“Buchanan — Mark Fitzgerald gently guided a gleaming nuclear fuel container into a 40-foot-deep pool, one of the first steps to turn its uranium pellets into 1,000 megawatts of electricity.

“That’s the last time that thing will see the air,” said Daniel Darby, a worker wiping the nearby floors with a special mop that helps safety inspectors track radioactive contamination.

Refueling has become an annual rite of spring here, shutting down one of the two nuclear plants at Indian Point. Officials at Entergy Nuclear Northeast, which owns Indian Point, say it’s not unusual to invest more than $25 million during the operation — not counting the cost of new uranium.

Indian Point 2 is expected to go back online this weekend after it was shut down April 19 for the refueling. During the downtime, a Journal News reporter and photographer spent a day observing the refueling at the heart of the nuclear reactor, under a 200-foot-high concrete containment silo that has become the industry’s most recognizable image.

This is the place where nuclear fission splits uranium atoms, creating temperatures of nearly 550 degrees Fahrenheit to produce steam powerful enough to turn giant turbines. The resulting 1,000 megawatts will power the equivalent of a million homes.

What a visitor notices first about the refueling operation is the size of everything — the bolts that secure the 433-ton, 44-foot-deep reactor vessel are man-size, with heads that no homeowner with an ordinary pipe wrench would dream of tackling.

The reactor has to be big because by the time it’s full, it will hold 193 fuel assemblies — with nearly 10 million uranium pellets that cost about $200 million.

The door to the equipment hatch that allows bigger items in and out of the containment building looks like it came off an aircraft carrier and must be moved into place by an ever-present crane running on a circular track a few feet inside the round building’s 4-foot-thick walls.

Even the work force is big during refueling, swelling to about 2,400, nearly twice the 1,300 workers normally on site.

The most compelling sight in the containment building is the nuclear reactor itself.

Not readily visible under the 40 feet of water used to shield workers from radiation, the reactor retains an element of danger that keeps the uninitiated looking over their shoulders, regardless of where they are.

The reactor core sits in the cavity, looking much like a 15-foot-diameter drain in some huge industrial sink.

This year, as in years past, the reactor doesn’t get its 92 new fuel assemblies until the 193 units in the core are removed for inspections and maintenance.

One by one, the zirconium-encased fuel assemblies are brought out on a flat, underwater railroad car through a 27-foot-long canal connecting the reactor cavity to the spent fuel pool.

A computer-controlled platform the size of a small stage spans the cavity, moving back and forth from the core to the canal.

There, workers lay the assemblies down with pulleys, sending them through the canal where they are picked up by identical machinery.

Lifted into a vertical position, but still underwater, the used assemblies give off a shimmering blue light, like high-powered light sticks in a backyard swimming pool.

There are about 2,000 10-inch-by-10-inch slots in the fuel storage pool, each with a specific, computerized location that holds the 12-foot-long bundles of nuclear rods and their encased uranium pellets.

The used fuel comes out in three categories: 2-, 4- and 6-year-old assemblies. The oldest group will remain behind in the 400,000-gallon cooling tank for holding spent fuel.

It’s the same tank that has been at the center of a leak investigation since August, when the presence of radiated water outside the pool led the company to spend millions to figure out where it was traveling under the site.

High levels of tritium and strontium 90 have turned up during the investigation, and the company is planning more monitoring and says it will take any necessary corrective actions.

Because of the potential for atomic reactions continuing in the pool, putting the oldest in the nuclear equivalent of the attic won’t work — the newer must be interspersed with the older. The weaker assemblies act as a brake on further fission during storage.

New fuel assemblies lie along a wall not far from the storage pool, like shiny miniature skyscrapers. Not yet emitting any radioactivity, they arrived on a flatbed truck weeks earlier from a Westinghouse plant in South Carolina.

Weighing about a half-ton each, they’re eased over to the pool with a crane into workers’ waiting hands and placed in slots.

The new fuel will be mixed in with the strongest of the old fuel, and then put back in the reactor.

Emptying the reactor completely before refueling allows a great deal of work to be done in and around it during the shutdown.

While the reactor is cooled down, crews also go to work replacing huge transformers, cleaning and repairing turbine fins and upgrading vital electronic wiring and machinery. And they replace old uranium-237 pellets with new ones containing the power to produce half the electricity Entergy sells via the region’s power grid.

But even a nonworking, empty reactor gives off radiation that must be carefully managed.

Indian Point workers were reminded of that midway through this year’s shutdown when a crane operator working above the reactor was exposed to radiation levels nearly 60 percent higher than what was planned for his task. The exposure set off a company investigation.

The levels were low enough that the man suffered no health effects, but unplanned exposures like that raise supervisors’ heart rates and regulators’ concerns.

That’s why everything is planned during an outage, even down to the amount of radiation that is acceptable for each person’s daily duties.

Workers move quickly throughout the refueling operation, part of a scripted set of instructions that one veteran nuclear expert likened to a football coach planning as many plays in advance as possible but adapting as needed as the game goes on.

“Almost every minute in an outage is choreographed,” said David Lochbaum, the nuclear safety project director for the Union of Concerned Scientists and a veteran of many refuelings. “There are so many temporary workers, there are opportunities for mistakes, but those are the exceptions. These companies only make money when the reactor’s running, and they want to keep outages as short as possible.”

Lochbaum said that the workers, though temporary, usually are very experienced. They are basically nuclear-industry gypsies who live out of suitcases and work the overtime that is a way of life for refuelings. They can make a six-figure annual income working nine months of the year because the load is so intense.

“Everybody works 12 hours a day, six days a week during the outage,” said Jim Steets, an Entergy spokesman. “There’s a tremendous amount of work that gets done in a short time.”

Creating nuclear energy

• Nuclear reactors basically are machines that contain and control chain reactions, while releasing heat at a controlled rate.

• Nuclear power accounts for about 20 percent of the total electricity generated in the United States, about as much as that used in California,Texas and New York, the three most populous states.

• It comes from the nucleus (core) of an atom, tiny particles that make up every object in the universe and require enormous energy to be held together.

• When the atoms are split into smaller atoms (nuclear fission), they release energy that can then be used for other purposes, such as heating water to create steam that turns electricity-generating turbines.

• The fuel most widely used by nuclear plants for fission comes from uranium, a nonrenewable metal found in rocks all over the world. Once uranium is mined, it is processed into U-235, because its atoms are easily split apart.

• During nuclear fission, a small particle called a neutron hits the uranium atom, causing it to split and release a great amount of energy as heat and radiation. More neutrons also are released, creating a chain reaction.

• The uranium fuel is formed into ceramic pellets, each about the size of a fingertip. Each one produces the same amount of energy as 150 gallons of oil. These energy-rich pellets are stacked end-to-end in 12-foot metal fuel rods. A bundle of fuel rods is called a fuel assembly.

• Fission generates heat in a reactor just as burning coal does in a boiler, turning water into steam. The steam pressure turns huge turbine blades, which in turn drive generators that make electricity. Afterward, the steam is changed back into water and cooled in a separate structure at the power plant called a cooling tower. The water is then recycled.

• Like all industrial processes, nuclear power generation has by-product wastes: radioactive waste and heat.

• Radioactive wastes are the principal environmental concern for nuclear power. The irradiated fuel assemblies are highly radioactive and must be stored in specially designed tanks resembling large swimming pools (water cools the fuel and acts as a radiation shield) or in specially designed dry storage containers. Most nuclear fuel is stored underwater.

• The United States Department of Energy’s long-range plan is for this spent fuel to be stored deep in the earth in a geologic repository, at Yucca Mountain, Nev.

Source: The U.S. Energy Information Administration, a division of the Department of Energy.“

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