Maybe a better way to say what you meant would be:
"A BWR is designed to contain more excess reactivity than an equivalent PWR, because it must compensate for the negative void coefficient. This excess reactivity makes a BWR less susceptible to xenon precluded startups."
You could achieve the same thing in a PWR by simply loading more fuel or using more enriched fuel. The downside is that you require more control rods to compensate for the excess reactivity.
It's really amazing that these basic principals of thermodynamics were all figured out in the early 1800s, but almost 200 years later people still don't get it.
BWRs have the advantage of NOT being Xenon-precluded because the Void coefficient of reactivity is non-existent.
What you are saying might be true for a specific reactor design, but zero void coefficient is by no means inherent to all BWRs.Not to mention that void coefficient has nothing whatsoever to do with xenon-precluded startups
The temperature inside your condenser is always higher than temperature of the water you send back into the river.
The temperature of your condenser is directly related to the pressure of saturated steam/condensate mixture. Higher temperatures correlate to higher pressures in the condenser.
Condensers are only designed to withstand a certain amount of pressure
The work your turbine can produce is directly proportional to the difference in pressure between the steam supply and the condenser.
You are just playing word game with the definition of "efficient". There is a fundamental limit of how much work can be extracted by heat flow between two temperatures.
I would expect a country with a colder climate to be able to extract more work out of a nuclear reactor. Those super-efficient reactors won't do so well with a 90 Fahrenheit cooling medium
A static body of water will have the same year around average temperature as the air, but the instantaneous temperature will lag the air temperature due to the heat capacity of the water.
Not true; besides the effect of snow melt you mentioned there is the effect of evaporation which keeps the river cooler that the ambient air on average.
Almost always the river water is cooler than the air temperature and has a much larger specific heat capacity. If the plant was modified to run completely on air cooling, it would be far less efficient 99.9% of the time,
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?"
Let's say you are a hiring people to perform some job, fly a plane, perform neurosurgery, operate a nuclear reactor, etc.
Suppose some applicant described his belief that the earth is actually flat during the interview. Would you really say, "Who am I to shove my beliefs down your throat? Your're hired!"
They describe it as traveling at "supersonic" speeds when they should know there is no sound in the vacuum of space.
Actually, there is interstellar dust that can propagate waves. Any medium that can propagate waves has a "speed of sound", but the sounds that travel through that dust are beyond a human's hearing range.
I like the idea of more stuff available in google maps / google earth. Very few things annoy more now than a business website that uses some other mapping program.
The first time I ever used the google maps website where you could navigate by click-and-drag instead of CGI, I immediataly added
127.0.1.1 www.mapquest.com to/etc/hosts *
*not really
Re:Dude, that article sucked.
on
Hardening Linux
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· Score: 1
It seems like you could do just as well with a shared library.
Except this isn't an example of "unbridled market capitalism". The original copper network was a private/public compromise built on private property seized by the government with its power of immanent domain.
The federal government allowed monopoly control of the copper by one company, as long as it agreed to follow certain rules that a normal company would not need to. That is why multiple phone companies were allowed to compete on the same copper.
Now we have the case where companies are not fulfilling their part of the bargain and the government isn't enforcing it any more.
Re:Dude, that article sucked.
on
Hardening Linux
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· Score: 1
Do people really still use xinetd? I understand how on the 486 with 8 MB of ram you couldn't afford to keep all you services running all the time, but now?
In my mind this is just like the mbox vs. maildir arguement. It took about 10 years after MFM drives stopped being used until everyone realized that mbox wasn't faster anymore.
Slashdot Mirror
Maybe a better way to say what you meant would be:
"A BWR is designed to contain more excess reactivity than an equivalent PWR, because it must compensate for the negative void coefficient. This excess reactivity makes a BWR less susceptible to xenon precluded startups."
You could achieve the same thing in a PWR by simply loading more fuel or using more enriched fuel. The downside is that you require more control rods to compensate for the excess reactivity.
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.
It's really amazing that these basic principals of thermodynamics were all figured out in the early 1800s, but almost 200 years later people still don't get it.
The temperature of your condenser is directly related to the pressure of saturated steam/condensate mixture. Higher temperatures correlate to higher pressures in the condenser.
You are just playing word game with the definition of "efficient". There is a fundamental limit of how much work can be extracted by heat flow between two temperatures.
I would expect a country with a colder climate to be able to extract more work out of a nuclear reactor. Those super-efficient reactors won't do so well with a 90 Fahrenheit cooling medium
Not true; besides the effect of snow melt you mentioned there is the effect of evaporation which keeps the river cooler that the ambient air on average.
Almost always the river water is cooler than the air temperature and has a much larger specific heat capacity. If the plant was modified to run completely on air cooling, it would be far less efficient 99.9% of the time,
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?"
Physics: It's not just a good idea, it's the law.
Let's say you are a hiring people to perform some job, fly a plane, perform neurosurgery, operate a nuclear reactor, etc.
Suppose some applicant described his belief that the earth is actually flat during the interview. Would you really say, "Who am I to shove my beliefs down your throat? Your're hired!"
http://en.wikipedia.org/wiki/Heliopause#Outer_stru cture
Someone already did it
I like the idea of more stuff available in google maps / google earth. Very few things annoy more now than a business website that uses some other mapping program.
/etc/hosts *
The first time I ever used the google maps website where you could navigate by click-and-drag instead of CGI, I immediataly added
127.0.1.1 www.mapquest.com
to
*not really
It seems like you could do just as well with a shared library.
Except this isn't an example of "unbridled market capitalism". The original copper network was a private/public compromise built on private property seized by the government with its power of immanent domain.
The federal government allowed monopoly control of the copper by one company, as long as it agreed to follow certain rules that a normal company would not need to. That is why multiple phone companies were allowed to compete on the same copper.
Now we have the case where companies are not fulfilling their part of the bargain and the government isn't enforcing it any more.
Do people really still use xinetd? I understand how on the 486 with 8 MB of ram you couldn't afford to keep all you services running all the time, but now?
In my mind this is just like the mbox vs. maildir arguement. It took about 10 years after MFM drives stopped being used until everyone realized that mbox wasn't faster anymore.
Houston, we have a unit problem
True, but nothing stops them from using the same voice actor
I hope not. At least not the Fenix character's...