TVA Shuts Reactors: River Water is Too Hot
by Lloyd Alter, Toronto 
on 08.17.07
In the middle of a heat wave, the Tennessee Valley Authority has been forced to shut down a reactor at Browns Ferry. because water drawn from the Tennessee River was exceeding a 90-degree average over 24 hours, amid a blistering heat wave across the Southeast. "We don't believe we've ever shut down a nuclear unit because of river temperature," said John Moulton, spokesman for the Knoxville, Tenn.-based utility. They are buying power elsewhere and was already imposing a surcharge because of lower hydroelectric power production caused by drought conditions.
This was discussed in an earlier post: ""We're going to have to solve the climate-change problem if we're going to have nuclear power, not the other way around. As the climate warms up, nuclear power plants are less able to deliver." Same is true of coal fired plants, and we are getting lots more of those. " ::Houston Chronicle
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Often when it is very hot, the wind doesn't blow much either, which obviously reduces wind turbine output.
All large scale power plants except hydro (dams) depend on a large cooling source - generally a river, ocean, or large lake. Coal plants, gas plants, nuclear - it doesn't matter. One of the things that is different with nuclear is there are a lot stricter guidelines on operating a plant with a hotter than normal cooling source-- both for safety reasons and because the power generating equipment (not the nuclear stuff) costs a lot of money and you want to operate it as designed. Some of this cooling problem can be resolved via additional localized cooling ponds, etc. Units using the ocean as a cooling source should not have this problem.
This is not to say that nuclear is the energy solution. Nature's checkbook is hard to blance, and there are no real "solutions" in the energy biz - just choices and tradeoffs.
If you'd like to examine large scale power production and the US nuclear industry in an entertaining fashion, see my novel "Rad Decision", available at no cost to readers at my website and also in paperback. I've worked in the nuke industry for over two decades after studying alternative energy in college. RadDecision.blogspot.com
In many cases the thermal doischarge limit is a permit condition imposed at a particular level needed to support fish and aquatic life populations. These temp limits were typically set back in the mid 1970's , in an "Earth Day I" atmosphere, based on a great deal of expensive studies of native organisms in the receiving water.
A right wing enough or desperate enough Federal government, egged on by brownout-frustrated consumers, could easily be tempted to over-ride those permit conditions at the next relicensing hearing. Dangerous times are ahead.
Where on the river do they get their water?The surface water would be warmer.But from the bottom it would be cooler.What about a deep well?Water from the ground is about 55 degrees centigrade.That should be cold enough.The water would only be recycled back into the river.Would that not work?
its super hot here and it sucks
'Anonymous', most cooling intakes are already at the bottom of the river, and groundwater wells could never supply the volume of water needed without significant ecological side-effects, as well as much much higher costs for pumping.
Of course, if plants are responsibly designed to utilize as much dry-cooling as possible (cooling towers), then river temperature will be less important, as much less water will be required by the plant.
Aj
55 Centigrade is 131 in Fahrenheit
I think you where try to say 55 Fahrenheit and got them mix up I hope
55 Centigrade is 131 in Fahrenheit.
I think you where trying to say 55 Fahrenheit and got them mix up, I hope.
Pulling water from a well type solution wouldn't provide enough water to cool most nuclear facilities. The usual amount of water used by these facilities is measured in hundred if not thousands of gallons per minute. Even if an underground aquifer could be located nearby the power consumption to get that water to the reactor cooling chamber and then back would be greater than the current method of using some of a nearby river's supply of water.
The general method used by these facilities is to pull water from upstream of the reactor using the waters motion to start the process and a gravity feed to continue it. The byproduct is released downstream from the reactor to allow it to cool some. Testing is done at a predetermined distance from there, and depth in the river, to determine if the natural ecosystem is being threatened by the process.
They need cool water to cool the condensers leading out from the steam turbines. Regardless of whether the water is cooler further down or not, the plant can't suddenly be built to access water from another depth. And in any case, it can't possibly be good for the ecology of the river for the plant to tap into the one last cool refuge for any river life trying to escape the heat.
They need cool water to cool the condensers leading out from the steam turbines. Regardless of whether the water is cooler further down or not, the plant can't suddenly be built to access water from another depth. And in any case, it can't possibly be good for the ecology of the river for the plant to tap into the one last cool refuge for any river life trying to escape the heat.
The issue is not that it can't operate under these conditions. The issue is that the operating license doesn't cover operation under these conditions.
They could evaluate operation with higher water temperatures, at at worst, require operation at a lower power under those conditions.
" Where on the river do they get their water?The surface water would be warmer.But from the bottom it would be cooler.What about a deep well?Water from the ground is about 55 degrees centigrade.That should be cold enough.The water would only be recycled back into the river.Would that not work? "
I used the wrong term i apologize.On my property is an old gravel quarry.They hit a natural spring when digging.It filled the hole overnight.The water is extremely cold.We do not swim in it for that reason.We also dug a pond farther out back in the woods.A small creek from the quarry feeds it.I thought you might use something similar.I misunderstood.
Our wildlife enjoys all the water.
They had similar problems in France in the heatwave of 2003. Good job they've "not yet discovered Air-Conditioning" as the joke goes!
And yes you often get lighter winds when demand for cooling is high. But does the sun go in?...
As usual, solar shows its strengths against the competition. Too bad the billions spent on coal & nukes aren't spent instead on putting PV on every available roof (which would also cut down on the power needed to cool those homes & businesses in the summer). Spend some of that $ on local energy storage facilities and you have a 24/7 solution.