I've stayed at CitiezenM in Times Square. Damn nice hotel for the price.
If I'm visiting New York City I'm not there to hang out in the hotel room. All I need is a _clean_ room, soft king bed (I'm tall and my wife likes her space;-) and a _clean_ bathroom. CitizenM covers this perfectly.
However, I would personally never stay somewhere with a shared bathroom! That's a bit _too_ "European" for my tastes:-)
Breeders are not a weapons proliferation problem... in fact, breeders are often cited as being "proliferation resistant"... especially thorium breeders.
But what does that have to do with what we were talking about?
Illegal where? No design is "illegal" in the US... provided you fully qualify its safety to the satisfaction of the NRC.
Many of those types of reactors have been built and are operating in other parts of the world.
So far, in the US, there hasn't been enough economic insentive to drive the adoption of anything beyond light-water reactors... but that doesn't mean the other designs are "illegal".
If you're going to continue to post FUD about nuclear power... you should at least educate yourself. Go take a "101" style coarse in nuclear engineering at your nearest university...
In the meantime, here are some reactor designs that don't use water for cooling or moderation:
You do realize that nuclear reactors are only refueled every _year and a half_... right? I would call that WAY more "efficient" than the line of coal cars that needs to flow through a coal plant every day....
Thermodynamic efficiency means nothing when your fuel source has _millions_ of times more energy in it...
I'm not sure what side you're arguing here. There are two main types of Light-Water Reactors (LWRs): Pressurized Water Reactors (PWRs) which run at ~15 MPa and keep liquid water in the core and Boiling Water Reactors (BWRs) that run at a lower pressure (~7 MPa) and boil the water straight to steam in the reactor core.
In the US about 2/3 of our reactors are PWRs and about 1/3 BWRs.
Both types of reactors have engineering challenges... but the efficiency really comes down to the laws of thermodynamics.
That's exactly what's done in Boiling Water Reactors (BWRs): https://en.wikipedia.org/wiki/... . They make up about 1/3 of the nuclear power plants in the U.S. in fact.
They have their own plusses and minuses vs Pressurized Water Reactors. Chiefly: they don't need complex heat exchangers between the primary and secondary systems that a PWR has... because there is only one system! But: they have a lower power density... mainly due to running at lower pressures and lower water densities (which actually reduces the fission reaction through a loss of moderation).
In a pressurized water reactor there are typically 3 loops: primary, secondary and "feedwater".
Both the primary and secondary loops are closed... but can hardly be considered "radioactive". The water in the primary system will develop a small (very small) amount of tritium that will build up. Tritrium does have a medium length half-life (about 12 years) so you wouldn't want to drink a bunch of it... but it also won't be radioactive for long. However, the amount in the primary system is really small.
Other reactor types (like CANDU) that use heavy water (deuterium) are much more likely to develop tritium... but even then it is a tiny amount (a few kilograms a year in thousands of tons of water).
The primary and secondary are really closed because they're at high pressure and have carefully controlled chemistry (to keep down corrosion and, in the case of the primary system, to help control the nuclear reaction using boron (dissolved boric acid).
The feedwater (which is what comes from rivers/lakes/oceans typically) is simply there to condense the steam generated in the secondary system back into water after it flows through the turbine.
Even if you "scrape the epoxy off the memory chips and read the data out" all you're going to be reading out is encrypted bits. Yes, by reading out those encrypted bits it could be possible to then try to brute-force attack the encryption... but you make it sound like they could just read the data directly... which is not true.
Unless you want to write your own OS and create your own hardware you have no choice. Yes, you can use an Open Source OS so at least in theory it's possible to verify the code on your own... but there is so much firmware embedded in each and every chip you get there is no way you're going to be able to verify the phone from top to bottom.
In the end, you have to go by reputation and track records and make an informed decision. In my mind Apple has always been firmly on the side of privacy compared to many other companies.
So I guess the question back to you is: why _not_ trust them? Or, better: who do you trust more?
No: What's been stated is that if Apple is in physical possession of the phone they can put the phone in a special mode and forcibly update portions of the operating system.
This is not an issue with the normal system that's built in that people use to update their operating system.
However, I do expect Apple to close even this final loophole in the next version of iOS. Instead of encrypting just the user's data on the phone... EVERYTHING will be encrypted... including the OS.
There is no vulnerability here. There are no such thing as "automatic updates" of iOS. There are "auto-downloaded" updates... but you ALWAYS have to install them manually... and to do so you need to unlock the device AND put in your iCloud username and password.
I use Uber a few times a week... and I am starting to see more and more senior drivers. When talking to them about why they do Uber they always remark that it's a great way to meet people and have interesting conversations. One guy the other day actually said "I can either sit at McDonalds and listen to women chatter about nothing or I can drive people around and have good conversations" (his words, not mine!)
I typically find the senior citizen drivers to be quite nice to ride with... although they are definitely slower;-)
You are correct that "used" fuel is mostly made up of Uranium that is an energy resource.
The issue is that it's co-mingled with a bunch of nasty stuff. Stuff that generates heat and radioactivity while it decays (which makes handling the used fuel difficult and expensive for reprocessing) and stuff that is a neutron "poison" (meaning it soaks up neutrons, lowering the neutron economy of the fuel).
We have the technology to separate out the good stuff from the bad (France does it in fact) but it is very expensive. At current Uranium prices it's uneconomical - France does it because it believes "it's the right thing to do" (TM). However, in the future we could come up with new reprocessing technology that makes it cheaper (many scientists are working on that) _or_ the price of Uranium could go up to where reprocessing would be economical (although, it may just price nuclear out of the market completely).
One interesting thing: The (failed) Yucca Mountain fuel repository was explicitly designed to allow for retrieval of used fuel. Fuel was to sit on moveable platforms on "train tracks" that would allow both simple placement _and_ retrieval at a later date. This was a "just in case" type deal... at the advent of simplified reprocessing Yucca Mountain would have just been "hanging out" with tons of good stuff that's easily retrievable. All of the other long-term geological repository solutions (like salt-mines and bore-holes) don't have this nice property;-)
"Uranium reactors, regardless of 'Gen' use fuel that is enriched to about 6%. That means 6% fissionable Uranium, 94% non fissionable."
Two words to learn:
Fissile: Can be easily fissioned with "thermal" neutrons (typically, neutrons around 0.025 eV... also known as "slow" or "low energy" neutrons).
Fissionable: Can fission. Period.
U-235 is "fissile" while U-238 is "fissionable".
The "94%" you talk about (BTW: in the U.S. the limit for enrichment is 5%, most fuel is enriched to 4.8% or so to leave a little bit of headroom) is U-238 and is definitely "fissionable". Several types of reactors have been built over the years that can burn U-238 directly including fast reactors and others that are "high neutron economy" reactors like CANDU, Magnox and AGR which can burn Uranium with very little or no added enrichment.
Fast reactors can work with U-238 because above 1 MeV the fission cross-section for U-238 is large enough (and the capture cross-section simultaneously low enough) that U-238 can sustain the nuclear reaction. This works because neutrons are born with energies ranging from keV up to 20 MeV (although, the average is around 2 MeV).
CANDU can burn natural uranium (Which is only about 0.7% U-235) because of good neutron economy. It utilizes "heavy water" (deuterium/H-2) to slow down the neutrons. H-2 has an almost negligible capture cross-section meaning that nearly all of the neutrons that are born make it down to "thermal" energies where it will fission with U-235. However, since it is still relying on the small amount of U-235 the fuel is depleted fairly quickly, requiring constant refueling (not joking, it is literally refueled continuously). It would certainly be able to burn "spent" light-water reactor fuel though... that "measly" less than 1% (not 3% like you state) enriched stuff would actually be more than the amount of U-235 that typically goes into a CANDU reactor! Of course, some of the built up fission products are neutron poisons, so that would reduce the neutron economy a bit... but it would still be able to maintain a critical reaction.
However, this is not done because it's just not economically feasible. Getting the old fuel from LWRs and shipping it somewhere to be disassembled (which has to be done carefully because when it comes out of the reactor it stays hot (both thermally and radioactivity wise) for quite a while) and put into fuel forms that would work in a CANDU reactor would cost way more than the effort is worth.
It is interesting that you simultaneously insult someone else, screw up a bunch of facts AND manage to make a (terrible) misogynistic joke all in the same post. That certainly undermines your credibility in my eyes...
"But there is no way that you take spend fuel from one reactor and put it into another one and continue burning it there."
That's not exactly true. Just the U-238 that's left in "used" fuel is good enough to sustain a critical reaction in a fast reactor or possibly even a thermal reactor that can utilize natural uranium like CANDU. However, there are many issues that keep this from being a reality (mostly economics).
(Note: I'm not a gun owner, so I'm just speculating)
I think one issue is a general "loss of control".
Guns are about controlling your immediate environment. Being able to respond (with the most basic of responses: physical harm) to threats to yourself and your family.
Anything that threatens to weaken that sense of control is going to have an uphill battle.
What is the end game on "smart guns"? Right now, it's just being used to make sure that the owner is the one firing the gun. In the future? Could it be used to remotely disable the gun?
For instance, many people are pushing for cars to feature a remote "kill switch"... where the police can remotely disable any car just by sending a wireless message to it. Could the same thing be coming to guns?
If smart guns take hold... could you imagine legislation coming down that requires smart guns to be disabled on demand by the police/military? This sounds "great": police roll in to a hostage situation and disable the guns of the assailants and then storm in. However, this may also be a Constitutional violation: is it a restriction on our right to bear arms? Does it give the government the exact authority (to oppress the populace without their ability to stand up to the government with force) the Constitution was trying to protect against?
Like I say: I'm not a gun owner... but that doesn't mean that I can't understand why gun owners would be against this. It's simply about control. Guns don't need to be "smart" to work... adding anything like this is opening the way toward more governmental control that possibly infringes our rights.
How do you get listed? My software project isn't listed. We have a few hundred users and we're nearing about 1000 citations. It's an open source project on GitHub.
You don't have to mess with your license at all. Scientists are good at citing things if you give them something to cite.
We try to publish a few papers yearly about new aspects of our software... and the scientists that use those pieces of the software naturally cite this papers without issue. We post our citations on our website and many people also email the mailing list to ask for the appropriate thing to cite when they're publishing findings based on our software.
However, Clang is significantly faster for our application. I would do some timings for you right now... but it takes too damn long to compile the entire stack with GCC;-) Last time I checked it was on the order of 25% faster. Over a whole day of compiling that can make a big difference.
The fact that, years later, _WE_ are still arguing about this proves that the case has merit.
If WE can't come to a consensus about this... then how is Joe Scmoe supposed to figure it out?
The fact is: this was _misleading_ advertising. They could have easily come up with another name for it (like Intel did with Hyperthreads)... instead they consciously chose to call the extra ALUs _cores_... which does have a meaning to the typical consumer. They did this, on purpose, to muddy the waters... and they REALLY did.
Does that mean that people shouldn't be more careful about what they buy? Sure. But that doesn't absolve AMD from putting out misleading advertising.
Slashdot Mirror
I've stayed at CitiezenM in Times Square. Damn nice hotel for the price.
If I'm visiting New York City I'm not there to hang out in the hotel room. All I need is a _clean_ room, soft king bed (I'm tall and my wife likes her space ;-) and a _clean_ bathroom. CitizenM covers this perfectly.
However, I would personally never stay somewhere with a shared bathroom! That's a bit _too_ "European" for my tastes :-)
Breeders are not a weapons proliferation problem... in fact, breeders are often cited as being "proliferation resistant"... especially thorium breeders.
But what does that have to do with what we were talking about?
Illegal where? No design is "illegal" in the US... provided you fully qualify its safety to the satisfaction of the NRC.
Many of those types of reactors have been built and are operating in other parts of the world.
So far, in the US, there hasn't been enough economic insentive to drive the adoption of anything beyond light-water reactors... but that doesn't mean the other designs are "illegal".
If you're going to continue to post FUD about nuclear power... you should at least educate yourself. Go take a "101" style coarse in nuclear engineering at your nearest university...
In the meantime, here are some reactor designs that don't use water for cooling or moderation:
Lead Cooled Fast Reactor: https://en.wikipedia.org/wiki/...
Gas Cooled Fast Reactor: https://en.wikipedia.org/wiki/...
Sodium Cooled Fast Reactor: https://en.wikipedia.org/wiki/...
Advanced Gas-cooled Reactor: https://en.wikipedia.org/wiki/...
Pebble-bed reactors: https://en.wikipedia.org/wiki/...
Inefficient? In what sense? Thermodynamically?
You do realize that nuclear reactors are only refueled every _year and a half_... right? I would call that WAY more "efficient" than the line of coal cars that needs to flow through a coal plant every day....
Thermodynamic efficiency means nothing when your fuel source has _millions_ of times more energy in it...
I'm not sure what side you're arguing here. There are two main types of Light-Water Reactors (LWRs): Pressurized Water Reactors (PWRs) which run at ~15 MPa and keep liquid water in the core and Boiling Water Reactors (BWRs) that run at a lower pressure (~7 MPa) and boil the water straight to steam in the reactor core.
In the US about 2/3 of our reactors are PWRs and about 1/3 BWRs.
Both types of reactors have engineering challenges... but the efficiency really comes down to the laws of thermodynamics.
That's exactly what's done in Boiling Water Reactors (BWRs): https://en.wikipedia.org/wiki/... . They make up about 1/3 of the nuclear power plants in the U.S. in fact.
They have their own plusses and minuses vs Pressurized Water Reactors. Chiefly: they don't need complex heat exchangers between the primary and secondary systems that a PWR has... because there is only one system! But: they have a lower power density... mainly due to running at lower pressures and lower water densities (which actually reduces the fission reaction through a loss of moderation).
Just a bit of clarification:
In a pressurized water reactor there are typically 3 loops: primary, secondary and "feedwater".
Both the primary and secondary loops are closed... but can hardly be considered "radioactive". The water in the primary system will develop a small (very small) amount of tritium that will build up. Tritrium does have a medium length half-life (about 12 years) so you wouldn't want to drink a bunch of it... but it also won't be radioactive for long. However, the amount in the primary system is really small.
Other reactor types (like CANDU) that use heavy water (deuterium) are much more likely to develop tritium... but even then it is a tiny amount (a few kilograms a year in thousands of tons of water).
The primary and secondary are really closed because they're at high pressure and have carefully controlled chemistry (to keep down corrosion and, in the case of the primary system, to help control the nuclear reaction using boron (dissolved boric acid).
The feedwater (which is what comes from rivers/lakes/oceans typically) is simply there to condense the steam generated in the secondary system back into water after it flows through the turbine.
Even if you "scrape the epoxy off the memory chips and read the data out" all you're going to be reading out is encrypted bits. Yes, by reading out those encrypted bits it could be possible to then try to brute-force attack the encryption... but you make it sound like they could just read the data directly... which is not true.
You have to trust someone.
Unless you want to write your own OS and create your own hardware you have no choice. Yes, you can use an Open Source OS so at least in theory it's possible to verify the code on your own... but there is so much firmware embedded in each and every chip you get there is no way you're going to be able to verify the phone from top to bottom.
In the end, you have to go by reputation and track records and make an informed decision. In my mind Apple has always been firmly on the side of privacy compared to many other companies.
So I guess the question back to you is: why _not_ trust them? Or, better: who do you trust more?
No: What's been stated is that if Apple is in physical possession of the phone they can put the phone in a special mode and forcibly update portions of the operating system.
This is not an issue with the normal system that's built in that people use to update their operating system.
However, I do expect Apple to close even this final loophole in the next version of iOS. Instead of encrypting just the user's data on the phone... EVERYTHING will be encrypted... including the OS.
There is no vulnerability here. There are no such thing as "automatic updates" of iOS. There are "auto-downloaded" updates... but you ALWAYS have to install them manually... and to do so you need to unlock the device AND put in your iCloud username and password.
There is NO backdoor here.
Glad someone put down what I was thinking.
"Not going" is simply not a choice for people who have dreamt and worked their whole lives to be in the Olympics.
All of the blame here is on the IOC. Sochi should have never happened... and neither should Brazil.
Actually: yes.
I use Uber a few times a week... and I am starting to see more and more senior drivers. When talking to them about why they do Uber they always remark that it's a great way to meet people and have interesting conversations. One guy the other day actually said "I can either sit at McDonalds and listen to women chatter about nothing or I can drive people around and have good conversations" (his words, not mine!)
I typically find the senior citizen drivers to be quite nice to ride with... although they are definitely slower ;-)
You are correct that "used" fuel is mostly made up of Uranium that is an energy resource.
The issue is that it's co-mingled with a bunch of nasty stuff. Stuff that generates heat and radioactivity while it decays (which makes handling the used fuel difficult and expensive for reprocessing) and stuff that is a neutron "poison" (meaning it soaks up neutrons, lowering the neutron economy of the fuel).
We have the technology to separate out the good stuff from the bad (France does it in fact) but it is very expensive. At current Uranium prices it's uneconomical - France does it because it believes "it's the right thing to do" (TM). However, in the future we could come up with new reprocessing technology that makes it cheaper (many scientists are working on that) _or_ the price of Uranium could go up to where reprocessing would be economical (although, it may just price nuclear out of the market completely).
One interesting thing: The (failed) Yucca Mountain fuel repository was explicitly designed to allow for retrieval of used fuel. Fuel was to sit on moveable platforms on "train tracks" that would allow both simple placement _and_ retrieval at a later date. This was a "just in case" type deal... at the advent of simplified reprocessing Yucca Mountain would have just been "hanging out" with tons of good stuff that's easily retrievable. All of the other long-term geological repository solutions (like salt-mines and bore-holes) don't have this nice property ;-)
"Uranium reactors, regardless of 'Gen' use fuel that is enriched to about 6%. That means 6% fissionable Uranium, 94% non fissionable."
Two words to learn:
Fissile: Can be easily fissioned with "thermal" neutrons (typically, neutrons around 0.025 eV... also known as "slow" or "low energy" neutrons).
Fissionable: Can fission. Period.
U-235 is "fissile" while U-238 is "fissionable".
The "94%" you talk about (BTW: in the U.S. the limit for enrichment is 5%, most fuel is enriched to 4.8% or so to leave a little bit of headroom) is U-238 and is definitely "fissionable". Several types of reactors have been built over the years that can burn U-238 directly including fast reactors and others that are "high neutron economy" reactors like CANDU, Magnox and AGR which can burn Uranium with very little or no added enrichment.
Fast reactors can work with U-238 because above 1 MeV the fission cross-section for U-238 is large enough (and the capture cross-section simultaneously low enough) that U-238 can sustain the nuclear reaction. This works because neutrons are born with energies ranging from keV up to 20 MeV (although, the average is around 2 MeV).
CANDU can burn natural uranium (Which is only about 0.7% U-235) because of good neutron economy. It utilizes "heavy water" (deuterium/H-2) to slow down the neutrons. H-2 has an almost negligible capture cross-section meaning that nearly all of the neutrons that are born make it down to "thermal" energies where it will fission with U-235. However, since it is still relying on the small amount of U-235 the fuel is depleted fairly quickly, requiring constant refueling (not joking, it is literally refueled continuously). It would certainly be able to burn "spent" light-water reactor fuel though... that "measly" less than 1% (not 3% like you state) enriched stuff would actually be more than the amount of U-235 that typically goes into a CANDU reactor! Of course, some of the built up fission products are neutron poisons, so that would reduce the neutron economy a bit... but it would still be able to maintain a critical reaction.
However, this is not done because it's just not economically feasible. Getting the old fuel from LWRs and shipping it somewhere to be disassembled (which has to be done carefully because when it comes out of the reactor it stays hot (both thermally and radioactivity wise) for quite a while) and put into fuel forms that would work in a CANDU reactor would cost way more than the effort is worth.
It is interesting that you simultaneously insult someone else, screw up a bunch of facts AND manage to make a (terrible) misogynistic joke all in the same post. That certainly undermines your credibility in my eyes...
"But there is no way that you take spend fuel from one reactor and put it into another one and continue burning it there."
That's not exactly true. Just the U-238 that's left in "used" fuel is good enough to sustain a critical reaction in a fast reactor or possibly even a thermal reactor that can utilize natural uranium like CANDU. However, there are many issues that keep this from being a reality (mostly economics).
(Note: I'm not a gun owner, so I'm just speculating)
I think one issue is a general "loss of control".
Guns are about controlling your immediate environment. Being able to respond (with the most basic of responses: physical harm) to threats to yourself and your family.
Anything that threatens to weaken that sense of control is going to have an uphill battle.
What is the end game on "smart guns"? Right now, it's just being used to make sure that the owner is the one firing the gun. In the future? Could it be used to remotely disable the gun?
For instance, many people are pushing for cars to feature a remote "kill switch"... where the police can remotely disable any car just by sending a wireless message to it. Could the same thing be coming to guns?
If smart guns take hold... could you imagine legislation coming down that requires smart guns to be disabled on demand by the police/military? This sounds "great": police roll in to a hostage situation and disable the guns of the assailants and then storm in. However, this may also be a Constitutional violation: is it a restriction on our right to bear arms? Does it give the government the exact authority (to oppress the populace without their ability to stand up to the government with force) the Constitution was trying to protect against?
Like I say: I'm not a gun owner... but that doesn't mean that I can't understand why gun owners would be against this. It's simply about control. Guns don't need to be "smart" to work... adding anything like this is opening the way toward more governmental control that possibly infringes our rights.
Oh - I see now. It's only for Python and R. We're in C++ so no go. Bummer.
How do you get listed? My software project isn't listed. We have a few hundred users and we're nearing about 1000 citations. It's an open source project on GitHub.
How do we tell Depsy about it?
You don't have to mess with your license at all. Scientists are good at citing things if you give them something to cite.
We try to publish a few papers yearly about new aspects of our software... and the scientists that use those pieces of the software naturally cite this papers without issue. We post our citations on our website and many people also email the mailing list to ask for the appropriate thing to cite when they're publishing findings based on our software.
Exactly this. We do the very same.
However, Clang is significantly faster for our application. I would do some timings for you right now... but it takes too damn long to compile the entire stack with GCC ;-) Last time I checked it was on the order of 25% faster. Over a whole day of compiling that can make a big difference.
The fact that, years later, _WE_ are still arguing about this proves that the case has merit.
If WE can't come to a consensus about this... then how is Joe Scmoe supposed to figure it out?
The fact is: this was _misleading_ advertising. They could have easily come up with another name for it (like Intel did with Hyperthreads)... instead they consciously chose to call the extra ALUs _cores_... which does have a meaning to the typical consumer. They did this, on purpose, to muddy the waters... and they REALLY did.
Does that mean that people shouldn't be more careful about what they buy? Sure. But that doesn't absolve AMD from putting out misleading advertising.
Spherical
Exactly right.