'30 Year Laptop Battery' is Unscientific Myth 322
An anonymous reader wrote to mention the wonderful news: "A research group funded by U.S. Air Force Research Laboratory is developing a battery which can provide continuous power to your laptop for 30 years! Betavoltaic power cells are constructed from semiconductors and use radioisotopes as the energy source..." Except, not so much. ZDNet's Mixed Signals blog with Rupert Goodwins explains why (as always) if it sounds too good to be true, it probably is: "The sort of atomic structures that generate power when bombarded with high energy electrons are the sort that tend to fall apart when bombarded with high energy electrons. While solar cells have the same problem, it's to a much lesser extent. There's a lot of research into making materials that don't suffer so much, but it remains a serious issue ... while it's true that a tritium-powered battery will eventually turn into an inert, safe lump of nothing much, and while it's also true that a modest amount of shielding will keep the radioactivity within the the battery the while, there's the small problem that if you break the battery during its life the nasties come out."
Re:Laptop? (Score:5, Informative)
However, when it gets into the body it is EXTREMELY harmful, so the worry is that people will break the batteries open and release toxic crap into the environment where it can be inhaled/ingested.
Sub != Laptop (Score:5, Informative)
Atomic batteries, on the other hand, are just storage for existing nuclear material. They generate electricity as part of the radioactive decay process, either by using the heat generated by the decay, or by harvesting the incident energy of the decay process.
Types of radioisotope batteries (like RTG's [wikipedia.org]) have been used in the space program forever.
Re:What pissed me off on that was this assumption: (Score:3, Informative)
Re:Laptop? (Score:5, Informative)
Tritium is available in the environment already; it's a naturally occurring isotope of hydrogen, and it's half life is pretty low (~12 years).
Re:Laptop? (Score:2, Informative)
Tritium is commonly used in a lot of places. If your wristwatch glows in the dark, it's probably tritium.
Blue-sky defense contractors (Score:5, Informative)
"...To increase the energy level of the CO2 N2 He gas mixture, a Zirconium-Nickel fuel rod approximately 40cm long and 1.8 cm in diameter containing approximately 740 grams (78cc) of Polonium-210 (Po-210) is contained within, and located down the centerline of, the cylindrical gas reservoir. The Po-210 provides a thermal energy source of approximately 141 watts/gram through the emission of alpha particles via the process of nuclear decay. This energy source provides a significant power density while alleviating the shielding requirements and apparent health risks associated with gamma ray emitting radionuclides. The presence of the Po-210 in the reservoir chamber will result in the delivery of approximately 104.34 kW to the CO2 N2 He gas mixture, thereby raising the gas to a state of thermal equilibrium corresponding to an internal reservoir pressure of approximately 272.1 atm, temperature of 2173.16 K and gas density of 44 kg/m3..."
You may recall that a few micrograms of PO-210 were used to kill that guy in London about a year ago, and this company has proposed putting
The paper describing the laser rifle can be found here:
http://209.85.165.104/search?q=cache:SEji6Jn6-4AJ:www.defensereview.com/352003/TIS1.pdf+pumped+polonium+laser+rifle&hl=en&ct=clnk&cd=1&gl=us [209.85.165.104]
It's Tritium (Score:3, Informative)
Voyager didn't use tritium batteries; they wouldn't have been powerful enough, or long lasting enough.
I wouldn't worry more about using this stuff (if it works) than a lithium battery. They both have their dangers. People are so damn paranoid about radiation; this is better than a lot of stuff we expose ourselves to everyday, without a thought.
Re:Laptop? (Score:4, Informative)
On a side note, our first CF bulbs didn't seem to last. They were kept inside of glass fixtures. We got another batch, and new fixtures (the old ones were a fire hazard anyway). These are open fixtures, and so I assume the bulbs stay a lot cooler. We have yet to burn up a single CF, after 3.5 years...and these new ones seem brighter than the old ones. Also, make sure they are not on a dimmer. That can make them die early I believe.
Not that crap again... (Score:5, Informative)
This is another of those hard to die myths that will have to be debunked over and over again. Consider:
a)Butter has a higher energy density than a laptop battery
b)The hydrogen in a cup of water, if fusioned all the way to iron, would release enough energy to flatten a city ( or power it for our entire lifetime).
c)A lithium battery holding 0 charge is just as flamable and dangerous as a fully charged one.
I think this myth came about because people figured nuclear = dangerous, and Li-ion = dangerous. In reality things are far from that simple. It is not the energy density of Li-ion batteries that cause them to explode, as an example, it is the fact that they contain lithium, which is a very reactive alkali metal. As I already mentioned, a completely depleted Li-ion battery could still catch fire, and if you pulverised it and poured water on it, it would literarely explode as the liberated hydrogen ignited.
For a car, you could vitrify an isotope like Plutonium-238, forming a very inert ceramic rod which would produce heat at a perfectly predictable rate. It would also be very safe since even if the ZOMG terrorists tried to use it in a dirty bomb, the inert nature of the ceramic would keep the plutonium contained, and as a pure alpha-emitter enclosed in a ceramic, there would be virtually no mentionable radiation release. To give you an idea of how safe such a device could be. They have been used to power pacemakers.
It would also be absolutely useless for a nuclear weapon, even if the pure Pu-238 could be recovered, since weapons need very pure Pu-239. Just the heat generated from Pu-238 would make a fission weapon virtually impossible, and the neutronic properties make it absolutely useless.
The only reasonable risk I could see from such a device would be if it was left in a very enclosed space so that the heat generated would start a fire. This is however a fairly limited engineering problem which is not unique to RTGs. Similar precautions are needed for electric heaters and engines.
Main disadvantage is the ( at present ) fairly high price of Pu-238. Producing it in quantity is a fairly complex process, and it would probably be a lot cheaper to just use regular battery electric vehicles.
Re:Laptop? (Score:3, Informative)
Re:Laptop? (Score:5, Informative)
You really have to take an extremely biased view for CFLs to come out worse than incandescents.
Re:Laptop? (Score:3, Informative)
Also available is a statement by the EPA on the subject quoted at http://news.nationalgeographic.com/news/2007/05/070518-cfls-bulbs_2.html [nationalgeographic.com]
Finding docs describing coal-fired power plants as the single largest cause of environmental mercury is easy, but going too far beyond that requires more than the 3 minutes of googling I can afford for the subject.
Re:Laptop? (Score:3, Informative)
Still, I must strongly disagree with the author's pessimism. Offhand, I can already think of a system that wouldn't suffer degradation, something like a dusty fission fragment reactor [aiaa.org]. Basically, your "fuel" is a nanoscale powder (say, a tritium polyethylene), which is inherently self-ionizing because of the beta emission. You have them in a core with charged walls, so the particles all distribute themselves roughly equidistant from each other. Since the particles are so small, their individual absorption cross-section is small, so they tend to not thermalize the radiation. You can use magnetic fields to collimate the weak beta into beams and decelerate it in a grid to recover almost all of the energy. Everything except for the magnets is little more than a hollow shell, keeping the weight down.
I haven't done the calculations on what size the device would be, though. That may be a limiting factor in this particular design. Still, I think the article shows a failure of imagination. Just because the current crop isn't up to snuff doesn't mean that all will be.
Re:Laptop? (Score:3, Informative)
You might find the snopes article on the subject [snopes.com] useful.
This guy doesn't know much about nuclear batteries (Score:3, Informative)
The author makes a point of stating "only 25 watts per kilo". Of course, a laptop draws about 10 watts with good power management. So the nuclear battery, according to his stats, would weigh less than a pound. (I suspect however, that a nuclear battery could not be that light, because tritium simply doesn't emit that much energy. For something more radioactive like Am-241 I could believe it. But you'd need a *lot* of tritium to generate 10 watts, and it would be very expensive. Even condensed as tritiated water under pressure, I'm not sure it'd fit into a practical volume, or be cost-effective.)
Further, stating there's a danger of release of radioactivity is just more typically ignorant anti-nuclear FUD. The battery would be likely sealed and constructed in such a way that it would be almost impossible to break. This isn't difficult; my USB flash drive can handle a semi truck driving over it.
Re:Lighthouse batteries (Score:2, Informative)
http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator [wikipedia.org]
http://www.bellona.no/bellona.org/english_import_area/international/russia/navy/northern_fleet/incidents/31767 [bellona.no]
Very clearly not something that would be approved for everyday civilian use!