First New U.S. Nuclear Reactor in Two Decades to Begin Fueling in Tennessee

A Gen II Westinghouse pressurized water reactor, designed over a quarter century ago, will go online by the end of the year

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First New U.S. Nuclear Reactor in Two Decades to Begin Fueling in Tennessee
In this 29 April 2015 photo, a worker walks past Unit 2 at the Watts Bar Nuclear Plant near Spring City, Tenn., which was still under construction,
Photo: Mark Zaleski/AP Photo

Yesterday, U.S. federal regulators approved an operating license for Unit 2 of Tennessee Valley Authority's Watts Bar nuclear power plant; it's only taken 19 years and almost 4.5 billion dollars. The Gen II plant should be producing power by the end of the year, and it shouldn’t bother you in the least that we mostly stopped building Gen II reactors sometime in the mid ‘90s. 

The Tennessee Valley Authority (TVA) began construction on two pressurized water reactors (PWRs) in 1973. Unit 1 was completed in 1996, while construction on Unit 2 was halted in 1988 when it was 80 percent complete due to a reduction in the predicted growth of power demand. TVA resumed work on Unit 2 in 2007, and it’s now gotten approval to load nuclear fuel into Unit 2 and to begin testing. The goal is to generate 1,180 megawatts of power by the end of this year.

Unit 2 (and the currently operational Unit 1) are both Gen II four-loop pressurized water reactors, built by Westinghouse. Generally, Gen II reactors are distinct from more modern Gen III reactors in that Gen III offers improved safety, increased efficiency, and simpler, more reliable designs. For example, four reactors based on the more modern Gen III design, known as AP1000, are currently being built in the U.S. Compared to a Westinghouse Gen II PWR, the AP1000 contains 50 percent fewer safety-related valves, 35 percent fewer pumps, 80 percent less safety-related piping, 85 percent less control cabling, and 45 percent less seismic building volume.

That's a lot less to break down. And when the newer generation’s passive advanced safety features are taken into consideration, the AP1000 reactors should be about 100 times as safe as existing plants. If an accident happens, the AP1000 will shut itself down without needing any human intervention (or even electrical power) within the first 72 hours. What’s more, only a small amount of water transfer (about ten garden hoses worth) is necessary after that to keep the reactor stable.

imgImage: Argonne National Laboratory

We certainly don't mean to suggest that Watts Bar 2, a Gen II pressurized water reactor, is unsafe or anything. Pressurized water reactors have passive safety systems of their own, including control rods held in place by electromagnets so that if power is lost, gravity will cause the reactor to shut itself down—although the pumps that transfer coolant in and out of the core require electrical power to work, so in the event of a blackout, the plant is reliant on generators to keep it cool. Our point here is simply that this “new” reactor is based on a quarter-century-old design, and that nuclear power has gotten orders of magnitude safer since then.

There are strong arguments that, overall, nuclear power is far safer than coal, although as recent accidents have shown, there's still significant room for improvement in reactor designs. And improvements are certainly being made: Gen IV reactors are hundreds of times more efficient in their use of fuel, produce waste that is safe after tens of years (instead of thousands), and are even safer. However, we're hoping that by the time Gen IV reactors are ready for construction (sometime in the 2030s), fusion power will have completely taken over electric power generation.

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An aerial photo shows a large solar-photovoltaic generating plant.

The Sun Metals solar farm, completed in 2018, supplies electricity to a zinc refinery in Townsville, Qld., Australia. The AUS $200 million, 120-hectare plant can supply 124 megawatts under ideal conditions. The plant is now owned by Ark Energy, a subsidiary of Korea Zinc, which also owns the adjacent refinery. By the end of 2023, Ark Energy plans to commission a fleet of fuel-cell trucks powered by green hydrogen to haul zinc concentrates and ingots between the refinery and a nearby port.

Ark Energy

For several months now, 20 teams of Australian high-school students have been designing fuel-cell cars to compete in the country’s inaugural Hydrogen Grand Prix. They’ve been studying up on renewable energy, hydrogen power, and electric vehicles, preparing for the big day in April when their remote-controlled vehicles will rumble for 4 hours in Gladstone, a port city in Queensland. The task: make the most of a 30-watt fuel cell and 14 grams of hydrogen gas.

A few months later and some 800 kilometers up Queensland’s coast, Grand Prix corporate cosponsor Ark Energy aims to apply the same basic hydrogen and fuel-cell components—albeit scaled up more than 3,500 times. By 2023’s third quarter, Ark expects five of the world’s largest fuel-cell trucks to be hauling concentrated zinc ore and finished ingots between a zinc refinery and the nearby port of Townsville. The carbon-free rigs will pack 50 kilos of hydrogen zapped from water using electricity from the refinery’s dedicated solar power plant.

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