschoolers flocked to the EnergyExplorium, the site’s energy education center. The students were first introduced to nuclear power by listening to a brief presentation, then students applied what they learned by participating in a series of five hands-on activities which included a demonstration on half-life vs. radioactive decay using M&Ms and a game of 20 questions.
  • RoddyHarris Nuclear Plant: Teammates partnered with local schools and held a “Roddy Nuclear” drawing contest – the NA-YGN mascot used to promote National Nuclear Science Week. “Roddy” resembles a uranium fuel pellet – the energy source for nuclear power plants. Duke Energy also sponsored the N.C. State American Nuclear Society chapter meeting, providing speakers for a question and answer panel with university students. 
  • Oconee Nuclear Station: In addition to promoting the drawing contest at a local school, the World of Energy, Oconee’s energy education center, held its Fall for Energy homeschool day. Students were able to participate in nuclear dress out exercises and learn how electricity is made.

National Nuclear Science Week is just one of many events the nuclear fleet hosts each year. Through partnerships with WIN and YGN, as well as programs held throughout the fleet’s three energy education centers, Duke Energy has reached thousands of students and teachers each year through an extensive public education and engagement program.

National Nuclear Science Week is an annual celebration organized to draw attention to all aspects of nuclear science and the vital role it plays in the lives of Americans, as well as encourage education and awareness of new nuclear technologies and careers within the industry. Interested in learning more about National Nuclear Science Week, click here.


Harris Energy Education Center Evolves Over the Past 25 Years

Harris Nuclear Plant

Harris Nuclear Plant

The Energy and Environmental Center at the Harris Nuclear Plant has undergone many facelifts since the mid-1980s when it first opened.  That was a few years before the Harris Plant, located about 20 miles south of downtown Raleigh, came on line in 1987.

Early on, the center focused primarily on acquainting the community with the prospect of having a nuclear plant as a neighbor. Center staff conducted educational programs on site but also spent a lot of time visiting the community while the plant was under construction.

At that time, the area around the plant was sparsely populated farmland, with only about 20,000 people residing within a 10-mile radius. Today, the surrounding population numbers about 103,000, with burgeoning residential neighborhoods in the adjacent towns of Apex, Holly Springs and Fuquay-Varina.

Harris Energy and Environmental Center

Harris Energy and Environmental Center

In addition to programs at the Energy and Environmental Center, visits often included a driving tour of the plant’s owner-controlled area. That all changed after 9/11. Lisa Tutor, a 27- year company employee who worked at the center in the mid-1990s, remembers the earlier years. “Security was always tight, but we used to give more plant tours pre-9/11 and had more flexibility,”  she said, “as long as visitors were over the age of 18.”  As a matter of fact, some nuclear plants closed their education centers — either permanently or temporarily — after 9/11 due to new federal requirements for controlling vehicular access.

The center’s latest facelift, completed in 2008, included a complete overhaul of the auditorium, lobby, exhibit area and classroom. One of the first things visitors notice is a waterfall in front of the building that is powered by four 170-watt solar panels. In addition to the basics on energy and electricity, the center’s interactive exhibits focus on emergency preparedness, security, the history of the Harris Plant, transmitting electricity, alternative energy and energy efficiency.  A How it Works exhibit even includes a built-to-scale model of the plant’s iconic 523-foot tall cooling tower.

exhibit 2

In addition to student and adult programs, the Energy and Environmental Center holds a special open house each year that includes learning stations and tours of the plant’s emergency operations facility and control room simulator, an exact replica of the plant’s control room used for training plant operators. The event drew close to 200 people of all ages in 2012. This year’s Community Day is scheduled for Saturday, September 7, from 10 a.m. to 2 p.m.

For more information about the Harris Energy and Environmental Center, visit http://www.duke-energy.com/harris or call 919-362-3261. Individual and group visits are arranged by appointment on weekdays.