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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."
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.
This is not that unusual for power plants. Some coal fired units are off as well, for example Dynegy's Wabash River is currently experiencing similar problems. Obviously this hurts everyone (the company loses generation during times when wholesale power prices are high and, if load gets too high, the consumer might experience brown outs or black outs). This problem will likely get worse as well as global warming takes hold.
Actually, it would be quite possible to do such a thing and you wouldn't even violate the second law of thermodynamics since you are only pumping the heat. One example of such a mechanism is the electrically powered fan on radiators in cars that improve cooling when the car is not moving.
However, it wouldn't change the problem: Where to dump the waste heat. Instead of pumping it in the river, you would be pumping it into the air, which may be better but you only shifted your waste disposal. Lastly, there is this slight technical problem that the waste heat of a nuclear power plant is enormous, usually around 2 GW, which would require a MASSIVE heat pump (i.e. "refrigerator"). That in turn would eat up a large portion of the generated electricity, greatly reducing efficiency.
As it turns out, however, an active heat pump isn't even needed to dump the heat into the atmosphere instead of pumping it into the river, usually that is accomplished with a cooling tower, though in this case there aren't enough available since the plant is not designed to run on towers alone.
Spelling matters.
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.
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.
t s.html
... Well you decide for yourself.
http://www.helsinginenergia.fi/en/tuotanto/benefi
US power stations are still only 40% efficient because
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No, dear, I did not. You are struggling with the Second Law of Thermodynamics, which — in the form most applicable to the situation — is spelled as "It is impossible to convert heat completely into work."
My point was, that a better-engineered reactor would convert more energy into work. This increase of the work/heat ratio is a purely engineering problem — the only "fundamental limit of thermodynamics" is that the ratio be below 1...
In Soviet Washington the swamp drains you.
Of course, you're welcome to study thermodynamic engineering and try to circumvent this issue yourself. If you manage to pull it off, you could make $Billions.
If the temperature of your cooling medium is 50 fahrenheit (280 Kelvin)
Your process can never be more than 47% efficient. No amount of engineering can change this fact.
Now if the temperature of your cooling medium rises to 90 fahrenheit, then you are stuck below 42%.
Thermodynamics not only says that the ratio must be below 1, it also says exactly by how much it must be below 1.
"Before air conditioning, yankees stayed in yankeeland. After air conditioning they moved to places where they weren't welcome."
Actually, refrigeration technology took off in the South before the North. The Yankees you so deride didn't need large plants to manufacture ice for their iceboxes, they had the Great Lakes.
As for electricity generation, you'll note that the New Deal and the Tennessee Valley Authority (TVA in TFA) was interested in improving electricity generation in the South long before consumer air conditioning was available, let alone viable. Southerners were interested in those new-fangled electric lights Northerners were beginning to take for granted.
"We used clothes lines to hang and dry our clothes, not electric driers."
Another technology that caught on in the South more than the North. It's not the North that has to deal with trying to dry clothes in 157% humidity, at least not year-round.
It's renewable in some sense, but not others. More specfically, big hydro genereally ends up not being sustainable:
fish spawning, methane, changes to the microclimate. On the other hand, we've not done enough with run-of-river.
Were that I say, pancakes?
fish spawning, methane and changes to the micro climate don't effect the dam's ability to generate electricity, so it is still renewable energy.
Renewable != earth loving hippy compatible.
What if Tetris was invented by Nazis?
Your open-cycle system will never be more efficient than a carnot cycle at the same temperatures.
I'm afraid Wonko's right. The total efficiency converges to Carnot's. If there is any *usable* waste heat left at the end of a cycle to put into another heat engine, then the first cycle wasn't running at full (reversible) Carnot efficiency.
BTW, if a heat engine were ever to be used in a closed system, then its efficiency would quickly converge to 0%, since the hot source would cool down and the cold source would heat up! The Carnot cycle, as I said in my other post, assumes infinite, constant temperature hot and cold sources, i.e. effectively the same as a system where heat is constantly added to the hot source (by a nuclear reactor) and taken away from the cold source (by a running river) to maintain a constant temperature.
What's purple and commutes? An Abelian grape.
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.
Never Politically Correct ~ I prefer the facts If you don't like what I say, get a life, or comment yourself.
Generally they don't transport steam, they transport hot but liquid water. See, engineers are not idiots. You must be new here.
Terrorists can't threaten a country's freedom and democracy. Only lawmakers and voters can do that.
You'd save money with solar if you had proper net metering. You don't need batteries in that case. Check http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html to see how things work in Georgia and Luisiana.
The reactor was shut down because the water exiting the plant's cooling system exceeded an average of 90 degrees F over a 24 hour period. The plants have an agreement with the state to limit the temperature of the water they put into the river. The water in the river is not even remotely 90 degrees F.
Brown's Ferry also just recently started one of its reactors after a long downtime, so this only kicked us back a few months. It's not a big impact to the nation's grid, not even to the local area.
As for why we don't recapture the energy in the heated water to make even more power, well, they just didn't think it was necessary back when we used to build power plants back in the 60's. Investing money in anything nuclear in the US is political suicide.