Why the lifetime of nuclear plants is getting longer

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Aging can be scary. As you get older, you might not be able to do everything you used to, and it can be hard to keep up with the changing times. Just ask nuclear reactors.

The average age of reactors in nuclear power plants around the world is creeping up. In the US, which has more operating reactors than any other country, the average reactor is 42 years old, as of 2023. Nearly 90% of reactors in Europe have been around for 30 years or more.

Older reactors, especially smaller ones, have been shut down in droves due to economic pressures, particularly in areas with other inexpensive sources of electricity, like cheap natural gas. But there could still be a lot of life left in older nuclear reactors.

The new owner of a plant in Michigan that was shut down in 2022 is now working to reopen it, as I reported in my latest story. If the restart is successful, the plant could operate for a total of 80 years. Others are seeing 20-year extensions to their reactors' licenses. Extending the lifetime of existing nuclear plants could help cut emissions and is generally cheaper than building new ones. So just how long can we expect nuclear power plants to last?

In the US, the Nuclear Regulatory Commission (NRC) licenses nuclear reactors for 40-year operating lifespans. But plants can certainly operate longer than that, and many do.

The 40-year timeline wasn't designed to put an endpoint on a plant's life, says Patrick White, research director at the Nuclear Innovation Alliance, a nonprofit think tank. Rather, it was meant to ensure that plants would be able to operate long enough to make back the money invested in building them, he says.

The NRC has granted 20-year license extensions to much of the existing US nuclear fleet, allowing them to operate for 60 years. Now some operators are applying for an additional extension. A handful of reactors have already been approved to operate for a total of 80 years, including two units at Turkey Point in Florida. Getting those extensions has been bumpy, though. The NRC has since partially walked back some of its approvals and is requiring several of the previously approved sites to go through additional environmental reviews using more recent data.

And while the oldest operating reactors in the world today are only 54, there's already early research investigating extending lifetimes to 100 years, White says.

The reality is that a nuclear power plant has very few truly life-limiting components. Equipment like pumps, valves, and heat exchangers in the water cooling system and support infrastructure can all be maintained, repaired, or replaced. They might even get upgraded as technology improves to help a plant generate electricity more efficiently.

Two main components determine a plant's lifetime: the reactor pressure vessel and the containment structure, says Jacopo Buongiorno, a professor of nuclear engineering at MIT.

• The reactor pressure vessel is the heart of a nuclear power plant, containing the reactor core as well as the associated cooling system. The structure must keep the reactor core at a high temperature and pressure without leaking.

• The containment structure is a shell around the nuclear reactor. It is designed to be airtight and to keep any radioactive material contained in an emergency.

Both components are crucial to the safe operation of a nuclear power plant and are generally too expensive or too difficult to replace. So as regulators examine applications for extending plant lifetimes, they are the most concerned about the condition and lifespan of those components, Buongiorno says.

Researchers are searching for new ways to tackle issues that have threatened to take some plants offline, like the corrosion that chewed through reactor components in one Ohio plant, causing it to be closed for two years. New ways of monitoring the materials inside nuclear power plants, as well as new materials that resist degradation, could help reactors operate more safely, for longer.

Extending the lifetime of nuclear plants could help the world meet clean energy and climate goals.

In some places, shutting down nuclear power plants can result in more carbon pollution as fossil fuels are brought in to fill the gap. When New York shut down its Indian Point nuclear plant in 2021, natural gas use spiked and greenhouse gas emissions rose.

Germany shut down the last of its nuclear reactors in 2023, and the country's emissions have fallen to a record low, though some experts say most of that drop has more to do with an economic slowdown than increasing use of renewables like wind and solar.

Extending the global nuclear fleet's lifetime by 10 years would add 26,000 terawatt-hours of low carbon electricity to the grid over the coming decades, according to a report from the International Atomic Energy Agency. That adds up to roughly a year's worth of current global electricity demand. That could help cut emissions while the world expands low-carbon power capacity.

So when it comes to cleaning up the power grid, there's value in respecting your elders, including nuclear reactors.

Now read the rest of The SparkRelated reading

A nuclear power plant in Michigan could be the first reactor in the US to reenter operation after shutting down, as I wrote in my latest story.

Germany shut down the last of its nuclear reactors in 2023 after years of controversy in the country. Read more in our newsletter from last April.

The next generation of nuclear reactors is getting more advanced. Kairos Power is working on cooling its reactors with salt instead of pressurized water, as I reported in January.

Another thing

A total solar eclipse will sweep across the US on Monday, April 8. Yes, it will affect solar power, especially in states like Texas that have installed a lot of solar capacity since the 2017 eclipse. No, it probably won't be a big issue for utilities, which are able to plan far in advance for the short dip in solar capacity. Read more in this story from Business Insider.

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