Heat Wave Shuts Down Alabama Reactor

mdsolar writes "In a first for the US, one of three nuclear reactors at the Browns Ferry nuclear plant in Alabama has been shut down because the Tennessee River is too hot to provide adequate cooling for the waste heat produced by the reactor. This is happening as the TVA faces its highest demand for power ever, reports the Houston Chronicle. This effect has been seen in Europe in the past, forcing reduced generation, but the US has until now been immune to the problem. The TVA will buy power elsewhere and impose higher rates, blaming reduced river flow as a result of drought."

In Soviet Russia

In Soviet Russia, overheating nuclear reactor [wikipedia.org] shuts down YOU!

Meanwhile Back In Alabama

A little noted fact of the cold war is that a very large amount of the US total electrical generation capacity is in the TVA region (Tennessee River - Dependent) The loss of this reactor is serious as the whole USA has no reserve capacity at peak load and with the heat wave over the East USA this is a critical loss. If it were the only reactor in danger this might be of no concern. The US TVA operates 5 big reactors and numerous coal fired plants all of which have the Tennessee River at thermal capacity to cool them and the river is dropping daily.

If heavy sustained rain does not fall on the Tennessee River Valley over the next 3 to 4 months an event which is historically unlikely, the loss of something close to 15 times the Browns Ferry reactor in capacity is likely to hit the USA. There is nothing to pick up the load. The loss of this one reactor is nearly equal to all the wind energy the USA generates. This loss threatens the operations of every one of the 48 US States. With the possible loses in Alabama Power pools and their reactors etc as well as Georgia Power, this poses the very real risk of cutting the energy supply of the USA by a very large fraction. As I write the North Alabama region is short 60 inches of rain over the past 18 months. The US TVA has been drawing down storage for 5 years now. There is no reserve and little prospect of one for some years to come.

I had warning of this imminent event when the City of Huntsville requested from TVA more water for its treatment plant and was turned down for supply. I knew then that the supply was gone.

Re:Meanwhile Back In Alabama

Huh. Gosh. See, if we'd invested in a MIX of power instead of depending so heavily on coal and nuclear (which the industry is trying to bump up in significance), we wouldn't be facing such a predicament.

Germany has wisely seen fit to invest one-seventh of its power money in wind energy. And it has legislated, and many Germnans have benefited for years already, from a solar-energy subsidy.

Too bad we don't have uncorrupted, uncronyed leadership in the US with the courage and vision to diversify the energy portfolio. Pay now or pay MUCH MUCH more later.

Nuke-lovers are always griping that wind-energy is too unreliable. Huh, guess what?

Re:Meanwhile Back In Alabama

TFA has the engineering wrong. The problem isn't the river temperature as much as the air temperature. A nuclear power plant needs to be located near a river so it can have a large supply of relatively cool water to use as a working fluid. The river water gets boiled into steam by reactor water in the nuclear reactors primary coolant loop. This is steam is what turns the turbines and generates the electricity. When it exits the turbines it's still steam, it's just cooler and wetter. You can't return it in this state because doing that would dramatically raise the river's temperature. You have to cool it down before you can put it back. To do that you use a passive air to water heat exchanger. But they're having a heatwave down there. Between the starting temperature of the river and the reduced efficiency of the passive heat exchanger using all three reactors in the plant would heat the river to unacceptable levels.

Unacceptable is not boiling it's probably something in low 90F range because if the mean temperature of the river was over 90F for any period of time you raise the risk of algae blooms and fish kills.

Physical conditions are not preventing the plant from running, environmental considerations are. And if the river's temperature is close to or exceeds the contracted discharge temperature without being heated by the plant then reevaluating the environmental decision may be in order.

-- Ecks

Re:In Soviet Russia

Soviet Russia doesn't refer to USSR. It's to distinguish it from Tsarist Russia, or Kievan Russia, or any of the other regimes that ruled Russia. Similar usages in other countries: Napoleonic France, Imperial Rome, Colonial America, Nazi Germany.

Re:In Soviet Russia

Actually, it's to distinguish it from Russia now. The original joke just said Russia, it was only after the collapse of the USSR that it changed.
There's not really much worry about people think the jokes are about Tsarist Russia is there?

(After writing this bit, it bacame clear to me that subconciously, I envision 1st Dude to be Brian Griffin, and 2nd Dude to be Stewie.)
1st Dude: "In Russia overheating reactor shuts down YOU."
2nd Dude: "Oh yea, thats funny, I get it, cos like, they just used uranium for yellow pottery glave back in Tsarist times right? Thats funny. No wait, Don't get that, that makes no sense"
1st Dude: "No, like I mean the Soviet era, like Chernobyl blowing up"
2nd Dude: "oh right, like why didn't you say"
1nd Dude: "I dunno, I figured it was obvious"
2nd Dude: "wasn't umm wasn't Chernobyl in the Ukraine"
1st Dude: "What am I like, a geography teacher now?"
2nd Dude: "that's like pretty poor taste man, a lot of people died"
2nd Dude: "That's not really funny at all"
1st Dude: "In Soviet Russia, taste poors YOU! heh heh"
2nd Dude: "that one wasn't even a sentence"

not immune

>but the US has, until now, been immune to the problem.
no, not immune. it just hasn't happend until now.

Reasons right?

I work at a nuclear power plant. We have a limit for the temperature of the river downstream of our returned cooling water for environmental reasons, not reasons related to the power generation process. I suspect the TVA has a similar requirement.

I noted from the nrc website (www.nrc.gov) that their other reactors are operating at reduced load, which is what our reactors must do to limit the heat input into the river.

So this is nothing remarkable.

Re:Reasons right?

I see those huge cooling towers and water cooling systems .. and I have to wonder ...

How efficient is a power generation plant that throws away gigawatts of power as waste heat?

Isn't it about time you find a more efficient way to generate power, turbines and generators that don't waste so much heat that we just went to all that trouble to make in the first place?

I don't expect 100% efficiency, but what we're doing now is crazy.

Re:Reasons right?

Physics: It's not just a good idea, it's the law [wikipedia.org].

Some people sell their "waste" heat

To heat domestic water, space heating and even to power adsorption chillers which can reduce AC requirements. Even coal power stations can hit 88% efficient.

http://www.helsinginenergia.fi/en/tuotanto/benefit s.html [helsinginenergia.fi]

US power stations are still only 40% efficient because ... Well you decide for yourself.

 

Re:Some people sell their "waste" heat

Some people sell their "waste" heat
To heat domestic water, space heating and even to power adsorption chillers which can reduce AC requirements.

Try selling the US public on steam heat from a nuke. Yes, the coolant loop neither touches the core nor picks up radioactive ions, but see if you can get the unwashed masses to believe they'll be safe with it!

Re:Some people sell their "waste" heat

Even more unlikely, try selling people on the idea of placing nuke plants in large metropolitan areas so they can buy piped in heat from the plant.

Now if you presented to the American public with the word "free" heat, then we might get something going.

Re:Reasons right?

How efficient is a power generation plant that throws away gigawatts of power as waste heat?

From the heat source to electrical power output is usually in the range 35--50%, depending on the plant design. A fundamental problem is the theoretical limit of the efficiency of a heat engine, a device that converts a temperature difference into mechanical power. It is 1 - Tcold/Thot, where Tcold and Thot are the temperatures of the cold and hot parts, in kelvin. For a steam-operated heat engine, the cold end is around the boiling point of water (373 K), and the hot end might be 1000 K, which limits the efficiency to 63% if there are no other losses. But one can use the waste heat for other purposes in a cogeneration plant [wikipedia.org], for example for residential heating in cold climates or for the industry.

Re:Reasons right?

Nope. You can't beat http://en.wikipedia.org/wiki/Carnot_cycle [wikipedia.org] in efficiency. The practical upper limit for nuclear power plants is about 50%. And we're already getting closer to this limit.

We can use some insane things like high temperature (thousands degrees) reactors with gas cooling to get another 10%-15% of efficiency, but it is just not practical.

Re:paddle wheels in the heat stream

Are you thinking a forest of insulated two-foot steam pipes running all around town? Sounds pretty ugly, noisy, expensive and environmentally disruptive.

Here in Sweden we've had this in the cities forever. It's not ugly, noisy, expensive and environmentally disruptive. Instead it's underground.

Generally they don't transport steam, they transport hot but liquid water.

See, engineers are not idiots.

You must be new here.

River too hot?

Why not just run the river through a refrigerator to cool it down? After all, you can generate the electricity for the refrigerator in the plant.

(I'd patent the idea, but the patent office has a silly rule regarding perpetual motion machines that gets in the way...)

TVA net metering policy

The cooling problem is a result of TVA's interest in building more reactors. Browns Ferry is now operating with two reactors instead of three because they recently added a reactor. They are also planning on adding a reactor upstream at Watts Bar http://www.tva.gov/news/releases/julysep07/wbu2.ht m [tva.gov] adding to the heat load on the Tennessee River. So, next time, they may have to take two Browns Ferry reactors off line at seasonal peak demand. This makes electricity more expensive because it requires buying rather than selling electricity when it is most expensive.

But, the fairly natural solution to the problem, reducing summer demand through net metering of customer generated solar power, a solution being implemented in 41 states and DC, is hampered in the TVA service territory by TVA's net metering policy: http://www.tva.gov/purpa/net_metering.htm [tva.gov] which is a billing period-by-billing period policy rather than an annual carryover policy used in net metering states. Adopting a reasonable net metering policy would allow TVA to become a summer time peak demand power exporter and gain by arbitrage, reducing the risk of higher overall rates it is building for itself by not paying attention to the capacity of the river system to handle the 60% of wasted energy nuclear power generation creates.
--
Power when you want it most: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html [blogspot.com]

Renewables question....

Interesting in the article that the journalist doesn't include power generated by hydroelectric dams as renewable energy...

"TVA gets about 60 percent of its electricity from coal-fired power plants, 30 percent from nuclear plants and 10 percent from its 29 hydroelectric dams. Renewable energy sources such as wind and solar account for less than 1 percent."

Any idea why that might be? Political slant? ignorance?

Umm, I mean the water flows through the dam, it goes out to sea, it evaporates, and it rains back up in the mountains and comes through the dam again. Seems pretty renewable to me.... at least some of it is coming back up through that cycle if not all...

It is about boiling rivers

It ain't about problems with the cooling itself, for that the rivers would need to be far hotter. The problem is enviromental, if you add extra heat to an already warm river you risk that it rises to the point were you destroy the eco-system. Simply put, the fishes get cooked and the algea grow out of control.

This is considered to be a bad thing.

Re:Waste heat?

If only it were that simple.

Imagine one of those old-style water wheels. Your question is akin to asking, "Why not figure out a way to use the energy of that flowing water without wasting it by allowing it to flow away?"

Re:What "waste heat"?

In practice this is an engineering problem

You misspelled "fundamental limit of thermodynamics"

Re:This is actually really good news

s/ice cold beer/frosty piss/

If the beer's Bud, don't bother - there's no difference.

The overly-simplified solution

Eliminate nuclear and coal power in favor of solar and wind power, and replace the stupid cars with bikes.

The bicycle as a commuter vehicle works only under ideal conditions and only for the young and fit. You won't be taking a bicycle into Buffalo, NY in mid-winter. You won't be taking a bicycle into Houston, TX in mid-summer.

Re:Air conditioning ruined the South

"The South never had a "carbon footprint" before yankee glutons moved to Miami and Atlanta."

It sure burned the heck out of wood, Bo! The spelling is "Yankee gluttons", BTW.

"Most of us grew up without air conditioning and were happy that way. We used clothes lines to hang and dry our clothes, not electric driers. Life was good."

HAHAHAHA! When I see local folks volunteering to go back to an AC-free life I'll buy the connection between "no AC" and "happiness".
I still use clothes lines to dry clothes (clothes smell fresher besides the energy savings), but there is good reason AC is popular among non-Yankees. I don't see any nostalgia for doing washing in wooden tubs and ironing it with (aptly named) "sad irons" either. The tubs are planters and the irons are doorstops, the shotgun shacks whose layout helped somewhat with cooling are empty, and (most) of the people don't look the the folks in a James Agee book.

I'm a "Damn Yankee" (the ones that came and stayed) myself, though I'm far more genuinely countrified (and right wing) than most locals.

If you wanted to keep out the sort of Yankees that wouldn't fit, not selling them everything at fire-sale prices would have done it. The Southeast got rich and is getting richer by urban and suburban sprawl, so if ya want things the way they used to be, move into the Deep South and away from the coast.