Massive transformer makes long voyage to FPL’s Turkey Point nuclear plant
06/06/2012 5:00 AM
07/02/2012 6:13 PM
Tugboat captain Nick Colomero pulled up to the barge landing at Turkey Point Nuclear Power Plant last month with a special shipment: a $10 million, 592,000-pound transformer from Europe.
The behemoth electrical device was designed with an oddly shaped top to fit through the railroad tunnel near Weiz, Austria, where it was built by Siemens Energy. No manufacturer in the United States had the capability to construct the “extra high voltage” transformer when it was put out to bid several years ago.
The journey took 10 weeks and covered 7,200 miles by train, cargo ship and barges averaging 7 miles per hour. The route traversed the Danube River, Atlantic Ocean, Gulf of Mexico and Moser Channel, which runs under the Seven Mile Bridge in the Keys. Thousands of extra miles were required for a stop in Mobile, Ala., because local ports couldn’t lift the 33-foot long, 14-foot wide, 15-foot high unit, made primarily of steel and copper.
Five days were unexpectedly spent holed up in Apalachicola, riding out Tropical Storm Beryl. The last half-mile was aboard a German-machine called the Goldhofer, which looks like a caterpillar with 144 tires and features a hydraulic system to handle the 268 tons — far too heavy for most roads.
And all this for a “spare.”
“Absolutely, it was worth it,” said Cara Smith, project manager for Florida Power & Light.
The transformer is an integral part of the nuclear power plant’s $1 billion, head-to-toe makeover. Nearly 6,000 components are being replaced or upgraded: pipes, valves, generators, rotors, fans and turbines. All are important, even the backups, in the complex puzzle.
When the upgrade — the most ambitious ever attempted at a U.S. nuclear power plant — is done in spring 2013, Turkey Point’s two nuclear units will be able to produce about 15 percent more electricity, enough to power about 270,000 more residential homes in South Florida and elsewhere on the grid. This will be done using basically the same amount of uranium fuel, consisting of solid ceramic pellets that produce electricity through a process called fission. Not a drop of fuel oil or natural gas is used.
“It’s almost like building another power plant,” Smith said. “But here you are taking existing units and running them more cleanly and efficiently. And nuclear fuel costs are dirt cheap compared to natural gas or fuel oil.”
The number of additional residential homes to be powered could increase if the new spare transformer from Austria is ever called to duty to replace one of the two existing transformers. While the new transformer (1,028 mega volt amps) is rated higher than the two existing upgraded ones (now at a maximum 970 mvas), it was not practical to make the switch now due to the logistics nightmare of the overall upgrade, Smith said.
For now, the $10 million spare is a “very cheap insurance policy,” said Turkey Point’s David Sluszka, a liaison between the numerous contractors and the plant.
It would cost the plant about $1.5 million a day in fuel replacement to supply the same amount of power. The transformer took two years to build, and that was after nearly two more years of design and acquiring time-consuming permits.
Transformers are integral to any power plant because they convert the generated 22,000 volts of electricity into high voltage (230,000 volts) for cheaper and more efficient long-distance transmission through wires and poles of the grid. “Think of it like higher water pressure going through pipes,” Sluszka said.
Other transformers convert the high voltage back to lower voltage for household use.
The old original spare, built in the 1970s and never used but still in working condition, cannot be upgraded. FPL tried to sell it, but those interested found it would cost more for transport than it was worth. Miami Transformer bought it for its parts and valuable steel and copper.
Normally, about 800 people work at the two nuclear units at Turkey Point, which also has a natural gas combined cycle plant and two fossil fuel units to produce electricity.
But during the construction part of the upgrade, which began more than two years ago, the staff has soared beyond 5,000. They work 12-hour shifts, six days a week. Many are foreigners because there were not enough skilled laborers available in the United States, Sluszka said.
Turkey Point opened in 1961 and added nuclear power in 1974. The first major overhaul on the two nuclear units was done in the 1990s, post Three Mile Island, Sluszka said.
It was in 1979 that a partial nuclear meltdown at the Three Mile Island power plant in Pennsylvania resulted in the worst accident in U.S. commercial nuclear power plant history, with the release of small amounts of radioactive gases and iodine into the environment. As a result, the industry put in place more rigorous safety regulations.
Since 9-11, security also has become a critical concern. Every worker at Turkey Point now goes through rigorous background checks and psychological tests. Getting into secure areas requires passing through metal detectors and other security devices.
On a recent afternoon, with temperatures in the 90s and shirt-soaking humidity, Sluszka gave a tour of the work being done on both mirror-image nuclear units — one that is operating and the other that is offline for 144 days for refueling of the nuclear material and for the upgrade. The second unit will go offline around November for refueling and its final upgrade work.
Sweaty workers were in every nook and cranny of the nuclear units, which span several acres and are several stories high. “It kind of looks like spaghetti,” Sluszka said of the temporary multicolored wires that were wrapped around each other and going in all directions to power welding equipment.
Fans, valves and pipes looked familiar, only super-sized. The giant maze of interconnected parts all need to work in unison.
“Engineers designed this,” Sluszka said. “Lots and lots of engineers.”
Part of the upgrade includes adding safety measures. Missile barriers are being constructed to protect piping and other critical structure in the case of hurricanes, tornados and even terrorist missile strikes.
“If the worse case occurs, guys will be able to control the plant,” Sluszka said. “Our number one thing is to always keep the safety and health of the public in mind.”
Nuclear power is created by a nuclear reaction that occurs inside a containment area, where water is piped through but is never exposed to the radiation.
The heated water makes steam, “just like old coal locomotives.” That steam becomes the energy that turns a turbine and generator to produce electricity. The energy is the same whether created by gas, oil or nuclear, Smith said.
While nuclear fission is unlimited, the limitations to create electricity are related to the plant’s ability to handle heat.
While heat is needed to create energy, in parts of the process heat also is the enemy, Smith said.
The steam needs to be cooled to convert back to water, so it can repeat the cycle through the closed system. Part of the project is making the cooling water lines more robust.
“If they can handle more flow, they can handle more steam,” Smith said. “If they can handle more steam, they can create more power.”
Heat also is damaging to transformers, which are cooled by about 19,000 gallons of mineral oil, which does not need to be replaced.
Designers of the new transformer took into account its long trek over land and water, said Wade Lauer, Siemen Energy’s vice president of transformers for the United States.
“The whole transformer works on clearances,” Lauer said. “There is a risk if it shakes.”
The transformer was put in the bottom of the hull of the Star Eagle cargo ship. On the 180- by 150-foot barge, it was held down with 25 half-inch chains. “It won’t move an inch,” Colomero said a few minutes after he ended the 966-mile journey from Mobile.
The barge contained only the transformer’s shell. Ten semi-tractor trailers are hauling all the accessories — coolers, radiators, pumps and other parts — from Mobile, where they also were on the Star Eagle. It will weigh 850,000 pounds when it’s all put together in about a month.
The transformer’s new home for now is on a foundation next to the two nuclear units. Its shelf life is expected at 30 to 40 years.
FPL is doing a similar overall upgrade at its other twin nuclear power station in St. Lucie County. Parent company NextEra Energy also owns nuclear power plants in New Hampshire, Iowa and Wisconsin, making it the third largest operator of commercial nuclear power plants in the United States. The emissions-free electricity powers more than 5 million households.
“It’s clean energy,” Smith said.
But more nuclear power plants are not built because of the fear factor for some, and because they are initially expensive to construct. They also require an extensive licensing process that takes 10 years or more.
“But once they are built, they are very efficient,” Smith said. “And, they last a long, long time.”
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