That's kind of funny (and expected); I had the opposite experience at the plant. Night shift got things done, and done right! Might have had to do with a much smaller "uh-oh" crowd present in the wee hours.
I agree with you about how doing a meaningful study of this would be difficult. Maybe if the setting were say, in mainland China, which has a more compulsory (read: coercive) culture, then perhaps useful data could be obtained.... hmm....{Flame Proofing ON}
"Shift work" covers a wide range of jobs, from repetitive tasks (as in a factory) to technical support (as in a call center). TFA is really more interested in the disruption of the circadian rhythm because of those types of jobs. What would be interesting is if there was some differentiation in that study according to the types of jobs. Would working at a call center result in a different sort of degradation than, say, assembly? The former engages the brain (according to my firstborn, who seems to enjoy it), while the latter, well, I don't know if I could handle something like that for too long.
And having worked night shifts during our refueling (nuclear plant) outages, I can say that it was never dull, with all manner of problems to solve and people to deal with. There's definitely a nice camaraderie that develops on the night shift, so the term "anti-social" didn't quite apply.
I second. Drills are the way to identify and correct flaws, as well as to identify areas for improvement. It is unfortunate that it took a one-two punch to turn around Japan's nuclear culture, but hopefully they come out stronger, as we had following the Three Mile Island Unit 2 event in 1979. Here in the U.S., even now, emergency drills at nuclear power plants continue to optimize emergency processes, and to test a plant's (including and especially its staff's) response to a significant adverse event. The typical drill postulates a series of malfunctions that inevitably lead to a radiation release, which then triggers an evacuation. This latter part is designed to exercise local and state resources as well.
After Fukushima, the paradigm got turned a bit on its head: instead of a nuclear plant event causing the emergency, it's a natural calamity that degrades and destroys infrastructure that could lead to a radiation release. As a result, the lessons learned prompted at least one order, which requires all U.S. plants to be ready for events that are beyond their current design bases. In other words, if your plant was designed for a Category 3 hurricane, be ready to handle one that's much more devastating. As you might expect, this is no small expense, but the U.S utilities have committed to making the preparations, and you can find descriptions of these on the NRC website.
Amen to that. I've told my kids that their parents have jobs: I am the breadwinner, while mom manages the household. It is therefore their job to attend school. I get performance reviews at work (while mom is of course, exempt from such:D). It is therefore important for them to do well at school, and grades, like it or not, reflect that progress.
Seems to me that the financial incentive has two functions: while it can clearly be a motivator (that likely promotes only short-term and shallow learning; but that's another discussion), it is also an indicator of how parents value (or de-value) education.
I admire your effort and appreciate the apparent pro-nuclear stance. But please check out the NRC Fact Sheet on TMI Unit 2 (Unit 1 is doing just fine, thanks) for more precise details on the cause and sequence of events for the accident. You'll find some useful facts that will correct some of your misconceptions about the contributing factors and root causes of the event.
In my opinion, the most dominant root cause was inadequate operator training. The stuck-open primary valve (PORV) was misdiagnosed, with a faulty valve position indicator contributing to the misdiagnosis. Every operator action taken downstream of that led to the circus surrounding the event. It did not do to create emergency operating guidance on the fly. I contend that if there was no operator interference with the Emergency Core Cooling System(s) (yes, there are several), the core would have remained intact for some time (days).
BTW, SDM stands for Shutdown Margin - at least in the civilian side of the nuke industry.:D
"1. Initially from a computer forensics pov, it would be trivial to detect if a video has been altered, however i think with further improvements in the embedding technology where the actual advert piece is better rendered to take into account surrounding lighting conditions it might become more difficult, however not impossible to detect intentional modifications"
If I'd points, I'd mod you insightful - and I appreciate the understated tone of the statement. One implied (er, embedded) concern here is the legal standing of video evidence, say from ATM or other security surveillance cameras. A new and probably more intense layer of forensics will have to be added to validate such evidence. I foresee a mess (but I hope I'm wrong).
"Yes, we provide necessary infrastructure support so the company *can* make money, but the companies that succeed will be those that find ways to control those back-end costs."
Indeed, such as by transitioning to less manpower-intensive operating systems, like Linux.
I applaud your courage to be an apostate - and as you can see, the Slashdot crowd gave you a series of reactions ranging from personal attacks (Do you pray 5 times a day?) to denial (You're overestimating the extremists' chances!); only a few, including me, agree with you.
If history is any indicator, the rise of any extreme movement starts out as a splinter group that may or may not gain traction. With the Nazis, who started out as a bunch of disgruntled WWI veterans, opportunists, and so on, the appeal was economic: the trains WILL run on time, and once the Jewish Problem is solved, then prosperity and glory for all.
In the case of the Wahabbi movement, the promise is that of eternal paradise, dominion over women, etc. These have strong appeal to the educated, bored and overfunded, and to the ignorant, angry and poor. A pretty broad spectrum of appeal, if you think about it. And all that is required for these types of movements to succeed is for NO ONE to stand up to them.
For all his faults, Kemal Ataturk was wise to chose the secular path for your country. Again, I admire your choice and wish you the best.
If you want to think of it that way, I suppose. The pouring is certainly part of the casting process. What makes a forging a forging is the compressive load applied to strengthen the ingot (hence the aligned lattices), while castings are usually machined to shape post-pour, or given its finish.
Ah yes, Tsuruga. The BWRs employ a different structure for their core supports, but the principle is the same as the lugs (also welded, but are not the only internals of note) inside a PWR. For both types of reactors, intergranular stress corrosion cracking (IGSCC) and its cousin, primary water stress corrosion cracking (PWSCC) have been a problem. Both are mitigated by replacing the weldment with Alloy 52/152 and Alloy 690, where applicable. Alloy 600 and 82/182 have proven to not be the wonder alloys they were thought to be. The Electric Power Research Institute and the industry as a whole made big moves to remove, repair, or otherwise mitigate these problem metals from the most susceptible locations.
"...although in internal reactor components welded to the shell, not the shell itself."
I think you may be a bit misinformed here. The internals of a reactor are not welded to the "pot" itself. Instead, these structures rest on lugs or other cantilever-like structures that permit the stacking of these internals. For example, the core, which consists of some number of fuel assemblies (depends on design), sits on top of a lower grid structure, and a core flow distributor that ensures as even an inlet coolant flow as possible. The distributor itself rests on these lugs. The core barrel surrounds the core, and then there's an upper plenum barrel and upper guide structure for the control rods. These are all held in place by their weight, and at the vessel flange level, the whole shooting match is clamped by studs on the reactor vessel and the upper head flanges. These are all removable to facilitate a visual and ultrasonic inspection every 10 years, as required by ASME code.
"The environment of a reactor pressure vessel is tough."
Neat choice of words. Toughness is a reactor vessel property that has an associated criterion in the US Title 10 Code of Federal Regulations, Part 50 Appendix G. Given a tough environment, you need a tough vessel.
"...Then there's corrosion. There have been major corrosion problems requiring reactor shutdowns from carbon dioxide..."
Ah, you appear to be speaking of European designs then (i.e., Magnox), but I am curious of how CO2 is causing corrosion. For US pressurized water reactors, the concern is oxygen, which is scavenged by keeping the reactor coolant hydrogenated.
"Remember, this is a steam pressure vessel; at steam temperatures and pressures, minor corrosive effects at room temperature become big problems."
Not all vessels are intended for steam production. Boiling Water Reactor vessels, certainly, but not PWRs.
"Then there's the problem of approach angle - welding on a vertical surface is not easy."
True, but that's why a lot of large geometry welding is automatic, with jigs set up to guide and control the weld deposition.
Good question. Just so you know, the pressure vessels of nuclear reactors are not one-piece construction. They are rolled carbon steel plates joined by longtitudinal and circumferential welds (for commercial pressurized water reactors, the inner surfaces are clad with stainless steel; the boilers, I think they're unclad). Upper and lower hemispherical heads are separate pieces, with the lower one welded to the barrel of the vessel, and the upper one being flanged and bolted to facilitate removal, so that fuel assemblies can be replaced.
One problem with casting (that's a lot of wax to lose!:D) is assuring uniformity, especially with really large pieces. Voids or other flaws, detected by radiography, are a big no-no, and imagine having to reject a whole cast vessel on that basis, as opposed to a rolled plate.
You correctly point out the strength issue: a pressurized water reactor operates at about 2200 psia, and the forging process imparts the needed strength for those, as well as emergency, conditions. I don't recall from my old manufacturing engineering class what the yield strength/weight ratio is for forgings vs castings, but I recall it being significant.
Oh, a variety of reasons: labor costs, liability, NIMBY. When these pile up to make the product more costly, those off-shore options look very attractive. Also, remember when Datsuns and Toyotas were looked down upon as motorized recycled beer cans? Well, it turns out that recycling pre-manufactured metals is pretty efficient, not to mention environmentally less destructive.
However, as a poster above noted, once the financial incentive is there, someone else will build, or better yet, resurrect mothballed steelmaking facilities to match the demand JSW's trying to meet. The only concern in the nuclear industry now is if the US government gets cold feet. Especially from a potentially hostile - or even mildly apathetic - Democratic (sad, but true) administration. This will disincentivize the effort, and the US will once again, as it historically has, let other countries master the technology (e.g., post-WWI: aircraft; 1970s: cars; 1980s: electronics; 2000s: nukes?) it originally pioneered.
"...Come a day there won't be room for naughty men like us to slip about at all. This job goes south, there well not be another. So here's us, on the raggedy edge."
Interesting article, thanks. And it was nice of the paper to discuss the Oklo phenomenon. As far as the area around the earth's core being a nuclear reactor in the sense of maintaining a critical mass and critical geometry, I think that, at best the criticality is transient and unstable, going from subcritical to supercritical and vice-versa, given the dynamic nature of the fluid.
Another fascinating observation from the paper is the dominance of the U235/U238 ratios, and how U235 (the fissile isotope) was at a higher (3%) abundance in the past, versus the 0.7% today. BTW, that 3% value is about the U235 enrichment level in commercial reactor fuel in the U.S (YMMV). Finally, at the other end of this rambling hypothesis is that the area has a high concentration of radioisotopes that emit all sorts of radiation (and hence, heat). Not as exciting, but still interesting nonetheless.
I thought it was just me who had this problem, if you want to call it that.
I never had any serious music lessons in the past, so I started learning how to play the piano two years ago. On paper, my teacher has me at Level 3 (for kids, generally) for theory and lesson books, but she has, and is, pushing the performance aspect. She found that I progressed pretty quickly, and has me trying out pieces at Level 6, with 'Fur Elise' as the current project (my fingers ache just thinking about it).
I find myself developing the muscle memory after about 5-8 hours of intermittent practice. When I get the movements down, I go on autopilot, and usually perform well (I do need to work on counting: I count too quickly). The downside is that this form of memorization has not improved my sight reading ability at all. I think it has actually degraded it.
So ironically, what I perceived to be a multi-tasking exercise (read music + play it, sort of like an interpreted program), ends up being a single task (it's compiled: jes' play it, son).
...
Collector: [as he's being dragged away by Security Guard] Hey wait a second! He jumped me, you fucking tracer!
Banky: YOUR MOTHER'S A TRACER!
Collector: DON'T TRACE ME, BRO!
In my opinion, the above sums up the relationship of art to an individual. I've posted before that I can't abide most abstract art of any sort (music, paintings, sculture, etc.), since demonstrated skill is what counts with me. But there are exceptions, but as a rule, and unfortunately, I tend to forget them as I walk away.
Art's importance to a person is instinctive and perhaps more importantly, transient.
Slashdot Mirror
...about Worlds Colliding?
Yes, there was: The Pool Guy> .
"Way lower production, too..."
That's kind of funny (and expected); I had the opposite experience at the plant. Night shift got things done, and done right! Might have had to do with a much smaller "uh-oh" crowd present in the wee hours.
I agree with you about how doing a meaningful study of this would be difficult. Maybe if the setting were say, in mainland China, which has a more compulsory (read: coercive) culture, then perhaps useful data could be obtained.... hmm....{Flame Proofing ON}
"Shift work" covers a wide range of jobs, from repetitive tasks (as in a factory) to technical support (as in a call center). TFA is really more interested in the disruption of the circadian rhythm because of those types of jobs. What would be interesting is if there was some differentiation in that study according to the types of jobs. Would working at a call center result in a different sort of degradation than, say, assembly? The former engages the brain (according to my firstborn, who seems to enjoy it), while the latter, well, I don't know if I could handle something like that for too long.
And having worked night shifts during our refueling (nuclear plant) outages, I can say that it was never dull, with all manner of problems to solve and people to deal with. There's definitely a nice camaraderie that develops on the night shift, so the term "anti-social" didn't quite apply.
I second. Drills are the way to identify and correct flaws, as well as to identify areas for improvement. It is unfortunate that it took a one-two punch to turn around Japan's nuclear culture, but hopefully they come out stronger, as we had following the Three Mile Island Unit 2 event in 1979. Here in the U.S., even now, emergency drills at nuclear power plants continue to optimize emergency processes, and to test a plant's (including and especially its staff's) response to a significant adverse event. The typical drill postulates a series of malfunctions that inevitably lead to a radiation release, which then triggers an evacuation. This latter part is designed to exercise local and state resources as well.
After Fukushima, the paradigm got turned a bit on its head: instead of a nuclear plant event causing the emergency, it's a natural calamity that degrades and destroys infrastructure that could lead to a radiation release. As a result, the lessons learned prompted at least one order, which requires all U.S. plants to be ready for events that are beyond their current design bases. In other words, if your plant was designed for a Category 3 hurricane, be ready to handle one that's much more devastating. As you might expect, this is no small expense, but the U.S utilities have committed to making the preparations, and you can find descriptions of these on the NRC website.
Agree on the amazing nature of the scene. The music, however, is the first verse of Psalm 115, "Non Nobis Domine." Lyrics here: http://www.lyricstime.com/steve-green-no-nobis-domine-lyrics.html
I'd mod you Interesting, but I'd previously replied to a comment upstream. All war is deception, indeed.
..and it moved to Hernando to play in Class 3 day.
I used to work there. Good people.
Amen to that. I've told my kids that their parents have jobs: I am the breadwinner, while mom manages the household. It is therefore their job to attend school. I get performance reviews at work (while mom is of course, exempt from such :D). It is therefore important for them to do well at school, and grades, like it or not, reflect that progress.
Seems to me that the financial incentive has two functions: while it can clearly be a motivator (that likely promotes only short-term and shallow learning; but that's another discussion), it is also an indicator of how parents value (or de-value) education.
Obfuscant,
I'm afraid the Plame-outing meme has stuck on, hard. Repeat a story enough and it is taken to be true in its entirety.
SDM,
:D
I admire your effort and appreciate the apparent pro-nuclear stance. But please check out the NRC Fact Sheet on TMI Unit 2 (Unit 1 is doing just fine, thanks) for more precise details on the cause and sequence of events for the accident. You'll find some useful facts that will correct some of your misconceptions about the contributing factors and root causes of the event.
In my opinion, the most dominant root cause was inadequate operator training. The stuck-open primary valve (PORV) was misdiagnosed, with a faulty valve position indicator contributing to the misdiagnosis. Every operator action taken downstream of that led to the circus surrounding the event. It did not do to create emergency operating guidance on the fly. I contend that if there was no operator interference with the Emergency Core Cooling System(s) (yes, there are several), the core would have remained intact for some time (days).
BTW, SDM stands for Shutdown Margin - at least in the civilian side of the nuke industry.
"1. Initially from a computer forensics pov, it would be trivial to detect if a video has been altered, however i think with further improvements in the embedding technology where the actual advert piece is better rendered to take into account surrounding lighting conditions it might become more difficult, however not impossible to detect intentional modifications"
If I'd points, I'd mod you insightful - and I appreciate the understated tone of the statement. One implied (er, embedded) concern here is the legal standing of video evidence, say from ATM or other security surveillance cameras. A new and probably more intense layer of forensics will have to be added to validate such evidence. I foresee a mess (but I hope I'm wrong).
"Yes, we provide necessary infrastructure support so the company *can* make money, but the companies that succeed will be those that find ways to control those back-end costs."
Indeed, such as by transitioning to less manpower-intensive operating systems, like Linux.
I applaud your courage to be an apostate - and as you can see, the Slashdot crowd gave you a series of reactions ranging from personal attacks (Do you pray 5 times a day?) to denial (You're overestimating the extremists' chances!); only a few, including me, agree with you.
If history is any indicator, the rise of any extreme movement starts out as a splinter group that may or may not gain traction. With the Nazis, who started out as a bunch of disgruntled WWI veterans, opportunists, and so on, the appeal was economic: the trains WILL run on time, and once the Jewish Problem is solved, then prosperity and glory for all.
In the case of the Wahabbi movement, the promise is that of eternal paradise, dominion over women, etc. These have strong appeal to the educated, bored and overfunded, and to the ignorant, angry and poor. A pretty broad spectrum of appeal, if you think about it. And all that is required for these types of movements to succeed is for NO ONE to stand up to them.
For all his faults, Kemal Ataturk was wise to chose the secular path for your country. Again, I admire your choice and wish you the best.
If you want to think of it that way, I suppose. The pouring is certainly part of the casting process. What makes a forging a forging is the compressive load applied to strengthen the ingot (hence the aligned lattices), while castings are usually machined to shape post-pour, or given its finish.
Ah yes, Tsuruga. The BWRs employ a different structure for their core supports, but the principle is the same as the lugs (also welded, but are not the only internals of note) inside a PWR. For both types of reactors, intergranular stress corrosion cracking (IGSCC) and its cousin, primary water stress corrosion cracking (PWSCC) have been a problem. Both are mitigated by replacing the weldment with Alloy 52/152 and Alloy 690, where applicable. Alloy 600 and 82/182 have proven to not be the wonder alloys they were thought to be. The Electric Power Research Institute and the industry as a whole made big moves to remove, repair, or otherwise mitigate these problem metals from the most susceptible locations.
"...although in internal reactor components welded to the shell, not the shell itself."
I think you may be a bit misinformed here. The internals of a reactor are not welded to the "pot" itself. Instead, these structures rest on lugs or other cantilever-like structures that permit the stacking of these internals. For example, the core, which consists of some number of fuel assemblies (depends on design), sits on top of a lower grid structure, and a core flow distributor that ensures as even an inlet coolant flow as possible. The distributor itself rests on these lugs. The core barrel surrounds the core, and then there's an upper plenum barrel and upper guide structure for the control rods. These are all held in place by their weight, and at the vessel flange level, the whole shooting match is clamped by studs on the reactor vessel and the upper head flanges. These are all removable to facilitate a visual and ultrasonic inspection every 10 years, as required by ASME code.
"The environment of a reactor pressure vessel is tough."
Neat choice of words. Toughness is a reactor vessel property that has an associated criterion in the US Title 10 Code of Federal Regulations, Part 50 Appendix G. Given a tough environment, you need a tough vessel.
"...Then there's corrosion. There have been major corrosion problems requiring reactor shutdowns from carbon dioxide..."
Ah, you appear to be speaking of European designs then (i.e., Magnox), but I am curious of how CO2 is causing corrosion. For US pressurized water reactors, the concern is oxygen, which is scavenged by keeping the reactor coolant hydrogenated.
"Remember, this is a steam pressure vessel; at steam temperatures and pressures, minor corrosive effects at room temperature become big problems."
Not all vessels are intended for steam production. Boiling Water Reactor vessels, certainly, but not PWRs.
"Then there's the problem of approach angle - welding on a vertical surface is not easy."
True, but that's why a lot of large geometry welding is automatic, with jigs set up to guide and control the weld deposition.
Good question. Just so you know, the pressure vessels of nuclear reactors are not one-piece construction. They are rolled carbon steel plates joined by longtitudinal and circumferential welds (for commercial pressurized water reactors, the inner surfaces are clad with stainless steel; the boilers, I think they're unclad). Upper and lower hemispherical heads are separate pieces, with the lower one welded to the barrel of the vessel, and the upper one being flanged and bolted to facilitate removal, so that fuel assemblies can be replaced.
:D) is assuring uniformity, especially with really large pieces. Voids or other flaws, detected by radiography, are a big no-no, and imagine having to reject a whole cast vessel on that basis, as opposed to a rolled plate.
One problem with casting (that's a lot of wax to lose!
You correctly point out the strength issue: a pressurized water reactor operates at about 2200 psia, and the forging process imparts the needed strength for those, as well as emergency, conditions. I don't recall from my old manufacturing engineering class what the yield strength/weight ratio is for forgings vs castings, but I recall it being significant.
Hope this helps.
Oh, a variety of reasons: labor costs, liability, NIMBY. When these pile up to make the product more costly, those off-shore options look very attractive. Also, remember when Datsuns and Toyotas were looked down upon as motorized recycled beer cans? Well, it turns out that recycling pre-manufactured metals is pretty efficient, not to mention environmentally less destructive.
However, as a poster above noted, once the financial incentive is there, someone else will build, or better yet, resurrect mothballed steelmaking facilities to match the demand JSW's trying to meet. The only concern in the nuclear industry now is if the US government gets cold feet. Especially from a potentially hostile - or even mildly apathetic - Democratic (sad, but true) administration. This will disincentivize the effort, and the US will once again, as it historically has, let other countries master the technology (e.g., post-WWI: aircraft; 1970s: cars; 1980s: electronics; 2000s: nukes?) it originally pioneered.
"...Come a day there won't be room for naughty men like us to slip about at all. This job goes south, there well not be another. So here's us, on the raggedy edge."
Ironically, found using Google.
Interesting article, thanks. And it was nice of the paper to discuss the Oklo phenomenon. As far as the area around the earth's core being a nuclear reactor in the sense of maintaining a critical mass and critical geometry, I think that, at best the criticality is transient and unstable, going from subcritical to supercritical and vice-versa, given the dynamic nature of the fluid.
Another fascinating observation from the paper is the dominance of the U235/U238 ratios, and how U235 (the fissile isotope) was at a higher (3%) abundance in the past, versus the 0.7% today. BTW, that 3% value is about the U235 enrichment level in commercial reactor fuel in the U.S (YMMV). Finally, at the other end of this rambling hypothesis is that the area has a high concentration of radioisotopes that emit all sorts of radiation (and hence, heat). Not as exciting, but still interesting nonetheless.
I thought it was just me who had this problem, if you want to call it that.
I never had any serious music lessons in the past, so I started learning how to play the piano two years ago. On paper, my teacher has me at Level 3 (for kids, generally) for theory and lesson books, but she has, and is, pushing the performance aspect. She found that I progressed pretty quickly, and has me trying out pieces at Level 6, with 'Fur Elise' as the current project (my fingers ache just thinking about it).
I find myself developing the muscle memory after about 5-8 hours of intermittent practice. When I get the movements down, I go on autopilot, and usually perform well (I do need to work on counting: I count too quickly). The downside is that this form of memorization has not improved my sight reading ability at all. I think it has actually degraded it.
So ironically, what I perceived to be a multi-tasking exercise (read music + play it, sort of like an interpreted program), ends up being a single task (it's compiled: jes' play it, son).
You forgot:
...
Collector: [as he's being dragged away by Security Guard] Hey wait a second! He jumped me, you fucking tracer!
Banky: YOUR MOTHER'S A TRACER!
Collector: DON'T TRACE ME, BRO!
In my opinion, the above sums up the relationship of art to an individual. I've posted before that I can't abide most abstract art of any sort (music, paintings, sculture, etc.), since demonstrated skill is what counts with me. But there are exceptions, but as a rule, and unfortunately, I tend to forget them as I walk away.
Art's importance to a person is instinctive and perhaps more importantly, transient.
Give it 20 years. It will be too cheap to meter. :D