Actually, Pu238 isn't used in "normal" nuclear power plants. That's the isotope apparently in short supply that NASA needs for its space missions. It just kind of sits and cooks generating heat. Pu238 is packed into canisters and used to generate electricity by heating thermocouple junctions. The process uses the natural decay of the Pu238. It's not a chain reaction.
In reactors used to generate electricity, it is a chain reaction that gets moderated by the reactor and the control rods. U235 will undergo both spontaneous fission as well as induced fission (what you need for a chain reaction). U235, U238, and Pu239 are used in nuclear reactors. As soon as you fire one up, though, all sorts of other elements/isotopes start being generated and there are lots of radioactive byproducts produced.
That's one reason why they can show you pictures of nuclear plant workers holding reactor fuel pellets -- they are not very radioactive. However, once the fuel rods have been in a reactor for a while, they get very radioactive and have to be stored in pools of water after removal to both cool them and to contain the radiation as the radioactive byproducts, frequently with short half lives, are very radioactive.
This is one reason that spent fuel rods from a reactor are at least a little safer from terrorists than fresh. They will kill anyone who goes near them because they are so radioactive.
After the short half life stuff dies off, the radiation levels drop, and the spent rods can be more easily reprocessed to remove useful fuel to make new.
Nope. You don't need breeders to make plutonium. It is a byproduct of fission products (i.e. neutrons) hitting other uranium atoms in the fuel rods. Breeders are just designed to do it. Regular reactors do it as well. Take a look at some of the weblinks in the posts.
Making that chain reaction run, but run slow, is why there are nuclear reactors. Those generally get a bit unwieldy to mount on the top of a rocket to send into space. Plus you gradually get a very radioactive reactor that needs lots of shielding to protect a NASA satellite from radiation.
As many others have noted, Pu238 in the thermoelectric generators is not the same as Pu239 in nuclear warheads. Pu238 is an alpha emitter which makes shielding pretty easy. Alpha particles are just helium nuclei and can be stopped by just about anything. Even though Pu238 is pretty radioactive due to the short (88 year) half life, the radiation is easily contained.
Thermoelectric generators just get really hot in the thermal sense and not so hot in the radioactive sense other than the alpha decay route that generates the heat.
Also, though a breeder may be more efficient at making them (I don't know), it isn't required. Plutonium was first made in the X-10 graphite reactor at Oak Ridge. All rectors that use uranium as fuel will produce plutonium. If you read the Wikipedia articles on breeder reactors, all light water reactors gradually transition from predominately burning their starting fuel to predominately burning the new isotopes that get bred into the fuel rods.
Not entirely true. You operate the reactors and process the fuel rods differently, and I would assume load the fuel rods differently, depending on the isotope you want to make.
If you read the Global Security link I added, you will see. If you want to make predominately Pu239, you go with short run cycles so you don't get buildup of other, more radioactive isotopes, that make handling the fuel rods more problematic. You also want to use more U238 in the rods.
I would guess (as I don't know) that based on the Global Security article, if you want to make Pu238, you would start with more U235 in the rods and maybe run longer between reprocessing cycles.
If you want to read an excellent discussion of reactor vs. weapons grade plutonium (though there isn't much information on Pu238 for thermoelectric generators) go here: http://www.globalsecurity.org/wmd/intro/pu-isotope.htm
Methods used to make the two isotopes (weapons grade Pu239 vs. thermoelectric generator Pu238) are quite different.
Pu239 is produced from U238 when it absorbs a neutron and decays to Pu239.
Pu238 is produced with U235 through a chain of neutron absorptions and decays.
U238 is the more common form of uranium and is not the kind used for uranium weapons. Relatively pure U235 is what is frequently called highly-enriched uranium (HEU) and is the kind used for weapons.
Hey all - there is a very important concept to this discussion that most don't seem to be aware of.
Pu239 is the isotope of plutonium that is used in weapons. It has a very long half life (~24,000 years) and works great in nuclear weapons since it releases neutrons when the nucleus breaks apart and those neutrons cause other nuclei to break apart as well in a massive chain reaction that releases huge amounts of energy. (Normal decay path is through alpha particle emission (helium nuclei))
Pu238 is the isotope used in thermoelectric energy generators. It has a relatively short half live of ~88 years. Because of the shorter half life, it is a lot more radioactive than Pu239. The nucleus spontaneously undergoes alpha decay and releases enough energy frequently enough that chunks of this isotope glow red from the heat.
The plutonium used in warheads cannot be used in thermoelectric generators and vice versa.
Agreed completely. The farther away, the longer the signals take to get to/from the remote destination. The Mars landers could only creep ahead because the operators here on earth couldn't risk just sending them blindly along. What allowed the Mars landers to cover so much ground was the many months they were there having operators move them around inch by inch and foot by foot.
The astronauts on the moon were able to scoot around like crazy on the rovers. Being there and operating something in real time would be a huge benefit to research of any kind. Instead of sending the command to have a camera pan around to decide where to go next, waiting the 20 minutes or so for it to get there, waiting another 20 or so minutes for the video feed to even start arriving, and you see the issue. A human could just look around and hit the gas pedal. Yeah - that rock over there looks interesting.
Dude - you don't send ashes. If we're going to send a dead person, send a corpse. At least it would be a galactic practical joke for whatever race found the skeletal remains. It would be a bit Robinson Caruso on Mars.
Hell, I'd send my dead body in a heartbeat. Talk about beating the heck out of burying me in some weed-eaten old graveyard that eventually gets moved to make room for a shopping center!
Accomplishing something means administering multiple compute clusters, writing documents, editing spreadsheets, building the occasional presentation (all in OpenOffice), reading and writing e-mail, researching things on the web, and even playing games.
There are plenty of "real" applications for Linux. If you had a clue what you were talking about you would know just how many real applications there are. But you don't.
Might I suggest the Vista to XP downgrade? It might make you a wee tad more pleasant.
My ass. The best guidance NASA ever had was when John F. Kennedy sent the United States to the moon.
This "guidance" is nothing more than the best idea a stupid chimp could come up with at the time to try to ride Kennedy's coattails.
As with just about anything Bush, going to the moon again is pretty stupid. What's the purpose? Hell, all we would need to do is just build a few new Saturn V's, a new LEM or two, and another couple of Lunar Rovers. We have all the plans and we know they work.
Wasting the time and money on doing something we did almost 40 years ago is typical for our diminutive presidenter.
Someone put him back on a Segway and hand him a pretzel.
It's amazing how people can have such strong feelings about an issue and have them be based on such utter nonsense.
Have you ever jump-started a car? Did you not notice how when you connect jumper cables to the vehicle with the dead battery, the running car has its engine get slogged down by the extra load? And does it not stand to reason that if you want to hold the engine at the same RPM (as an electric utility has to do to hold line frequency) you have to feed the engine more gas to do so?
If you draw more power out of a circuit, somewhere, more power has to be put in.
Peak load is why extra power plants need to be built. Sure, it is great to decrease that to prevent the extra emissions. But the loads at all times of the day and night should be reduced as well where possible.
Isn't this the same argument BushCo uses over and over to keep from revealing what they are really up to?
There is no logical reason why California cannot get this information other than it is to cover BushCo butts.
Go ahead, Bush apologists, and mod me down but you know the truth - Bush and his corporate interests are selling you out, selling your country out, and selling your futures out.
There is a show on one of the cable channels called "Gangland". One of their recent episodes discussed how the lowered requirements for "volunteers" entering the military has led to widespread infiltration by gangs. They showed lots of tagging over in Iraq and related it back to gangs in American cities. They also showed a German nightclub packed with "soldiers" bouncing up and down and flashing gang signs.
They were talking with military people who were outlining what this is doing to our military, to the cities where these people are deployed and the attitudes towards the USA because of the new levels of crime, and how this is putting our National security at risk as well as our relationships with the countries that allow us to have bases there.
All thanks to a war that never had to happen, was pushed for by a corrupt president and vice president, and was cheered by the republicans.
Admit it or not, but the USA is becoming a worldwide pariah. And it can virtually all be laid at the feet of little "dubya".
At least NASA has the intelligence and a plan to reverse the idiocy that George threw at them in his effort to paint himself like JFK.
Asteroids are a danger. The odds of one hitting the earth are slim, but if one did, it could end most life on the planet. I'm glad NASA is able to stand up to the little dictator.
It's pretty simple, really. The magnetic charge port. Apple can offer a battery pack that recharges the Air's battery, extends operating time, etc. It would be just like the AC power supply except it would run off of DC. It could still run with typical laptop batteries (Li-ion and such) for high power densities but it also wouldn't need to be some oddball configuration that drives up manufacturing costs. It could be a basic brick more or less.
The Air has a power port. Getting extra run time when on aircraft without power plugs, etc, is nothing more than supplying power to the power port.
Efficiencies also depend on how Apple configured the power port. With just a little forethought, they could have made it where a portable power pack (i.e. auxiliary battery) just runs the Air itself and doesn't recharge the onboard battery. That would be more efficient than accepting charging efficiency losses and the only down side would be having to carry an assembly with cord instead of just an extra battery. A fairly acceptable compromise to trying to make removable batteries in such a tight form factor.
Actually, the original post was a clip from a SANS NewsBites email. While it did come out on Friday, the main announcement was probably sometime during the week.
You can still have flexibility. Just have the callback call a number you can call-forward. Then if you are in another location, just set call-forwarding to the new number before calling in.
As to SSL, two-way certificates, etc, you just use a gateway, maybe with VPN, etc, and let the gateway handle the authentication/encryption duties and once you are in, you can talk to the simple embedded stuff.
My bet is that,probably like so many installations that get hit with penetrations and then screwed with, the systems were not adequately protected, probably had other services running they didn't need (i.e. someone did a full install instead of taking the time to custom-configure), they weren't patched, etc. So many people are too lazy, busy, overworked, etc, to follow even the most basic security precautions until they get bit in the arse.
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Actually, Pu238 isn't used in "normal" nuclear power plants. That's the isotope apparently in short supply that NASA needs for its space missions. It just kind of sits and cooks generating heat. Pu238 is packed into canisters and used to generate electricity by heating thermocouple junctions. The process uses the natural decay of the Pu238. It's not a chain reaction.
In reactors used to generate electricity, it is a chain reaction that gets moderated by the reactor and the control rods. U235 will undergo both spontaneous fission as well as induced fission (what you need for a chain reaction). U235, U238, and Pu239 are used in nuclear reactors. As soon as you fire one up, though, all sorts of other elements/isotopes start being generated and there are lots of radioactive byproducts produced.
That's one reason why they can show you pictures of nuclear plant workers holding reactor fuel pellets -- they are not very radioactive. However, once the fuel rods have been in a reactor for a while, they get very radioactive and have to be stored in pools of water after removal to both cool them and to contain the radiation as the radioactive byproducts, frequently with short half lives, are very radioactive.
This is one reason that spent fuel rods from a reactor are at least a little safer from terrorists than fresh. They will kill anyone who goes near them because they are so radioactive.
After the short half life stuff dies off, the radiation levels drop, and the spent rods can be more easily reprocessed to remove useful fuel to make new.
Nope. You don't need breeders to make plutonium. It is a byproduct of fission products (i.e. neutrons) hitting other uranium atoms in the fuel rods. Breeders are just designed to do it. Regular reactors do it as well. Take a look at some of the weblinks in the posts.
Making that chain reaction run, but run slow, is why there are nuclear reactors. Those generally get a bit unwieldy to mount on the top of a rocket to send into space. Plus you gradually get a very radioactive reactor that needs lots of shielding to protect a NASA satellite from radiation.
As many others have noted, Pu238 in the thermoelectric generators is not the same as Pu239 in nuclear warheads. Pu238 is an alpha emitter which makes shielding pretty easy. Alpha particles are just helium nuclei and can be stopped by just about anything. Even though Pu238 is pretty radioactive due to the short (88 year) half life, the radiation is easily contained.
Thermoelectric generators just get really hot in the thermal sense and not so hot in the radioactive sense other than the alpha decay route that generates the heat.
Also, though a breeder may be more efficient at making them (I don't know), it isn't required. Plutonium was first made in the X-10 graphite reactor at Oak Ridge. All rectors that use uranium as fuel will produce plutonium. If you read the Wikipedia articles on breeder reactors, all light water reactors gradually transition from predominately burning their starting fuel to predominately burning the new isotopes that get bred into the fuel rods.
http://en.wikipedia.org/wiki/Breeder_reactor
Not entirely true. You operate the reactors and process the fuel rods differently, and I would assume load the fuel rods differently, depending on the isotope you want to make.
If you read the Global Security link I added, you will see. If you want to make predominately Pu239, you go with short run cycles so you don't get buildup of other, more radioactive isotopes, that make handling the fuel rods more problematic. You also want to use more U238 in the rods.
I would guess (as I don't know) that based on the Global Security article, if you want to make Pu238, you would start with more U235 in the rods and maybe run longer between reprocessing cycles.
It's interesting stuff.
If you want to read an excellent discussion of reactor vs. weapons grade plutonium (though there isn't much information on Pu238 for thermoelectric generators) go here: http://www.globalsecurity.org/wmd/intro/pu-isotope.htm
Methods used to make the two isotopes (weapons grade Pu239 vs. thermoelectric generator Pu238) are quite different.
Pu239 is produced from U238 when it absorbs a neutron and decays to Pu239.
Pu238 is produced with U235 through a chain of neutron absorptions and decays.
U238 is the more common form of uranium and is not the kind used for uranium weapons. Relatively pure U235 is what is frequently called highly-enriched uranium (HEU) and is the kind used for weapons.
Hey all - there is a very important concept to this discussion that most don't seem to be aware of.
Pu239 is the isotope of plutonium that is used in weapons. It has a very long half life (~24,000 years) and works great in nuclear weapons since it releases neutrons when the nucleus breaks apart and those neutrons cause other nuclei to break apart as well in a massive chain reaction that releases huge amounts of energy. (Normal decay path is through alpha particle emission (helium nuclei))
Pu238 is the isotope used in thermoelectric energy generators. It has a relatively short half live of ~88 years. Because of the shorter half life, it is a lot more radioactive than Pu239. The nucleus spontaneously undergoes alpha decay and releases enough energy frequently enough that chunks of this isotope glow red from the heat.
The plutonium used in warheads cannot be used in thermoelectric generators and vice versa.
Agreed completely. The farther away, the longer the signals take to get to/from the remote destination. The Mars landers could only creep ahead because the operators here on earth couldn't risk just sending them blindly along. What allowed the Mars landers to cover so much ground was the many months they were there having operators move them around inch by inch and foot by foot.
The astronauts on the moon were able to scoot around like crazy on the rovers. Being there and operating something in real time would be a huge benefit to research of any kind. Instead of sending the command to have a camera pan around to decide where to go next, waiting the 20 minutes or so for it to get there, waiting another 20 or so minutes for the video feed to even start arriving, and you see the issue. A human could just look around and hit the gas pedal. Yeah - that rock over there looks interesting.
Dude - you don't send ashes. If we're going to send a dead person, send a corpse. At least it would be a galactic practical joke for whatever race found the skeletal remains. It would be a bit Robinson Caruso on Mars.
Hell, I'd send my dead body in a heartbeat. Talk about beating the heck out of burying me in some weed-eaten old graveyard that eventually gets moved to make room for a shopping center!
Accomplishing something means administering multiple compute clusters, writing documents, editing spreadsheets, building the occasional presentation (all in OpenOffice), reading and writing e-mail, researching things on the web, and even playing games.
There are plenty of "real" applications for Linux. If you had a clue what you were talking about you would know just how many real applications there are. But you don't.
Might I suggest the Vista to XP downgrade? It might make you a wee tad more pleasant.
Does Bill kiss you after you blow him?
Because what I want to do today is get my work done.
My ass. The best guidance NASA ever had was when John F. Kennedy sent the United States to the moon.
This "guidance" is nothing more than the best idea a stupid chimp could come up with at the time to try to ride Kennedy's coattails.
As with just about anything Bush, going to the moon again is pretty stupid. What's the purpose? Hell, all we would need to do is just build a few new Saturn V's, a new LEM or two, and another couple of Lunar Rovers. We have all the plans and we know they work.
Wasting the time and money on doing something we did almost 40 years ago is typical for our diminutive presidenter.
Someone put him back on a Segway and hand him a pretzel.
DOE = The US Department of Energy
It's amazing how people can have such strong feelings about an issue and have them be based on such utter nonsense.
Have you ever jump-started a car? Did you not notice how when you connect jumper cables to the vehicle with the dead battery, the running car has its engine get slogged down by the extra load? And does it not stand to reason that if you want to hold the engine at the same RPM (as an electric utility has to do to hold line frequency) you have to feed the engine more gas to do so?
If you draw more power out of a circuit, somewhere, more power has to be put in.
Peak load is why extra power plants need to be built. Sure, it is great to decrease that to prevent the extra emissions. But the loads at all times of the day and night should be reduced as well where possible.
I agree - looking after the planet is not altruism. It's common sense.
Looking after the planet is like not peeing in your bed, not crapping in your food, and not setting your own home on fire.
But some idiots don't understand that.
Isn't this the same argument BushCo uses over and over to keep from revealing what they are really up to?
There is no logical reason why California cannot get this information other than it is to cover BushCo butts.
Go ahead, Bush apologists, and mod me down but you know the truth - Bush and his corporate interests are selling you out, selling your country out, and selling your futures out.
I'm sorry you're not too.
Every Wake on LAN I've seen is just a jumper from the network card or a BIOS setting for the built-in ethernet ports.
There is a show on one of the cable channels called "Gangland". One of their recent episodes discussed how the lowered requirements for "volunteers" entering the military has led to widespread infiltration by gangs. They showed lots of tagging over in Iraq and related it back to gangs in American cities. They also showed a German nightclub packed with "soldiers" bouncing up and down and flashing gang signs.
They were talking with military people who were outlining what this is doing to our military, to the cities where these people are deployed and the attitudes towards the USA because of the new levels of crime, and how this is putting our National security at risk as well as our relationships with the countries that allow us to have bases there.
All thanks to a war that never had to happen, was pushed for by a corrupt president and vice president, and was cheered by the republicans.
Admit it or not, but the USA is becoming a worldwide pariah. And it can virtually all be laid at the feet of little "dubya".
***IS***. George Bush IS an unpopular president. We still have another year of the little Alfred E. Newman lookalike bastard.
At least NASA has the intelligence and a plan to reverse the idiocy that George threw at them in his effort to paint himself like JFK.
Asteroids are a danger. The odds of one hitting the earth are slim, but if one did, it could end most life on the planet. I'm glad NASA is able to stand up to the little dictator.
It's pretty simple, really. The magnetic charge port. Apple can offer a battery pack that recharges the Air's battery, extends operating time, etc. It would be just like the AC power supply except it would run off of DC. It could still run with typical laptop batteries (Li-ion and such) for high power densities but it also wouldn't need to be some oddball configuration that drives up manufacturing costs. It could be a basic brick more or less.
The Air has a power port. Getting extra run time when on aircraft without power plugs, etc, is nothing more than supplying power to the power port.
Efficiencies also depend on how Apple configured the power port. With just a little forethought, they could have made it where a portable power pack (i.e. auxiliary battery) just runs the Air itself and doesn't recharge the onboard battery. That would be more efficient than accepting charging efficiency losses and the only down side would be having to carry an assembly with cord instead of just an extra battery. A fairly acceptable compromise to trying to make removable batteries in such a tight form factor.
Actually, the original post was a clip from a SANS NewsBites email. While it did come out on Friday, the main announcement was probably sometime during the week.
You can still have flexibility. Just have the callback call a number you can call-forward. Then if you are in another location, just set call-forwarding to the new number before calling in.
As to SSL, two-way certificates, etc, you just use a gateway, maybe with VPN, etc, and let the gateway handle the authentication/encryption duties and once you are in, you can talk to the simple embedded stuff.
My bet is that,probably like so many installations that get hit with penetrations and then screwed with, the systems were not adequately protected, probably had other services running they didn't need (i.e. someone did a full install instead of taking the time to custom-configure), they weren't patched, etc. So many people are too lazy, busy, overworked, etc, to follow even the most basic security precautions until they get bit in the arse.