More circuits == more copper, no matter how thin the wiring is. It's also substantially more labour cost to install, test and maintain.
When you double the voltage to 230V, you can get _four times_ the power from the same resistance - and voltage losses aren't as critical (20V drop on a 230 circuit is no big deal, but it's a big problem on 110V)
110V is annoying to work with because it has so many restrictions. It's no safer than 230V and coupled with more lax wiring regulations you have a much higher rate of electrocutions in the USA than in the EU.
FWIW, the wiring in your "high power" circuits is much heavier than is used in most european circuits - the standard for most outlet circuits is 2.5mm^2, with 4mm^2 being used on long runs or 32A circuits.
"By cladding an ASME Type III structural alloy (Alloy 617 or Alloy 800H) with a corrosion resistant layer (perhaps Hastelloy-N modified with 1.5% Niobium) you can provide the high temperature strength and corrosion resistance that advanced high performance LFTRs will require."
That problem has been solved for decades.
The USA nuclear industry keeps going with old designs for the most part because
1: that's all they're allowed to go with. 2: There haven't been any new nuclear plants online to speak of since TMI (none of the "new builds" are online yet and those were almost all started over 30 years ago in any case. TMI effectively put a halt to any unfinished systems, midbuild) 3: Accountants don't like R&D. They'd far rather run with something that works but is dangerous than something which is "untested" but is a lot safer. 4: LTFRs don't produce much weapons-grade plutonium (way down on conventional plants), which the US govt didn't like because it means the "waste" can't be mined for bombs - this is why the USA shut down LFTR research in 1972
Since the 1970s, All the R&D for alternative commercial designs has occurred in other parts of the world. Tinkering with water/steam pressure isn't new technology, nor is setting things up so that the the reactors can passively SCRAM. It's just better engineering. The fact remains that pressurised reactor systems are intrinsically dangerous, as are sodium cooled plants. Lead based systems work but are still based on fuel rods and have proven fairly unreliable in service.
The only serious issue with LFTRs has turned out to be long-term (30 year) storage of cold salts and only because nobody bothered removing the "hot stuff" when the test program finished in 1969. Once the issue was realised and the radioactives extracted, the salts have been stable and no longer require periodic melting/flowing to extract gas buildups.
"Consider the situation of mining REEs in the USA. There is no shortage of them here, but the mines were all closed due to price depression"
The price depression was because US miners had to deal with toxic extraction byproducts and ensure a mildly radioactive material wasn't allowed to enter the biosphere, whilst chinese producers didn't have to worry about the environment.
Now the chinese miners do have to worry, with tougher environmental protection rules being enacted and enforfced.
That radioactive substance? Thorium.
There is enough thorium _already_ mined and sitting in mine tailings to meet current world power demands for a few decades, if not centuries.
Given that it takes 250 tonnes of mined uranium (1% U235) to produce 143 tonnes of fuel grade uranium (3% U235) and the end result is 142 tonnes of nuclear waste, the thought of mining 1 tonne of thorium, to go straight into the fuel cycle and the end product is ~15kg of nuclear waste (yes really) to get the same amount of electricity out (probably more as LFTRs run hotter, which translates to better thermodynamic efficiency) with a system which is intrinisicaly safe on the nuclear side (no steam explosions, metal fires or meltdowns), It's no wonder thorium is attractive. That it can burn down uranium plant "nuclear waste" is an added bonus (a thorium plant needs U233 or other source to get started, but once running it transmutes thorium to plutonium and U233, then uses those).
As a nice bonus we wouldn't need to worry about helium or xenon supplies. Just bottle what comes off and let it sit a few years to stop cooking.
Am I a thorium nut? Probably - but the current crop of nukes are all flawed and most of them are inherently dangerous designs which shouldn't have been let out of the lab, let alone used on Submarines or in commercial applications.
FWIW: The level of radioactives in Fukishima's groundwater is close to or slightly below the background levels in seawater anyway and there are places in europe where you'll receive higher doses than anything around Chernobyl or Fukushima just sitting on a rockpile (Granite is radioactive). Nuclear scaremongering has meant that we're afraid of all that "artificial" radiation, but live in places like Denver and jump in aircraft without giving a second thought to our exposure levels. (as an aside, there have been _no_ radiation attributable germ cell mutations discovered at Hiroshima or Nagasaki despite intensive studies since 1946 and the cancer rate in both is 1% higher than background levels. There _are_ mutations and cancer rates well above the norm in places like Love Canal or Minamata Bay (or downwind of oil/coal/gas burning plants)
Given the chemcial processes (and waste) which go into making solar PV, I suspect the antinuke environmentalist faction are barking up the wrong trees. when they raise those bogeymen.
FWIW2: radiation exposure isn't cumulative. As with CO2 emissions, problems occur when the damage rate exceeds the repair rate, which means there's a threshold of exposure below which it simply doesn't matter, and even after a largish dose, as long as healing processes are allowed to do their thing, exposure can resume. If radiation was as dangerous as the scaremongers make out, the average expectancy of airline pilots and cabin crew would be 40-50.
As a resident of said country (and a rider) I believe it's dangerous and will _only_ do it when traffic is stopped and only at low speed.
As someone else pointed out, the vast majority of riders who lane split in moving traffic are on crotch rockets - as are the vast majority of stupid riders(*). Relying on acceleration to get you out of trouble is fine until you run out of road, but it's better to anticipate and avoid trouble in the first place.
(*) I prefer to refer to them as organ donors.
WRT "pulling out" and other "driver didn't see motorcycle" stuff - speaking from a rider's point of view in most cases the rider bears a degree of culpability by loitering in a driver's blind spot, following too closely or failing to "read" driver intention.
There are old riders, bold riders, but not many old, bold riders.
It releases more radioactivity each year in the form of radium (alone) than several chernobyls. There are a bunch of other nasties in there and as others have mentioned a bunch of heavy metals, etc.
Most of the elevated mercury levels in the world's oceans over the last 150 years is from coal burning, as a f'instance, not chemical releases.
We're very good at ignoring what we can't see but is dangerous and demonising stuff with low risk that has high impact (the fear of flying thing - you're more likely to die in a car crash on the way to the airport than to be injured in an aircraft)
"I'm not so worried about low-level nuclear waste, but high-level nuclear waste is deadly for many multiples of human recorded history into the future. "
Please stop drinking the koolaid.
Contrary to popular belief, plutonium and uranium aren't particularly radioactive unless you put a lot of the pure stuff in a small enough space for the atoms to start affecting each other and give them a bit of assistance by arranging things "just right". The greater danger is chemical - they're both highly reactive and highly carcinogenic heavy metals (depleted uranium shells are decidely _non_ radioactive. They kill tank crews more by incineration than by kinetic energy, once they get through the armour and that chemical toxicity means they will leave a nasty legacy where used for decades to come)
"spent" fuel rods are blazingly radioactive thanks to high levels of calcium, cobalt and other unstable isotopes (handling one will kill you from the gamma exposure in very short order)
However: stick 'em in a safe place for 300-400 years and that gamma emission level will have dropped to a level low enough that the rods are safe to handle without requiring special kit - and once the contents are chemically processed, they can be reused as reactor fuel (enough plutonium in them to offset the near-natural uranium balance.
If you don't want to wait that long, just dump it all into a MSR and things will be "burned down" much more quickly - the big "positive" is that given the thorium cycle's calculated efficiency, you should be able to achieve 97-98% usage of the starting fuel, instead of 1%, so the amount of "hot stuff" coming out the other side is minimal _and_ shortlived. It's better to keep "hot" stuff in the reactor and extract the heat as work than it is to dump them in the bottom of a pool and let it heat the water.
MSRs are really good at producing heat and lousy at producing plutonium (it can be done, but it's a LOT harder than any uranium/water setup), plus they don't need massive cooling (they run much hotter than traditional plants, so thermodynamic efficiency is better), can't burp gasses, melt down or explode (the nuclear side is all unpressurised) - and the lack of water in the nuclear loop means they can't leak thousands of gallons of low-level contaminated water either. That makes them a far "safer" system from actual risk point of view.
The steam turbine side comes with the usual issues of steam plants, but that can be entirely decoupled from the reactor itself (it's entirely possible to use sterling engines or thermocouples too) and any steam explosion is just that - a steam explosion
The fact that you can get hot side temps of 700-1400C means that the heat can be used directly in various industrial processes (eg: at ~1200C, water can be cracked to produce hydrogen, then air + plain old Haber–Bosch methods make ammonia from that and end products range from plastics to fertilizer).
Guard those "waste" piles well. They will be useful in the future.
As with the USA, the problem sites in other countries are predominately military.
There's a coral reef in the mid pacific with several kg of plutonium powder scattered across it. The same location is leaking high-level radionuclides into the water at a depth of a few hundred metres, which are being picked up by currents and are detectable at other islands hundred of km away (volcanic seamounts are basically giant piles of sand)
It would have been safer for the French govt to run its nuke tests in an area with a nice solid deep basalt base - like under the Pyranees, but it was politically expedient to do it in the middle of nowhere and play fast/loose with the health of workers where noone could see and pesky protesters could be kept at bay by sticking a limpet mine on one of their boats in a nearby foreign country.
"Or you do what everyone is actually doing, and using gas peakers in those periods."
At some point in the not-too-distant future those are going to be so heavily regulated and taxed that nuclear will be cheaper.
Bear in mind that even the old BWR plants are throttlable (they run at full power for economic reasons, not technical) and the MSR processes were shown to be highly throttlable (5 minutes or less) before Nixon forced the test rig to be shut down.
Assuming that Thorium MSRs take off (and I think that's a pretty safe assumption given the amount of money China's putting into them), the "waste nuclear fuel" problem won't be around for more than 50 years after they become mainstream power sources and most of the rest of the issue is "hot" but shortlived material with a dangerous lifespan of 2-300 years at most.
There are a number of areas with similar background radiation levels to Chernobyl and Denver has far higher background ionising radiation levels than Fukushima simply by being at altitude. If ionising radiation was a dangerous as some of the scaremongers insist, the average lifespan of airline pilots and cabin crew would be down in the 40s, not "no different from the general population" (Fallacy #1 is that radiation exposure is cumulative over your lifespan.)
I know what happens to organisations which rely on "power users of excel" - like the hospital which ran its financial systems on it and ended up several million dollars out of kilter.
Spreadsheets are for simple things. If you need a power user to achieve something with them, then you're using that hammer to bang in screws.
3.7kW might seem insane, but if you look closely many of these are only 350-500 "air watts" - the rest is expended pushing air through HEPA filters.
There are better ways of handling things - external machines (house vac systems) which vent outside don't need to be nearly as high powered, nor do systems which vent the exhaust back down to the suction head - and as a nice side effect they don't spray nanoparticles into the air which invariably end up being inhaled.
Recirculating air in vacuum cleaners might seem logical, but EU and US patents for it (concept and implementation) was only issued in the last 15 years - and the early USA patents are not aimed at improving efficiency of cleaning or reducing power consumption.
Partly it's down to amps - the heating effect of current is the same no matter what the supply voltage might be, but if you're pushing 120V, you need ~twice the current for the same power as you do with 230V (and at 120V the wiring losses are more cirtical than at 230V as a percentage of total available power.)
The choices are to keep the current rating the same, or fit fatter wiring - which costs more.
The other part is that american wiring standards - to be blunt - are dangerously lax, with attendant higher risk of wiring fires (electrocution risk doesn't come into it - it only takes 150mA to kill someone. Fuses are to protect against fires). As such, insurance companies are more paranoid and mandate separate circuits for high power devices.
Slashdot Mirror
gnome is a UI, not a distro.
I'm using multimonitor XFCE and enjoying it.
More circuits == more copper, no matter how thin the wiring is. It's also substantially more labour cost to install, test and maintain.
When you double the voltage to 230V, you can get _four times_ the power from the same resistance - and voltage losses aren't as critical (20V drop on a 230 circuit is no big deal, but it's a big problem on 110V)
110V is annoying to work with because it has so many restrictions. It's no safer than 230V and coupled with more lax wiring regulations you have a much higher rate of electrocutions in the USA than in the EU.
FWIW, the wiring in your "high power" circuits is much heavier than is used in most european circuits - the standard for most outlet circuits is 2.5mm^2, with 4mm^2 being used on long runs or 32A circuits.
Cases can't stay open forever and a declaratory judgement is straightforward.
The UK has the same rules - must have a passenger license and must have insurance.
Uber complied with those rules and would do in Germany too. This is anticompetitive behaviour and will get slapped down by the EU.
"Thorium nuclear generated electricity is even more expensive due to the reactor design needing to be more robust."
Pardon?
Thorium LFTR cycles don't run at high pressure and aren't subject to high pressure water/steam corrosion.
Flouride corrosion is an issue, but it's easier to mitigate than water (Water's not called the universal solvent for nothing)
http://info.ornl.gov/sites/pub...
"By cladding an ASME Type III structural alloy (Alloy 617 or Alloy 800H) with a corrosion resistant layer (perhaps Hastelloy-N modified with 1.5% Niobium) you can provide the high temperature strength and corrosion resistance that advanced high performance LFTRs will require."
That problem has been solved for decades.
The USA nuclear industry keeps going with old designs for the most part because
1: that's all they're allowed to go with.
2: There haven't been any new nuclear plants online to speak of since TMI (none of the "new builds" are online yet and those were almost all started over 30 years ago in any case. TMI effectively put a halt to any unfinished systems, midbuild)
3: Accountants don't like R&D. They'd far rather run with something that works but is dangerous than something which is "untested" but is a lot safer.
4: LTFRs don't produce much weapons-grade plutonium (way down on conventional plants), which the US govt didn't like because it means the "waste" can't be mined for bombs - this is why the USA shut down LFTR research in 1972
Since the 1970s, All the R&D for alternative commercial designs has occurred in other parts of the world. Tinkering with water/steam pressure isn't new technology, nor is setting things up so that the the reactors can passively SCRAM. It's just better engineering. The fact remains that pressurised reactor systems are intrinsically dangerous, as are sodium cooled plants. Lead based systems work but are still based on fuel rods and have proven fairly unreliable in service.
The only serious issue with LFTRs has turned out to be long-term (30 year) storage of cold salts and only because nobody bothered removing the "hot stuff" when the test program finished in 1969. Once the issue was realised and the radioactives extracted, the salts have been stable and no longer require periodic melting/flowing to extract gas buildups.
"Consider the situation of mining REEs in the USA. There is no shortage of them here, but the mines were all closed due to price depression"
The price depression was because US miners had to deal with toxic extraction byproducts and ensure a mildly radioactive material wasn't allowed to enter the biosphere, whilst chinese producers didn't have to worry about the environment.
Now the chinese miners do have to worry, with tougher environmental protection rules being enacted and enforfced.
That radioactive substance? Thorium.
There is enough thorium _already_ mined and sitting in mine tailings to meet current world power demands for a few decades, if not centuries.
Given that it takes 250 tonnes of mined uranium (1% U235) to produce 143 tonnes of fuel grade uranium (3% U235) and the end result is 142 tonnes of nuclear waste, the thought of mining 1 tonne of thorium, to go straight into the fuel cycle and the end product is ~15kg of nuclear waste (yes really) to get the same amount of electricity out (probably more as LFTRs run hotter, which translates to better thermodynamic efficiency) with a system which is intrinisicaly safe on the nuclear side (no steam explosions, metal fires or meltdowns), It's no wonder thorium is attractive. That it can burn down uranium plant "nuclear waste" is an added bonus (a thorium plant needs U233 or other source to get started, but once running it transmutes thorium to plutonium and U233, then uses those).
As a nice bonus we wouldn't need to worry about helium or xenon supplies. Just bottle what comes off and let it sit a few years to stop cooking.
Am I a thorium nut? Probably - but the current crop of nukes are all flawed and most of them are inherently dangerous designs which shouldn't have been let out of the lab, let alone used on Submarines or in commercial applications.
FWIW: The level of radioactives in Fukishima's groundwater is close to or slightly below the background levels in seawater anyway and there are places in europe where you'll receive higher doses than anything around Chernobyl or Fukushima just sitting on a rockpile (Granite is radioactive). Nuclear scaremongering has meant that we're afraid of all that "artificial" radiation, but live in places like Denver and jump in aircraft without giving a second thought to our exposure levels. (as an aside, there have been _no_ radiation attributable germ cell mutations discovered at Hiroshima or Nagasaki despite intensive studies since 1946 and the cancer rate in both is 1% higher than background levels. There _are_ mutations and cancer rates well above the norm in places like Love Canal or Minamata Bay (or downwind of oil/coal/gas burning plants)
Given the chemcial processes (and waste) which go into making solar PV, I suspect the antinuke environmentalist faction are barking up the wrong trees. when they raise those bogeymen.
FWIW2: radiation exposure isn't cumulative. As with CO2 emissions, problems occur when the damage rate exceeds the repair rate, which means there's a threshold of exposure below which it simply doesn't matter, and even after a largish dose, as long as healing processes are allowed to do their thing, exposure can resume. If radiation was as dangerous as the scaremongers make out, the average expectancy of airline pilots and cabin crew would be 40-50.
As a resident of said country (and a rider) I believe it's dangerous and will _only_ do it when traffic is stopped and only at low speed.
As someone else pointed out, the vast majority of riders who lane split in moving traffic are on crotch rockets - as are the vast majority of stupid riders(*). Relying on acceleration to get you out of trouble is fine until you run out of road, but it's better to anticipate and avoid trouble in the first place.
(*) I prefer to refer to them as organ donors.
WRT "pulling out" and other "driver didn't see motorcycle" stuff - speaking from a rider's point of view in most cases the rider bears a degree of culpability by loitering in a driver's blind spot, following too closely or failing to "read" driver intention.
There are old riders, bold riders, but not many old, bold riders.
Many more people die in stolen cars that are being driven recklessly, or from police apprehension, than as a result of remote shutoff
In any case, lojack has been killing ignition in stolen cars for years and there hasn't been a big fuss made.
The software worked perfectly. This is a case of misprogrammed destination ("What do you mean this is Auckland? I wanted OAKLAND!")
"They still sell tape drives? "
"they" do - and this old geezer uses 'em. It's a pity that they're so expensive though (tapes are cheap, drives, not so much)
Tapes have far better long-term storage characteristics than disks.
not that I'd bother if I had less than 100Tb to backup/archive.
I'm surprised they're not pushing sshd low speed versions of these, given the claims that they work better than 7200rpm versions.
It releases more radioactivity each year in the form of radium (alone) than several chernobyls. There are a bunch of other nasties in there and as others have mentioned a bunch of heavy metals, etc.
Most of the elevated mercury levels in the world's oceans over the last 150 years is from coal burning, as a f'instance, not chemical releases.
We're very good at ignoring what we can't see but is dangerous and demonising stuff with low risk that has high impact (the fear of flying thing - you're more likely to die in a car crash on the way to the airport than to be injured in an aircraft)
"I'm not so worried about low-level nuclear waste, but high-level nuclear waste is deadly for many multiples of human recorded history into the future. "
Please stop drinking the koolaid.
Contrary to popular belief, plutonium and uranium aren't particularly radioactive unless you put a lot of the pure stuff in a small enough space for the atoms to start affecting each other and give them a bit of assistance by arranging things "just right". The greater danger is chemical - they're both highly reactive and highly carcinogenic heavy metals (depleted uranium shells are decidely _non_ radioactive. They kill tank crews more by incineration than by kinetic energy, once they get through the armour and that chemical toxicity means they will leave a nasty legacy where used for decades to come)
"spent" fuel rods are blazingly radioactive thanks to high levels of calcium, cobalt and other unstable isotopes (handling one will kill you from the gamma exposure in very short order)
However: stick 'em in a safe place for 300-400 years and that gamma emission level will have dropped to a level low enough that the rods are safe to handle without requiring special kit - and once the contents are chemically processed, they can be reused as reactor fuel (enough plutonium in them to offset the near-natural uranium balance.
If you don't want to wait that long, just dump it all into a MSR and things will be "burned down" much more quickly - the big "positive" is that given the thorium cycle's calculated efficiency, you should be able to achieve 97-98% usage of the starting fuel, instead of 1%, so the amount of "hot stuff" coming out the other side is minimal _and_ shortlived. It's better to keep "hot" stuff in the reactor and extract the heat as work than it is to dump them in the bottom of a pool and let it heat the water.
MSRs are really good at producing heat and lousy at producing plutonium (it can be done, but it's a LOT harder than any uranium/water setup), plus they don't need massive cooling (they run much hotter than traditional plants, so thermodynamic efficiency is better), can't burp gasses, melt down or explode (the nuclear side is all unpressurised) - and the lack of water in the nuclear loop means they can't leak thousands of gallons of low-level contaminated water either. That makes them a far "safer" system from actual risk point of view.
http://en.wikipedia.org/wiki/M...
The steam turbine side comes with the usual issues of steam plants, but that can be entirely decoupled from the reactor itself (it's entirely possible to use sterling engines or thermocouples too) and any steam explosion is just that - a steam explosion
The fact that you can get hot side temps of 700-1400C means that the heat can be used directly in various industrial processes (eg: at ~1200C, water can be cracked to produce hydrogen, then air + plain old Haber–Bosch methods make ammonia from that and end products range from plastics to fertilizer).
Guard those "waste" piles well. They will be useful in the future.
As with the USA, the problem sites in other countries are predominately military.
There's a coral reef in the mid pacific with several kg of plutonium powder scattered across it. The same location is leaking high-level radionuclides into the water at a depth of a few hundred metres, which are being picked up by currents and are detectable at other islands hundred of km away (volcanic seamounts are basically giant piles of sand)
It would have been safer for the French govt to run its nuke tests in an area with a nice solid deep basalt base - like under the Pyranees, but it was politically expedient to do it in the middle of nowhere and play fast/loose with the health of workers where noone could see and pesky protesters could be kept at bay by sticking a limpet mine on one of their boats in a nearby foreign country.
"Or you do what everyone is actually doing, and using gas peakers in those periods."
At some point in the not-too-distant future those are going to be so heavily regulated and taxed that nuclear will be cheaper.
Bear in mind that even the old BWR plants are throttlable (they run at full power for economic reasons, not technical) and the MSR processes were shown to be highly throttlable (5 minutes or less) before Nixon forced the test rig to be shut down.
Assuming that Thorium MSRs take off (and I think that's a pretty safe assumption given the amount of money China's putting into them), the "waste nuclear fuel" problem won't be around for more than 50 years after they become mainstream power sources and most of the rest of the issue is "hot" but shortlived material with a dangerous lifespan of 2-300 years at most.
There are a number of areas with similar background radiation levels to Chernobyl and Denver has far higher background ionising radiation levels than Fukushima simply by being at altitude. If ionising radiation was a dangerous as some of the scaremongers insist, the average lifespan of airline pilots and cabin crew would be down in the 40s, not "no different from the general population" (Fallacy #1 is that radiation exposure is cumulative over your lifespan.)
"Cops would have to release the entire video to the media, and the lawyers wouldn't let that happen."
FOIA
Blocking release would get extremely messy and federal.
"and especially so for power users of Excel"
I know what happens to organisations which rely on "power users of excel" - like the hospital which ran its financial systems on it and ended up several million dollars out of kilter.
Spreadsheets are for simple things. If you need a power user to achieve something with them, then you're using that hammer to bang in screws.
Have you ever tried to work with business-class documents using Word?
Just for shits and giggles: Save your file as a doc (or docx if you insist, but you'll need to gunzip it before proceeding to the next step)
rename the saved file from .DOC to .TXT
Reopen the file and be amazed at the crapola in there.
Just because word is ubiquitous doesn't mean it's _good_.
Speaking as a long-time GUI hater, I find Libre a lot easier to work with than MS Office
It appears the content in question ranged from 50 to 26 years old - the oldest is out of copyright in any case.
3.7kW might seem insane, but if you look closely many of these are only 350-500 "air watts" - the rest is expended pushing air through HEPA filters.
There are better ways of handling things - external machines (house vac systems) which vent outside don't need to be nearly as high powered, nor do systems which vent the exhaust back down to the suction head - and as a nice side effect they don't spray nanoparticles into the air which invariably end up being inhaled.
Recirculating air in vacuum cleaners might seem logical, but EU and US patents for it (concept and implementation) was only issued in the last 15 years - and the early USA patents are not aimed at improving efficiency of cleaning or reducing power consumption.
http://www.g0cwt.co.uk/arc/ is worth a look
"Consumers want number(s) to base their decisions upon"
They do in the EU - "air watts"
http://www.g0cwt.co.uk/arc/new...
Patents issued in 2009 - manufacturer interest, nearly zero.
Partly it's down to amps - the heating effect of current is the same no matter what the supply voltage might be, but if you're pushing 120V, you need ~twice the current for the same power as you do with 230V (and at 120V the wiring losses are more cirtical than at 230V as a percentage of total available power.)
The choices are to keep the current rating the same, or fit fatter wiring - which costs more.
The other part is that american wiring standards - to be blunt - are dangerously lax, with attendant higher risk of wiring fires (electrocution risk doesn't come into it - it only takes 150mA to kill someone. Fuses are to protect against fires). As such, insurance companies are more paranoid and mandate separate circuits for high power devices.
Hard drives are unreliable.
Tapes hold more and are longer lived. I'm surprised FB is bothering with BR.
"A quick on-line search show a spindle of fifty 50GB Blu-Ray discs (2.5 TB) retails for about $100."
You're overpaying. I can buy them for less than 50c each.
DVDs are down under 10c apiece if you look around.
Both are good quality items, not nasty unreliable crap.