The reservoir at the top of the AP1000 is used to provide evaporative cooling to the outer shell of the containment structure. After 3 days the decay heat has reduced to around 0.2% of the original power. At this point convective and radiative cooling of the containment vessel is sufficient to dissipate the heat generated from nuclear decays in the fuel. The water within the containment vessel just circulates within the structure and is driven by the heat of the nuclear fuel. It is never vented.
The decay was an atom splitting into two smaller atoms and energy, which is fission. From the three dictionaries I looked up, "decay, not fission" is a contradiction, as the decay in question was necessarily *also* fission.
No. The decays in question occur when a neutron within fission product (the nuclei created after the U235) converts into proton together with an electron and a neutrino. Each decay releases around 1 MeV of energy (order of magnitude) as opposed the 200 MeV from the fission process. The processes reduces in intensity in time. Right after a scram the "decay heat" is 7% of the full power of the reactor. After 3 days it reduces to around 0.2% of the original power.
The question was of why would fukishima need active cooling when passive cooling is so "easy" to do.
It was by no means easy to design an economical reactor with the kind of passive safety cooling provided by the AP1000. I can imagine why you think it was.
I think this is part of a cross licensing strategy that could finally make Apple stop being so stupid. The rest of the phone world has patents on tech that Apple employs. The rest of the phone world has FRAND'ed those patents. My guess is that this stuff is trying to force Apple to give up it's own small improvements related to iPhones and iPads as being world-changing tech available only to them.
Yeah I commented on an earlier article about how much better off we are with Google and Android. I got weirdest set of hate comments. People hate getting their prejudices refuted. It causes massive cognitive dissonance and is physically painful. I have my own and have observed the effect on me.
MS Office is the defacto standard. I need it to inter-operate in my workplace.
Despite all the progress made by AbiWord and even LibreOffice they're still not good enough at interoperability.
On the other hand http://abicollab.net/ offers a different and genuine way around it. Once you do real real-time collaboration in the cloud, emailing MS Office docs around seems pretty stupid.
There is a hell of a lot of whining about GNOME 3 here. I'm a free software developer of desktop software (AbiWord). I personally like GNOME 3 and its approach to do a new take on how best to present a computer interface to users. I also maintain systems for my mother and daughter who are definitely not computer geeks. They're both impressed and comfortable with GNOME 3.
So my extremely small sample imply that GNOME 3 is a good step. For the computers geeks out there there a plenty of alternatives. Find the one that works for you.
Achieving 6c/KWHr for baseload ie available any time you want it 24 hours a day, with solar is a fundamentally hard problem. You're up against the 2nd law of thermodynamics. Solar energy is both dilute and intermittent.
Nuclear is far easier. It is starts out incredibly concentrated. Third generation plants like the AP1000 are extremely safe. If you don't want to reuse the waste it's easy enough to bury it 1 km underground where it won't bother anyone.
It's far easier to change the minds of people than the laws of Physics.
Looks like the USA and Europe will leave it to China to develop cheap nukes and become the driver of human civilization in the 21st century.
I have a Lenovo Thinkpad 200XS (128G SSD) running Fedora 15. No problems at all. Very light, 6 hour battery life. Runs cool and very quiet. Just wish I had more pixels (1280x800).
I run windows in VMWare for MS Office stuff. MSOffice presentations "just work" when you set the windows VM to 1024x768.
5+ hours of CPU time for a single build, 25+ minutes of wall time, as measured on a workstation (dual-E5620 i.e. 2x quad-core 2.4GHz HT, with 24GB of RAM, no SSD)
25 minutes of wall time is nothing for a first build. After that updates from changes in the source code will be trivial.
25 minutes to build a complete linux distro is fantastic.
Utter fearmongering nonsense. Neutrons occur naturally everywhere as secondary particles from cosmic rays.
yes you are right this "background" radiation does occur naturally and no your are wrong their is reason to fear as their is no known safe level of radiation.
This so called "natural" radiation is thought to be the causes of some cancers.
"...most scientists and regulatory agencies agree that even small doses of ionizing radiation increase cancer risk, although by a very small amount. In general, the risk of cancer from radiation exposure increases as the dose of radiation increases. Likewise, the lower the exposure is, the smaller the increase in risk. But there is no threshold below which ionizing radiation is thought to be totally safe."
Maybe, but the risk is utterly not worth worrying about. Every second of your life you have ~5000 decays of potassium 40 within your body. If you were to remove that potassium you would die. A few tens of becquerels of extra radiation external to your body is a ridiculously small extra risk.
Now the source code to android is open everyone on the planet can get IOS features (and more). We're way ahead because of Google.
No need to be an apologist for Apple. They've got enough cash to keep you in new shiny gadgets for at least 10 years. The rest of us can build and play with linux and android.
This experiment required creating a new proton extraction point, target, meson focussing magnet and meson decay tunnel. The focussing element and tunnel were pointed in the direction of the Gran Sasso laboratory. The Italian funding agency paid a large fraction of these including the meson decay tunnel. The tunnel provides time for the mesons to decay to the neutrinos and is a few hundred meters long and directed downwards towards Gran Sasso. The experiment would not have been successful without the decay tunnel.
I don't speak Italian so I don't know this is what was meant...
I write a lot of GPL'd code. I am extremely comfortable with the license. Frankly all these complaints about the GPL sound like sour grapes from the developers who want to rip off the wonderful and ever-growing collection of software commons we've been developing over the years.
Don't like it? Stay in your own little pool and not the ocean we've created.
The weird thing is that some people think this will be a failure because of possible natural disasters and people possibly not being able to read this clock etcetera, and get hissy fits about it, while the many of the same people don't mind at all that really, REALLY, REALLY!! dangerous nuclear waste has to be safely disposed of for about 25 times as long as the period this clock is designed for and still insist nuclear energy is safe.
People are weird!
There are many, many toxic substances in the earth. Many of these will will be dangerous long after Nuclear waste has decayed to the point where it's radioactivity is well below background levels.
Slashdot Mirror
The reservoir at the top of the AP1000 is used to provide evaporative cooling to the outer shell of the containment structure.
After 3 days the decay heat has reduced to around 0.2% of the original power. At this point convective and radiative cooling of the containment vessel is sufficient to dissipate the heat generated from nuclear decays in the fuel. The water within the containment vessel just circulates within the structure and is driven by the heat of the nuclear fuel. It is never vented.
No. The decays in question occur when a neutron within fission product (the nuclei created after the U235) converts into proton together with an electron and a neutrino. Each decay releases around 1 MeV of energy (order of magnitude) as opposed the 200 MeV from the fission process. The processes reduces in intensity in time. Right after a scram the "decay heat" is 7% of the full power of the reactor. After 3 days it reduces to around 0.2% of the original power.
It was by no means easy to design an economical reactor with the kind of passive safety cooling provided by the AP1000. I can imagine why you think it was.
I think this is part of a cross licensing strategy that could finally make Apple stop being so stupid. The rest of the phone world has patents on tech that Apple employs. The rest of the phone world has FRAND'ed those patents. My guess is that this stuff is trying to force Apple to give up it's own small improvements related to iPhones and iPads as being world-changing tech available only to them.
We'll see.
Yeah I commented on an earlier article about how much better off we are with Google and Android. I got weirdest set of hate comments. People hate getting their prejudices refuted. It causes massive cognitive dissonance and is physically painful. I have my own and have observed the effect on me.
Yes indeed! This is exactly what I do. I run Windows 7 in a VM on my linux workstation. Unfortunately this still means I run windows :-(
MS Office is the defacto standard. I need it to inter-operate in my workplace.
Despite all the progress made by AbiWord and even LibreOffice they're still not good enough at interoperability.
On the other hand http://abicollab.net/ offers a different and genuine way around it. Once you do real real-time collaboration in the cloud, emailing MS Office docs around seems pretty stupid.
(Disclaimer AbiWord and http://abicollab.net/ are my babies)
There is a hell of a lot of whining about GNOME 3 here. I'm a free software developer of desktop software (AbiWord). I personally like GNOME 3 and its approach to do a new take on how best to present a computer interface to users. I also maintain systems for my mother and daughter who are definitely not computer geeks. They're both impressed and comfortable with GNOME 3.
So my extremely small sample imply that GNOME 3 is a good step. For the computers geeks out there there a plenty of alternatives. Find the one that works for you.
Achieving 6c/KWHr for baseload ie available any time you want it 24 hours a day, with solar is a fundamentally hard problem. You're up against the 2nd law of thermodynamics. Solar energy is both dilute and intermittent.
Nuclear is far easier. It is starts out incredibly concentrated. Third generation plants like the AP1000 are extremely safe. If you don't want to reuse the waste it's easy enough to bury it 1 km underground where it won't bother anyone.
It's far easier to change the minds of people than the laws of Physics.
Looks like the USA and Europe will leave it to China to develop cheap nukes and become the driver of human civilization in the 21st century.
I have a Lenovo Thinkpad 200XS (128G SSD) running Fedora 15. No problems at all. Very light, 6 hour battery life. Runs cool and very quiet. Just wish I had more pixels (1280x800).
I run windows in VMWare for MS Office stuff. MSOffice presentations "just work" when you set the windows VM to 1024x768.
TFA says:
25 minutes of wall time is nothing for a first build. After that updates from changes in the source code will be trivial.
25 minutes to build a complete linux distro is fantastic.
Utter fearmongering nonsense. Neutrons occur naturally everywhere as secondary particles from cosmic rays.
yes you are right this "background" radiation does occur naturally and no your are wrong their is reason to fear as their is no known safe level of radiation.
This so called "natural" radiation is thought to be the causes of some cancers.
"...most scientists and regulatory agencies agree that even small doses of ionizing radiation increase cancer risk, although by a very small amount. In general, the risk of cancer from radiation exposure increases as the dose of radiation increases. Likewise, the lower the exposure is, the smaller the increase in risk. But there is no threshold below which ionizing radiation is thought to be totally safe."
http://www.cancer.org/Cancer/CancerCauses/OtherCarcinogens/MedicalTreatments/radiation-exposure-and-cancer
Maybe, but the risk is utterly not worth worrying about. Every second of your life you have ~5000 decays of potassium 40 within your body. If you were to remove that potassium you would die. A few tens of becquerels of extra radiation external to your body is a ridiculously small extra risk.
http://en.wikipedia.org/wiki/Potassium-40
Google + android = open source fail.
At least with Apple you generally know where you stand.........(what did I just say!??)
Steve Jobs says:'I'm going to destroy Android': - Jobs declared 'thermonuclear war' on Google
http://www.theage.com.au/technology/technology-news/im-going-to-destroy-android-jobs-declared-thermonuclear-war-on-google-20111021-1mbaq.html#ixzz1bPhM8NJY
Now the source code to android is open everyone on the planet can get IOS features (and more). We're way ahead because of Google.
No need to be an apologist for Apple. They've got enough cash to keep you in new shiny gadgets for at least 10 years. The rest of us can build and play with linux and android.
With one free plugin it becomes worthless information with no advertising.
Or if you're in the entertainment or media business, it can become useful information with no advertising.
http://www.adblockplus.com/
Mod parent up! No more ads to remove stomach fat :-)
I live oz and just downloaded it to my HTC legend running android 2.2
I'm on a vodafone plan but my internet connection is through optus cable.
BTW this is one really fun app! The 3D controls are great :-)
You assume the price of petrol will stay at $4/gal over the next 6 years.
Works fine on this machine. F15 with gnome-3 and NVIDIA. This is a really nice workstation.
*shrugs*
This experiment required creating a new proton extraction point, target, meson focussing magnet and meson decay tunnel. The focussing element and tunnel were pointed in the direction of the Gran Sasso laboratory. The Italian funding agency paid a large fraction of these including the meson decay tunnel. The tunnel provides time for the mesons to decay to the neutrinos and is a few hundred meters long and directed downwards towards Gran Sasso. The experiment would not have been successful without the decay tunnel.
I don't speak Italian so I don't know this is what was meant...
Did you get paid to write that?
http://msevior.livejournal.com/30816.html
http://arxiv.org/abs/1109.4897v1
I write a lot of GPL'd code. I am extremely comfortable with the license. Frankly all these complaints about the GPL sound like sour grapes from the developers who want to rip off the wonderful and ever-growing collection of software commons we've been developing over the years.
Don't like it? Stay in your own little pool and not the ocean we've created.
Congrats Guys!
This is lovely Science. From this I guess we can map the underlying topology of Antarctica.
I kind of like it now. What bothers me most is the work I have to go through to open a new version of a running program on a new workspace.
There are many, many toxic substances in the earth. Many of these will will be dangerous long after Nuclear waste has decayed to the point where it's radioactivity is well below background levels.
http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor
To quote you. I agree, people are weird.
... violence doesn't hurt.
Compared to emotional pain, I totally agree.