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.