Nuclear Loses Its Cool (Scientific American blog)

[jpak]

http://blog.sciam.com/index.php?title=nuclear_loses_its_cool&more=1&c=1&tb=1&pb=1

One of the greater energy ironies of our modern era is that some of the nuclear power plants we rely on to provide our electricity in times of great heat don't actually handle that heat all that well. The aging nukes that litter the U.S.--and others throughout the world--require vast quantities of water as part of their cooling apparatus. And that cooling water becomes unreliable in the summer heat, just when we need the reactors to be making as much electricity as possible.



The water just isn't as cool as it could be under sweltering conditions. One of Exelon's power plants in Illinois had to cut its power output at the beginning of the week because the water from the mighty Mississippi simply couldn't cool enough of the steam the nuke produced to efficiently shuttle water back into the core. The results of this can be seen at American Electric Power's Cook plant in Michigan where temperatures in the control room reached 120 degrees F. And there are plenty of other examples.

This is not just a U.S. problem, reactors in Europe also had to shut down for fear that they would dump too much hot water into their adjacent rivers. Such thermal bands of water are responsible for boiling thousands of fish and other aquatic creatures every year (witness this image of the hot water band stretched across the entire Hudson near the Indian Point reactor).

Of course, new reactor designs (and other cooling materials) can help with this flaw in nuclear technology and the shutdowns had little impact on power-users (so far). But it certainly would seem as if turning to nuclear power to combat climate change might run into a few difficulties, even leaving aside for the moment the ever present waste, proliferation and safety (witness Sweden) issues. Hot weather may increase in some of the places where we would like to build power plants and hot weather means hot water in the rivers those plants would likely rely on to cool themselves.

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[index555]

1. on waste ,safety and future power

It's not so much that I'm "rabidly" pro nuke , the currently existing nuke reactors clearly have several serious issues, please read:
Ref: Scientific American , Dec 2005 "smarter use of nuclear waste"
According to this article we can eliminate %98(!) of the nuclear waste by reprocessing and reusing it.
not only that but the final unusable waste would be of isotopes that would decay to background levels in a few hundred years, not tens or hundreds of thousands of years.(!!) in another 50 years we might even find a use for that.(?){speculation on my part only, nevertheless a few hundred years is far better than trying to create a "nuclear waste priesthood" or somesuch to keep people or whatever curious intelligent creature that may come after us from fooling with the waste repository]
This along with replacing our current nuclear plants with smaller , current "inherently self limiting" designs as opposed to the 30-40 year old designs we have now(which are not self-limiting)
For those who don't know, an "inherently self-limiting reactor" is designed so that there is no way for it to run out of control or melt down.
If it gets too hot , the reaction slows down, causing it to cool.
even in total, catastrophic loss of coolant , the reaction shuts down, the reason that the reactors are smaller is so that they can radiate sufficient excess heat to the outside to prevent anything from melting. they are designed in such a way that"more heat=slower reactions"
They are designed not to NEED any emergency backup system {that could possibly fail, as evidenced by the events in Sweden)
These "slow-down", and "shut-down" features are built in to the design , and do not rely on control rod position or any mechanical system (such as cooling pumps)which could fail, or be accidentally(or deliberately) be set or controlled improperly .
These designs now exist, however it has been the incredibly vocal opposition of the "no nukes" people that has prevented them from being built.

As far as other alternative power sources are concerned? WE NEED TO INVEST FAR MORE IN EVERY ONE OF THEM! our energy problem is not simple and there is no simple solution to it.
We also need to PROMOTE ENERGY CONSERVATION!
I read an article(I believe it was on MSN) about a group of architects who were designing "green" energy efficient buildings for the reconstruction or New Orleans, THIS IS GREAT! We can (if we have the determination) turn the tragedy into a triumph by rebuilding GREEN! think of the advantages of reducing the energy bills of the poor residents there by as much as %75.
not to mention the reduced energy consumption overall.

I reject the arguments of the extreme "no-nukes is good nukes" bunch , while I don't think nuclear is the whole solution,intelligently used it IS part of the solution.

[JohnWxy]

2. important post. Whenever I hear the subject of water usage brought up

I have to wonder if people realize how much water nuclear uses and that the warmed discharge can be an environmental challenge.

I didn't know however (and I suspect many others also don't know), about the warmer weather being more of a challenge to nuclear because the cooling water is warmer.

thanks for this post. It's good to be as fully informed as possible (kindof helps in making better decisions).

[JohnWxy]

3. LInk to article about Exelon plant shut down due to warm river water

SHUT-DOWNS DUE TO HEAT AND AN "UNUSUAL EVENT"

http://jsalera.wordpress.com/2006/08/

energy.buzzHome Mississippi River’s water temperature leads Exelon to reduce power output at Quad Cities, Illinois nukes plants
August 2nd, 2006

NEW YORK, Aug 1 (Reuters) - With a heat wave warming the Mississippi River water used for cooling at the nuclear power plant in Quad Cities, Illinois, Exelon Corp. has cut the power at the plant about 19 percent, a spokeswoman said on Tuesday.

The 867-megawatt Quad Cities reactors were producing about 700 megawatts of power each after the reduction. The plant uses river water to condense steam from the turbine before returning the condensed water back to the reactor, while the river water flows back to the river.

With temperatures exceeding 90 degrees in the area around the plant, the hot river water can harm fish and other aquatic life and does not cool the reactor water as efficiently.

Meteorologists forecast temperatures in the area around the plant would reach 93 degrees Fahrenheit, according to forecaster AccuWeather.

This week, nuclear operators have reduced power output at several reactors due to high water temperatures including Xcel Energy Inc.’s…Prairie Island 1 and 2, and Monticello units in Minnesota over the weekend, and Exelon’s Dresden 2 unit in Illinois on Monday.

The 1,734 MW Quad Cities station is in Cordova in Rock Island County, about 155 miles west of Chicago. There are two 867-MW units, 1 and 2, at the station. Each entered service in 1972.

***The NRC actually lists that both Quad cities reactors electricity generation has been cut closer to 55 percent.

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Nuclear power plants Update: Michigans Fermi 2 declared an “unusual event” Monday
August 2nd, 2006

Add Unit 2 at the Fermi nuclear power station in Monroe, Michigan to the shutdown list. It shutdown on July 29 due to the loss of off-site power and experienced an “unusual event” while trying to power up again. The unusual event has ended and the plant is producing at 10 percent capacity according to the NRC.

Southeatern Michigan was without two nuclear power reactors for at least one, maybe two days. DTE energy is running radio commercials in my area asking customers to curtail use of appliances. The commercial cites heat, humidity and high power demand for as reasons for curtailing power usage.

DTE was also calling business customers asking them to reduce power conumption.

NEW YORK, Aug 1 (Reuters) - A problem with a fire suppression system delayed the return to service of DTE Energy Co.’s 1,111-megawatt Unit 2 at the Fermi nuclear power station in Michigan until later Tuesday, a spokesman for the Detroit-based company said.

The unit was operating at 10 percent power early Tuesday but had not synchronized with the power gird.

The spokesman said the unit would likely return to service later today - probably this afternoon - following a shutdown on July 29 due to the loss of off-site power.

As operators were increasing the reactor power on Monday, the company had to declare an unusual event, the lowest of the NRC’s four emergency classifications, due to the discharge of carbon dioxide gas into the cable tray room after 1 p.m. EDT, according to an NRC report.

The gas is part of the plant’s fire suppression system. The company however found no signs of fire or smoke.

The unit was operating at 6 percent at the time of the event and was increasing power.

The carbon dioxide discharge however forced the company to evacuate the reactor and auxiliary buildings. The plant did not exit the unusual event until after 9 p.m. It was not clear from the NRC report when the company allowed employees back into the reactor and auxiliary buildings.

This is the event as descibed on the NRC wesite:

UNUSUAL EVENT DECLARED DUE TO CO2 DISCHARGE TO THE CABLE TRAY ROOM

“At 1326 on 7/31/06 there was a discharge of CO2 to the cable tray room. This is not a normally accessible room. Plant personnel verified no smoke, no fire. At 1340 the order was given to evacuate all personnel from the Reactor and Auxiliary Buildings as a precautionary measure. An Unusual Event was declared (HU3) at 1344 due to the affect on normal operation of the plant. The CO2 has been isolated, the buildings are being walked down and atmospheric testing is underway in the affected areas.”

The licensee notified the NRC Resident Inspector, Canada, State and County officials.

* * * UPDATE ON 07/31/06 AT 15:17 FROM B. WALLAND TO A. COSTA * * *

“At 1344 an Unusual Event was declared due to a toxic release into the Auxiliary Building (HU3). Release was due to a CO2 initiation, and has been isolated. Reactor building and Auxiliary building have been evacuated. Air sampling of the affected areas is underway.”

Notified R3 DO (O’Brien).

* * * UPDATE ON 07/31/06 AT21:44 FROM N. MAJOR TO M. RIPLEY * * *

“Walk downs for atmospheric conditions are complete and satisfactory for all areas of the Auxiliary Building. Normal access to Auxiliary building has been restored. This restores access to all affected areas.

“Unusual Event is terminated at 2133.”

Notified IRD (T. Blount), R3 DO (K. O’Brien), NRR EO (M. Tschiltz), DHS (Biasco) and FEMA (Kimbrell).

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SHUT-DOWNS DUE TO HEAT:

Reductions and shutdown of nuclear power plants sweep the U.S.
August 1st, 2006

Last week saw nuclear power plants across Europe reduce or shutdown their production due to high water temperatures in the rivers where they are located. The only way some plants stayed open is they were given permission to stay in operation regardless of water temperatures.

Today reductions or shutdowns of production in U.S. nuclear plants are in the news.

Four of the plants mentioned below that reduced production were in full production on Friday. There is no statement that any of the reductions were planned and no explanations for the power reductions.

Why? Were the unplanned reductions heat related?

The one plant that was completely shut down was due to high temperatures in the containment room, hot weather, hot lake temperatures and a partial blockage of the ventilation system.

As we saw in Europe nuclear power plants raise the water temperatures of the rivers they reside on. How does that square with the nuclear industries claim that nuke plants will be our salvation from global warming?

And if nuclear power plants can’t stay in operation on hot days without mass fish and wildlife kills in rivers, are they the green dreams we’re led to believe?



NEW YORK, July 31 (Reuters) - American Electric Power Co Inc. said on Monday it has shut its 1,016-megawatt Unit 1 at the Cook nuclear power station in Michigan on July 30 due to scorching weather.

A spokesman for the Columbus, Ohio-based company said the unit was shut down because the temperature in the containment room reached 120 degrees Fahrenheit (49 degrees Celsius), exceeding allowable levels.

The spokesman said the room temperatures - not the reactor temperature - exceeded limits due to the hot weather outside the plant, the hot lake temperatures and a partial blockage of the ventilation system.