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'30 Year Laptop Battery' is Unscientific Myth
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."
Meh. It's a beta emitter; beta radiation is completely harmless to humans as long as you have a nice layer of skin between you and it.
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.
ad logicam Claiming a proposition is false because it was presented as the conclusion of a fallacious argument.
The power demands are wildly different between a fricking SUB and a fricking LAPTOP. The power generation is also far different; subs have active fission piles, they're literally mobile nuke reactors.
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) have been used in the space program forever.
ad logicam Claiming a proposition is false because it was presented as the conclusion of a fallacious argument.
It's not significant really. The amount of tritium in this, even concentrated, is pretty low, and would make a really poor weapon...On the order of throwing florescent bulbs at someone to try to poison them with Mercury vapor. It also disperses pretty quickly, so the lasting effect is minimal in the area.
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).
ad logicam Claiming a proposition is false because it was presented as the conclusion of a fallacious argument.
Defense contractors are always coming up with wonderful sounding ideas that are completely impractical. For example, in 1999 a company called Stavatti presented the DoD a design for a portable laser rifle suitable for use by common infantry. The device was to be powered by...wait for it... polonium (PO-210). An excerpt from the proposal:
.75 kg in a rifle that would be subject to damage, destruction and dispersal on the battlefield.
"...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
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.
How is this "bringing more problems"? Businesses have used fluorescent lighting for years. You're only hearing about this issue now because it's a change in peoples' homes. When was the last time you saw people in such a panic about mercury thermometers or thermostats? Yet they contain *hundreds* of times more mercury than a standard CFL with its 5 *milligrams* of mercury. And the amount of mercury is dropping; Phillips is down to 2 milligrams. Even going with 5mg, a CFL releases less mercury even if you were to take after it died, smash it, and aerosolize all of its contents, than if you used a normal incandescent for that time; A coal plant will release 10-15mg of mercury over the lifespan of an incandescent, and only 2.5-4 for the CFL. Coal produces over half of our electricity. And we're only talking about mercury here. As for all other pollutants, CFLs are way, way ahead because of their lower energy consumption. And this all assumes that all of the mercury from a CFL ends up in the environment.
You really have to take an extremely biased view for CFLs to come out worse than incandescents.
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