Shouldering The Nuclear Baseload
Nuclear power may be America’s most controversial source of energy. A dam can drown a stunning stretch of river. Coal may loom larger in climate and public health debates, given its airborne pollutants and toxins buried in coal-ash dumps dotting the nation. Solar-thermal plants, seen as environmentally benign, can incinerate birds in mid-flight. Using any technology has consequences, but with nuclear power, they feel more . . . consequential. It might be origins of nuclear power in the fires of World War II. It could be echoes of Chernobyl or Fukushima. Whatever the reason, bring up nuclear and you may generate heat that has nothing to do with physics.
The Nuclear Landscape
Whatever the opinions, these are the facts – 95 reactors at 57 plants in 29 states supply about 20% of America’s electricity. As mentioned earlier in this series, nuclear plants are baseload plants. They operate at maximum output nearly all the time, except when refueling or during maintenance. The oldest active reactor came online in 1969, the newest in 2016 – the latter the first such in 20 years. Two more reactors are now under construction in Georgia. And though we’re down from 107 units operating in 2003 –upgrades and more efficient refueling mean total output is about the same as it was 17 years ago. France remains the most nuclear-heavy country – more than 70% of its power comes from fission. But in terms of total output, the US still leads the world.
It’s all driven by physics on a scale that’s hard to grasp. Atoms of a few heavy, unstable elements like uranium are prone to split, or “fission”. In the process, they release neutrons – neutral subatomic particles – and huge amounts of energy. As those neutrons speed away, they hit other atoms. Some of them split, releasing more neutrons and more energy. That energy boils water, which generates steam, which turns a turbine – and so on into the grid. Under controlled conditions, you’re in the control room of a nuclear power plant as smokeless fire converts steam to electricity. Under uncontrolled conditions, you’re in the New Mexico desert on July 16th, 1945, as light brighter than the sun springs from the earth.
Keeping intense heat and potentially deadly radioactivity under control is an expensive, complex process. American reactors are surrounded by massive containment domes of concrete and steel. They’re cooled by networks of pumps and condensers backed up by multiply redundant systems in case of emergency or loss of power. And given their fuel, they’re operated to the most exacting standards in any industry in terms of security. All this adds up. It’s not that nuclear power is all that expensive in terms of routine operations, fuel and maintenance. EIA data show that between 2008 and 2018, these costs for fossil plants ranged from 3.5.to 4.1 cents per kilowatt-hour. For hydropower, it was .9 to 1.2 cents and for nuclear, ranging from 2.1 to 2.7 cents.
Up-Front Costs vs. Climate Benefits
What has tilted the table against nuclear projects in recent years has been costs – driven by this need for safety. An example: the Tennessee Valley Authority began construction on its Watts Bar plant in 1974. By the time a second reactor was done in 2016, total costs for the project hit $12 billion. “Abundance of caution” fits the industry’s outlook. After the Fukushima tsunami in 2013, new flood protection measures more than 6% to the costs of that second TVA reactor. And in Georgia, two new units for the Vogtle plant, first priced at $14 billion in 2009, are now estimated at $25.7 billion.
Despite high capital costs, nuclear power has one huge advantage over other forms of electricity in an era confronting climate limits. It produces power without producing CO2 or other greenhouse gases. Obviously, building plants and parts and refining fuel consume energy and generate greenhouse gases. But nuclear plants – with up to nearly 4 gigawatts of capacity, and operating flat-out for months on end – do so without any GHGs. With this in mind, there’s a big effort to extend the lives of nuclear plants now in service through the USDOE with improved materials, plant upgrades and risk analysis.
There’s been a great deal of time and money invested in developing the next generation of nuclear technology. We’re now in the fourth generation of plant designs, though none have gone beyond prototypes. Some designs use water at very high pressure, others use helium or molten salt as coolants. This next generation is designed to operate at higher temperatures, use much less fuel and generate way less waste. Some new designs can use nuclear waste as fuel. An additional important field is the development of passive safety designs – reactors that need no or minimal human intervention in emergencies.
Finally, given the high costs of nuclear, modular design is seen as the wave of the future. Smaller, more efficient reactors could allow for deployments of this form of low-carbon power without the enormous costs seen in current projects. Whether economic conditions and public opinion permit the deployment of this fourth generation will be one of the big climate/energy questions of the 2020s.