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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."
the article is correct that radiation destroys semiconductor efficiency although not all "nuclear battery" designs involve semiconductors. space probes sometimes use a chunk of radioactive material that has shielding around it while the energy released is in the form of heat. this heat [temperature gradient] is harnessed by a thermoelectric materal- basically it consists of several layers of different metals that produce a voltage potential in response to a temperature gradient. the advantage in this is that you can use metal as shielding and not relatively fragile semiconductor material. although you need a radioisotope that can generate enough heat from decay to be useful- tritium's half-life is about 12 years so it might qualify, although a better solution might be a solid unless they use T2O, ditritium monoxide, which is "superheavy water"
Sigs are too short to say anything truly profound so read the above post instead.
When an old scientist says something is possible, he is probably right. When an old scientist says something is impossible he is probably wrong. (I'll let you ponder the seeming paradox, but you'd have to know some old scientists to really get it.)
We already have "dirty" nuclear materials in the hands of consumers: some types of smoke detectors, lead paint detectors, x-ray machines, and some other things.
If someone wanted to make a dirty bomb, a few thousand dollars worth of the right smoke detectors would do perfectly.
The betavoltaic battery is nothing more than pseudoscience. It's higher quality pseudoscience than junk such as zero-point free energy generators or gravity wheel generators, but it is pseudoscience nonetheless. Every few years you see these sorts of claims about betavoltaic devices pop up again, then fade away.
Despite years of claims, no one has ever come close to demonstrating a device with the sort of power densities claimed in the article. Furthermore, the biggest proponent of betavoltaic technology is Ruggero Santilli, an infamous pseudoscientist with a litany of nutty claims and bizarre theories of physics.
If you look at the web pages of the companies that are involved in betavoltaics (e.g. betavoltaic.com or nuclearsolutions.com), you'll find that they have no physical facilities outside of a rented post office box or the home of one of the principals. None of them have any product to sell or even demo. I don't expect that will ever change.
Bremsstrahlung x-ray radiation is a problem working around high-energy beta emitting radioisotopes, such as Phosphorus-32, but not Tritium, which is a very low energy beta emitter. Betavoltaics are real, workable technology; not science fiction or junk science. Cardiac pacemakers using Plutonium-238 Radioisotope Thermoelectric Generators are also a proven, decades old technology, too, for example. Tritium is an extremely low energy beta emitter. Given this, and the very short biological half-life of water in the body, it is one of the least harmful radioisotopes around. It occurs to a very small degree in nature, and is already used in radioluminescent watches, exit signs, gunsights, keyrings, compasses and such forth. The beta emission from Tritium is so low in energy that most radiation detection instruments will not detect it - only mixing the radioactive material with the scintillation cocktail in a liquid scintillation counter is sensitive enough to detect it. A gamma spectrometer, scintillation counter, geiger counter, ion chamber counter or detector won't even notice it.
Kinda impractical to stuff your laptop with several million gallons of radioactive waste.