State News

Drought Could Force Nuclear Plants to Shut Down

Posted January 23, 2008

— Nuclear reactors across the Southeast could be forced to throttle back or temporarily shut down later this year because drought is drying up the rivers and lakes that supply power plants with the awesome amounts of cooling water they need to operate.

Utility officials say such shutdowns probably wouldn't result in blackouts. But they could lead to shockingly higher electric bills for millions of Southerners, because the region's utilities could be forced to buy expensive replacement power from other energy companies.

Already, there has been one brief, drought-related shutdown, at a reactor in Alabama over the summer.

"Water is the nuclear industry's Achilles' heel," said Jim Warren, executive director of North Carolina Waste Awareness and Reduction Network, an environmental group critical of nuclear power. "You need a lot of water to operate nuclear plants." He added: "This is becoming a crisis."

An Associated Press analysis of the nation's 104 nuclear reactors found that 24 are in areas experiencing the most severe levels of drought. All but two are built on the shores of lakes and rivers and rely on submerged intake pipes to draw billions of gallons of water for use in cooling and condensing steam after it has turned the plants' turbines.

Because of the yearlong dry spell gripping the region, the water levels on those lakes and rivers are getting close to the minimums set by the Nuclear Regulatory Commission. Over the next several months, the water could drop below the intake pipes altogether. Or the shallow water could become too hot under the sun to use as coolant.

"If water levels get to a certain point, we'll have to power it down or go off line," said Robert Yanity, a spokesman for South Carolina Electric & Gas Co., which operates the Summer nuclear plant outside Columbia, South Carolina

Extending or lowering the intake pipes is not as simple at it sounds and wouldn't necessarily solve the problem. The pipes are usually made of concrete, can be up to 18 feet in diameter and can extend up to a mile. Modifications to the pipes and pump systems, and their required backups, can cost millions and take several months. If the changes are extensive, they require an NRC review that itself can take months or longer.

Even if a quick extension were possible, the pipes can only go so low. It they are put too close to the bottom of a drought-shrunken lake or river, they can suck up sediment, fish and other debris that could clog the system.

An estimated 3 million customers of the four commercial utilities with reactors in the drought zone get their power from nuclear energy. Also, the quasi-governmental Tennessee Valley Authority, which sells electricity to 8.7 million people in seven states through a network of distributors, generates 30 percent of its power at nuclear plants.

While rain and some snow fell recently, water levels across the region are still well below normal. Most of the severely affected area would need more than a foot of rain in the next three months - an unusually large amount - to ease the drought and relieve pressure on the nuclear plants. And the long-term forecast calls for more dry weather.

"If we don't get at least 10-to-15 inches of rainfall in January, February and March, lake levels could be lower in the fall of 2008 than they were in 2007 - and that could be a disaster," said Donna Lisenby, executive director of Catawba Riverkeeper, environmental group that monitors Lake Norman and other lakes along the 225-mile Catawba River system.

Lake Norman near Charlotte is down to 93.7 feet - less than a foot above the minimum set in the license for Duke Energy Corp.'s McGuire nuclear plant. The lake was at 98.2 feet just a year ago.

"We don't know what's going to happen in the future. We know we haven't gotten enough rain, so we can't rule anything out," said Duke spokeswoman Rita Sipe. "But based on what we know now, we don't believe we'll have to shut down the plants."

At Progress Energy, which operates four reactors in the drought zone, officials warned in November that the drought could force it to shut down its Harris reactor near Raleigh, according to documents obtained by the AP. The water in Harris Lake stands at 218.5 feet - just 3 1/2 feet above the limit set in the plant's license. Those comments were made, however, when the level of the lake was a foot lower than it stands now.

Caren Anders, the Raleigh-based company's vice president of transmission, operations and planning, told the Nuclear Regulatory Commission that if the water level fell below the limit at Harris -- 214 feet -- the company would shut down that plant and "purchase power or redispatch generation to conserve the water and to meet our environmental limits."

But Harris spokesman Rick Kimball said Wednesday that there are no concerns about a shutdown. The water from Harris Lake is used to turn the wheels that cool the reactor, he said. Water used inside the plant comes from a completely different source that will never be in jeopardy, Kimball added.

During Europe's brutal 2006 heat wave, French, Spanish and German utilities were forced to shut down some of their nuclear plants and reduce power at others because of low water levels - some for as much as a week.

If a prolonged shutdown like that were to happen in the Southeast, utilities in the region might have to buy electricity on the wholesale market, and the high costs could be passed on to customers.

"Currently, nuclear power costs between $5 to $7 to produce a megawatt hour," said Daniele Seitz, an energy analyst with New York-based Dahlman Rose & Co. "It would cost 10 times that amount that if you had to buy replacement power - especially during the summer."

At a nuclear plant, water is also used to cool the reactor core and to create the steam that drives the electricity-generating turbines. But those are comparatively small amounts of water, circulating in what are known as closed systems - that is, the water is constantly reused. Water for those two purposes is not threatened by the drought.

Instead, the drought could choke off the billions of gallons of water that pass through the region's reactors every day to cool used steam. Water sucked from lakes and rivers passes through pipes, which act as a condenser, turning the steam back into water. The outside water never comes into direct contact with the steam or any nuclear material.

At some plants - those with tall, Three Mile Island-style cooling towers - a lot of the water travels up the tower and is lost to evaporation. At other plants, almost all of the water is returned to the lake or river, though significantly hotter because of the heat absorbed from the steam.

Progress spokeswoman Julie Hahn said the Harris reactor, for example, sucks up 33 million gallons a day, with 17 million gallons lost to evaporation via its big cooling towers. Duke's McGuire plant draws in more than 1 billion gallons a day, but most of it is pumped back to its source.

Nuclear plants are subject to restrictions on the temperature of the discharged coolant, because hot water quickly evaporates and can also kill fish or plants or otherwise disrupt the environment. Those restrictions, coupled with the drought, led to the one-day shutdown August 16 of a TVA reactor at Browns Ferry in Alabama.

The water was low on the Tennessee River and had become warmer than usual under the hot sun. By the time it had been pumped through the Browns Ferry plant, it had become hotter still - too hot to release back into the river, according to the TVA. So the utility shut down a reactor.

"When the river temperature rises, even with the cooling towers in operation, the only way to keep from exceeding temperature is to reduce power or shut down a unit," said TVA spokesman John R. Moulton.

David Lochbaum, nuclear project safety director for the Union of Concerned Scientists, warned that nuclear plants are not designed to take the wear and tear of repeatedly stopping and restarting.

"Nuclear plants are best when they flatline - when they stay up and running or shut down for long periods to refuel," Lochbaum said. "It wears out piping, valves, motors."

Both the industry and federal regulators reject that concern. Scott Burnell, a spokesman for the Nuclear Regulatory Commission, said plants can shut down and resume operations quickly without problems. The agency has on-site inspectors to ensure utilities are following safety regulations, he said.

That's little comfort to Lisenby. With temperatures in the low 30s on Monday, she launched her boat in Lake Norman and headed for McGuire's intake pipes, where the water temperature was 51 degrees. In the plant's 3,500-acre discharge area, the water was 71 degrees - so warm that misty puffs of vapor hovered near the water's surface before dissipating in the wind.

"If Duke Energy is asking everyone to conserve energy, why doesn't Duke Energy have the most modern technology to save as much water as possible? Why don't they properly cool their water?" she asked. "If water levels get too low, this plant will have to shut down."

37 Comments

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  • blondton13 Jan 23, 6:01 p.m.

    Lovely news. Think it's about time to step away for a bit. It's getting me down. :(

  • TechRescue Jan 23, 5:57 p.m.

    Heated salt water is extremely corrosive, especially at the high velocities required at Nuc plants - you'd have more problems with pipe erosion than corrosion. Nuclear subs get away with it because they're in the water - they can use lots and lots of slow moving water - our quietest subs, for example are cooled by convection (warm water rises).

    People like Jim Warren just want to complain and control - they don't have a solution. BANANAS (Build Absolutely Nothing Anywhere Near Anything, Stupid) is more the rule of the day than NIMBY. If we'd all just go back to the Pioneer days - Oh wait, burning wood and horse manure contribute to global warming as well.

    Don't worry - Hillary or Barack will fix everything - just don't expect to have any money left when they're done..

  • whatelseisnew Jan 23, 5:30 p.m.

    And the good news just keeps rolling in. So that big ole check the Feds are sending. So far a chunk of it will go to Wake County in December for higher property tax. Guess if there is any left I better keep it to send on in to the power company. But there is good news in this. The state taxes are electric bills so we can contribute more money to them as well. Maybe we can get some of that methane from belching cows and use it to generate electricity.

  • USA Jan 23, 5:17 p.m.

    OMG, do you really believe this could happen? This is nothing more than a pathetic scare tactic being used by state and local officials who failed to realize a problem before it became reality. You don't bring a Nuclear Power Plant on-line overnight...the same goes for its shutdown. I see an ID10T error here.

  • drewbyh Jan 23, 5:15 p.m.

    @Chuck U Farley - Settle down there dude. The coriolis force is caused by the earths rotation and temperature variations not the other way around. The rotation of the earth can not be slowed due to atmospheric drag.

  • smitty Jan 23, 5:12 p.m.

    http://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt

  • Riddickfield Jan 23, 5:05 p.m.

    "Can someone explain where the water is actually used in a nuclear plant. I thought the water that is heated to produce steam is in a closed loop, and the cooling water just came out a little hotter than it went it. Obviously some is lost as steam because we've all seen the "radioactive smoke" coming out of the cooling tower, but how much is actually lost?"

    Yes, typically the power plant brings in water from a river or lake for cooling water. Some plants use this to make up for the water lost to evaporation which is what you see coming out of the cooling tower... such as at the harris plant. Others just use the lake as a cold well, take in cold water from the lake, discharge warmer water back in.

    Either way, if the lake level drops below your intake pipe level you cannot cool your plant and have to shut it down.

  • Chuck U Farley Jan 23, 4:49 p.m.

    I'm sick of people touting wind power. Wind is created by the coriolis force, which is a result of the earth's rotation. If we cover the earth in wind turbines, we are going to slow down its rotation. You think greenhouse gasses are bad, imagine the global warming and droughts that would be created by a 48-hour day!

  • linnway Jan 23, 4:41 p.m.

    OK, this may be a totally stupid question, and I may come off as looking lik ean idiot, but I am not familiar with this particular area...um, we have an ocean 2 hours away. Can't something be done to ocean water to make it be useful for something?!?! With today's technology? Or did I just make a BleeP out of myself for suggesting that?!?!?!

  • redant Jan 23, 4:36 p.m.

    Interesting observation by Jim Warren of NC WARN (anti-nukes). "Water is the nuclear industry's Achilles' heel," said Jim Warren, executive director of North Carolina Waste Awareness and Reduction Network, an environmental group critical of nuclear power. "You need a lot of water to operate nuclear plants." He added: "This is becoming a crisis." If it is going to become a crisis then alternate plants at oceanfront would seem to be a plausible solution.

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