As if Nuclear Power Wasn't Dangerous Enough, Now Nukes Have Found A Worse Enemy: Drought
Drought Endangering Nuclear Power
Thursday, Jan. 24, 2008 By MITCH WEISS/AP
http://www.time.com/time/nation/article/0,8599,1706555-1,00.html
(LAKE NORMAN, N.C.) — 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 may 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 N.C. 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, S.C.
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.
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.
At Progress Energy Inc., 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.
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.
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."
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