Nuclear power plant drops output by half: River too hot.

[SirNitram]

Link

Associated Press
Posted Aug 23, 2010 @ 07:55 PM
CHATTANOOGA, Tenn. —

The Tennessee Valley Authority has cut power generation in half at its largest nuclear plant to avoid overheating the Tennessee River in Alabama, costing the utility millions of dollars.

The Chattanooga Times Free Press reports the U.S.' largest public utility has already lost nearly $50 million in power generation at the Browns Ferry Nuclear Plant near Athens, Ala. Unless the summer cools down, TVA could lose more, pushing up fuel costs and consumer electric bills even after seven straight monthly increases.

TVA executives said the Browns Ferry Plant has operated at about half power for most of the past month and could remain slowed down through September.

TVA President Tom Kilgore said "all the radiant heat gets in the river when you have a summer as hot as this has been."

Among the nation's 66 nuclear plants, Browns Ferry has been the one hardest hit by concerns about overheated river water, according to the Nuclear Energy Institute and TVA. With three reactors, it is TVA's biggest nuclear facility.

TVA has reduced power production at Browns Ferry at least 39 days since July 8 because of the high river temperature.

Last week, TVA violated its permit with the Alabama Department of Environmental Management when the river temperature topped 90 degrees.

The cutback means TVA is losing 1,500 megawatts of power generation just when it's needed most.

For each day of 50 percent power at Browns Ferry, the utility spends more than $1 million extra to pay for replacement power, utility executives said.

The extra cost is added to ratepayer bills in the monthly fuel cost adjustment, which is up by more than 25 percent since March.

When the Tennessee River flows into the Guntersville Reservoir around Browns Ferry, the river widens and slows.

The plant draws in river water to cool its equipment, then releases it back into the river.

TVA uses mechanical draft cooling towers to help pull heat out of the cooling water before it is released.

Most U.S. nuclear plants are on an ocean or one of the Great Lakes or have closed-loop cooling systems that don't rely as much upon water from nearby rivers or lakes.

TVA's Watts Bar Nuclear Plant in Spring City has a closed-loop system. The Sequoyah plant near Soddy-Daisy uses less river water than Browns Ferry and has two cooling towers.

TVA also plans a closed-loop system with twin cooling towers at the Bellefonte plant planned in Hollywood, Ala.

Two coal-fired TVA plants at Cumberland, west of Nashville, and Colbert, near Muscle Shoals, Ala., have also had production slowdowns this summer -- but not as much as Browns Ferry.

During a public hearing before the TVA board last week, anti-nuclear activist Margaret Klein, of Knoxville, said nuclear plants are bound to encounter more thermal problems on the Tennessee River as global warming raises river temperatures.

While I'm not anti-nuclear, the lady is right: The planet is getting hotter, and that includes rivers. Nuclear power needs a price on carbon/pollution to keep viable. The only question is whether pro-nuke GOPers will wake up to this, or keep preaching the opposition to climate change legislation, or even it's existance.

[Sea Skimmer]

http://upload.wikimedia.org/wikipedia/c ... ry_NPP.jpg

It looks like this plant just doesn’t have a very good cooling setup in the first place. The French called out water cannons back in the 2003 heat wave to spray water on nuclear cooling towers. If this plant is loosing 1 million dollars a day I would think they’d try something similar.

The thermal efficiency of coal and nuclear plants is similar, so cooling requirements will also be similar for similar installed power. Its just nuclear plants tend to be very high power as far as power plants go. But coal can be plenty nuts on its own, just look at the British Ratcliffe Power Station.

On the other side of things gas turbines can approach twice the thermal efficiency of nuclear-coal and the plants are practical with smaller capacities meaning far more sites can work. Since a shift to all nuclear isn’t going to happen quickly even an ideal world we’ve got to try to ditch coal for gas ASAP. Gas turbine plants are pretty quick to build, and without huge masses of CO2 releasing cement production, and the carbon release is IIRC about 1/16th that of coal per unit of energy.

[Sarevok]

So what is the problem if the river heats up ? Is it purely ecological like killing fish or something more severe like eventually making river water less useful for cooling ?

[Serafina]

So what is the problem if the river heats up ? Is it purely ecological like killing fish or something more severe like eventually making river water less useful for cooling ?

The warmer the water, the less heat it can absorb. Hence, it is less usefull for cooling.

[Temujin]

So what is the problem if the river heats up ? Is it purely ecological like killing fish or something more severe like eventually making river water less useful for cooling ?

The warmer the water, the less heat it can absorb. Hence, it is less usefull for cooling.

Though I'm sure it can't be too good for the fish, amphibians, and other life that live in the river.

[Sea Skimmer]

Cooling installations are allowed to raise the water temperature to around 90 degrees F. That already kills some life and above all kills a lot of fish eggs; if they go any higher you’d end up with a dead zone for miles downstream. The cooling process does hit diminishing returns the hotter its intake water becomes, but that wouldn’t be very relevant on its own. The plant would only suffer minor thermal efficiency losses.

[RedImperator]

If I recall correctly, there was some controversy about expanding the Salem/Hope Creek complex in south Jersey for the same reason--possibly too much hot water being discharged into the Delaware.

[MKSheppard]

It looks like this plant just doesn’t have a very good cooling setup in the first place.

I recall reading that since the 1970s, nuclear power plants have moved away from giant natural draft cooling towers towards smaller mechanical draft cooling towers like in that photo, because the image of the large cooling tower is irrevokably linked with TMI and...Homer Simpson.

[Sea Skimmer]

I recall reading that since the 1970s, nuclear power plants have moved away from giant natural draft cooling towers towards smaller mechanical draft cooling towers like in that photo, because the image of the large cooling tower is irrevokably linked with TMI and...Homer Simpson.

Also just because mechanical cooling towers are cheaper up front, but you've got to pay to run the fans across the lifespan of the plant as well as the pumps any cooling system requires. Companies are fine with that since they really want to cut down on the massive up front construction cost of a nuclear plant. But the scale of the modern mechanical systems is pretty massive, and plenty of designs still use passive towers. That photo is showing cooling for no less then three reactors, and with very minimal holding areas for the water. Its no surprise its being hit very hard by a heatwave.

[AniThyng]

It looks like this plant just doesn’t have a very good cooling setup in the first place.

I recall reading that since the 1970s, nuclear power plants have moved away from giant natural draft cooling towers towards smaller mechanical draft cooling towers like in that photo, because the image of the large cooling tower is irrevokably linked with TMI and...Homer Simpson.

I've always wondered about that...the way it is portrayed in pop culture you'd think only nuclear plants use those huge curved cooling towers when that's not the case at all.

[His Divine Shadow]

I hate that, those towers look awesome. I remember driving past some in Germany and I so wish I had taken a photo.

[Temujin]

It looks like this plant just doesn’t have a very good cooling setup in the first place.

I recall reading that since the 1970s, nuclear power plants have moved away from giant natural draft cooling towers towards smaller mechanical draft cooling towers like in that photo, because the image of the large cooling tower is irrevokably linked with TMI and...Homer Simpson.

I've always wondered about that...the way it is portrayed in pop culture you'd think only nuclear plants use those huge curved cooling towers when that's not the case at all.

I remember having that same misconception as a kid; then I was shown a non-nuclear power plant with those same towers. Sadly most of the population with its anti-nuke hysteria will generally assume it's a nuke plant and react accordingly.

[The Duchess of Zeon]

There are ways to avoid the release of really hot water, anyway. My favourite is to build the nuclear complex next to a very large city and use the waste heat to provide central steam heat for the entire city. Many cities long had steam plants for all kind of heating, Seattle still has one downtown, and with sensible urban planning they still would, as otherwise all of that energy is just being wasted. You could provide central steam heat and even hot water to hundreds of thousands of people and hundreds of businesses in a given area, and you can use steam to power air conditioners for that matter. Anything we're venting in a river is within perfectly harmless levels of radiation for use in homes, or can be made so. Sadly such an implementation won't happen, but it would save massive quantities of energy to functional purposes while reducing costs for customers. Of course there's other ways we could eliminate that requirement, too.

[Sarevok]

Problem is what if your nuclear plant is located in a area with warm summers ? Like the aforementioned plant in Tennessee. People don't need to heat their homes in the summer at such locations.

[The Duchess of Zeon]

Problem is what if your nuclear plant is located in a area with warm summers ? Like the aforementioned plant in Tennessee. People don't need to heat their homes in the summer at such locations.

You can run air conditioning units off a heat source--I said that in my post.

[Sarevok]

Can you run existing air conditioners off steam ?

[Mr. Coffee]

Go on out to google maps and look at where the Browns Ferry plant is at. Don't be fooled by google saying it's west of Huntsville, that's just the local TVA/Huntsville Utilities depot. The actual plant in about 60 miles east of Huntsville along the Tennessee River about 15miles upstream from Decatur. The Plant is on the north bank, and as you'll notice it's way the fuck out in the middle of no where, so good luck getting the funding to lay the several hundred miles of pipes to get the waste heat water to anywhere it could be made useful.

If they'd put a little thought into reusing that waste heat like you're talking about, Marina, they'd have placed it the plant along the Tennessee somewhere around the 231/53 bridge south of Huntsville or along the south end of Redstone Arsenal along the river (Which would have made a fuckload more sense then sticking it clear out in Outer Redneckistan over by Athens).

[Beowulf]

Can you run existing air conditioners off steam ?

Existing ones? no. One's designed to run off steam? certainly. They'd have to be similar in design to a propane powered fridge.

[The Duchess of Zeon]

Can you run existing air conditioners off steam ?

There are very common refridgerator units called Absorption Refridgerators which use the process I'm referring too, but normal Compressor based refridgerators can't, unfortunately, which includes most air conditioning units, though absorption models are common enough in areas with unreliable electricity supplies.

Edit: Sorry, had entered this by the time you posted, Beo.

[Mr. Coffee]

Yeah, steam can be used to power a lot of shit, blah blah blah. The Brown's Ferry Plant is still to far away from anywhere large enough to make use of the waste heat from the cooling water to make running all the pipes worth it.

[aerius]

Yeah, steam can be used to power a lot of shit, blah blah blah. The Brown's Ferry Plant is still to far away from anywhere large enough to make use of the waste heat from the cooling water to make running all the pipes worth it.

They could build a massive greenhouse complex near the plant and use the steam to heat the greenhouses. You could grow grow a billion bucks worth of weed in there and that'll pay for everything in a less than a year.

Unfortunately that's illegal, so they'll have to grow tomatoes and watermelons or something.

[Sea Skimmer]

Well big mistake on my part, that picture I posted above is only showing one sixth of the cooling towers. But that still doesn’t strike me as all that much for over six gigawatts of heat, seems the plant was up rated in service too, which might mean needing to cut back power in extreme hot weather was just an accepted limitation. It’s located on a small reservoir, so not much flow of water passes by.
http://blog.al.com/spotnews/2009/02/lar ... 0plant.jpg

The ideal thing to do would be to build some kind of specialist chemical refinery on the site that can use waste heat as process heat. But it’d probably just be cheaper and easier to add another set of dry cooling towers as an auxiliary loop. Its not like that isn't an option, California and New York State have both moved to force a number of power plants and refinery operations to convert to dry cooling only.

[The Duchess of Zeon]

Co-locating chemical facilities to use waste heat as process heat would be awesome. I'm kicking myself for not thinking of that one before. It's certainly actually viable, unlike the politically unacceptable idea of building nuclear reactors within urban areas (Sadly).

[The Duchess of Zeon]

Yeah, steam can be used to power a lot of shit, blah blah blah. The Brown's Ferry Plant is still to far away from anywhere large enough to make use of the waste heat from the cooling water to make running all the pipes worth it.

Very true, and I suppose I got carried away and wasn't really talking about anything applicable to this plant. Skimmer's co-location of a chemical refinery however, is an eminently practical idea... if the appropriate investors could just be sold on it. It would certainly be a very competitive facility as the heat available would be quite cheap as it would be wasted (and potentially cause these sorts of reductions in energy generation potential) otherwise.

[Temujin]

It's still a great idea, it's just sad that we rarely see even a fraction of that kind of forethought go into city planning in the real world.