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Nuclear Battery That Runs 10 Years
Jenny writes "A battery with a lifespan measured in decades is in development at the University of Rochester, as scientists demonstrate a new fabrication method that in its roughest form is already 10 times more efficient than current nuclear batteries -- and has the potential to be nearly 200 times more efficient. Similar to the way solar panels work by catching photons from the sun and turning them into current, the science of betavoltaics uses silicon to capture electrons emitted from a radioactive gas, such as tritium, to form a current. As the electrons strike a special pair of layers called a 'p-n junction,' a current results. I can imagine lots of applications for this new battery including my own laptop."
So now instead of just overheating... my laptop can have a total meltdown?
"Everything you know is wrong. (And stupid.)"
Moderation Totals: Wrong=2, Stupid=3, Total=5.
Before going off and thinking that a radioactive battery would be bad because
of toxic exposure through its mere presense, please read this Wikipedia article about Tritium, which explains
that " The low-energy beta radiation from tritium cannot penetrate human skin, so tritium is only dangerous if inhaled or ingested."
So it might make a good candidate for a household battery.
How does tritium affect people's health?
As with all ionizing radiation, exposure to tritium increases the risk of developing cancer. However, tritium is one of the least dangerous radionuclides because it emits very weak radiation and leaves the body relatively quickly. Since tritium is almost always found as water, it goes directly into soft tissues and organs. The associated dose to these tissues are generally uniform and dependent on the tissues' water content.
How does tritium change in the environment?
Tritium readily forms water when exposed to oxygen. As it undergoes radioactive decay, tritium emits a very weak beta particle and transforms to stable, nonradioactive helium. Tritium has a half-life of 12.3 years.
How do people come in contact with tritium?
People are exposed to small amounts of tritium every day, since it is widely dispersed in the environment and in the food chain. People who live near or work in federal weapons facilities or nuclear fuel cycle facilities may have increased exposure. People working in research laboratories may also come in contact with tritium.
How does tritium get into the body?
Tritium primarily enters the body when people swallow tritiated water. People may also inhale tritium as a gas in the air, and absorb it through their skin.
What does tritium do once it gets into the body?
Tritium is almost always found as water, or "tritiated" water. Once tritium enters the body, it disperses quickly and is uniformly distributed throughout the body. Tritium is excreted through the urine within a month or so after ingestion. Organically bound tritium (tritium that is incorporated in organic compounds) can remain in the body for a longer period.
Obliteracy: Words with explosions
Betavoltaics? I'll wait until this radioactive battery is more... stable.
Computers are useless. They can only give you answers.
-- Pablo Picasso
A) Have a freshly-maimed lap full of delicious, toxic, viscous, burning battery acid; or
B) Inhale the rough equivalent of breathing a couple months' worth of naturally-occuring tritium?
Take your time. This one's a toughie.
Obliteracy: Words with explosions
p-n junction can be so much more than a diode. A diode is in many cases composed of a single p-n junction, but diode != junction. I totally agree with the poster for calling it that way.
You don't call two p-n junctions in the transistor a diode. You don't call the p-n junction in the solar cell a diode...
The term "diode" can also be applied to a vacuum diode, Schotky diode, etc. neither of which is composed of a p-n junction.
They're probably pretty close to indestructable, so I wouldn't worry too much about idiots. Even if they do manage to penetrate the outer shell, the materials will probably be of a "safer" radioactive type such as an Alpha Emitter. Alpha rays are generally not dangerous as they easily bounce off the outer skin.
The primary safety hazard is actually the inhalation of an Alpha Emitter. Once inside the soft tissues of the lungs, the emitter increases the risk of broken DNA strands, thus leading to cancer. Note that this is a worst case scenario. Most Alpha Emitters are far too heavy to float in the air, and far too strong to be easily pulverized into pieces small enough to float.
Note that evidence suggests that the other concern, indigestion, is a non-issue. In all documented cases where Plutonium (a common alpha emitter) was accidently ingested, it was found to pass through the digestive tract without issue. Radiation was not an issue due to the general thickness of the digestive system.
Compare this to the safety hazards of Alkaline and other battery technologies. These technologies can easily poison water wells, are quite dangerous if ingested, have the potential to explode, and can cause serious burns when in contact with the skin.
Javascript + Nintendo DSi = DSiCade
Consider the following:
You could engineer your batteries to produce significantly more power than the system needs. As the isotope decays, you approach the system's minimum power needs. System alerts you six months before it needs a new battery.
You could design a hybrid battery--part traditional power storage, part nuclear generation. As the traditional battery is drained, the nuclear battery charges it; best of all, when you're not using the laptop, it charges by default. You wouldn't need a nuclear battery big enough to run the whole laptop--just big enough to stretch that five hour standard battery to a ten-hour battery, with the added bonus of automatic, cordless recharging when the system isn't in use...
Obliteracy: Words with explosions
There is no mention of the power delivered by the battery - only its lifetime. It doesn't take much to run a pacemaker, but a laptop might require a battery the size of a loaf of bread, for all we know. Also, while tritium isn't all that dangerous, it IS radioactive, and carries all of the regulatory baggage that goes with that designation, so great care would have to be taken to prevent leakage during its lifetime, which wouldn't be easy.
"Anyone that has ever gotten an idea based on any of my work and done something better with it-good for you."--J.Carmack
Disclaimer: I am a nuclear engineering graduate student.
This seems like a rather nifty extention of the technology. However, note that the fuel source, tritium, is rather hard and expensive to come by. (The total world supply of the stuff is < 40 kg.) So I see this as a great boon for, say, space probes or other fancy applications where getting your hands on some tritium gas aren't the biggest of concerns on the budget. It'd be interesting to see how they compare to other nuclear batteries that rely on heat from alpha-decay of heavy isotopes like plutonium to generate electrical currents.
As far as all the jokes about a nuclear laptop battery using this technology causing sterility, note that tritium decays via beta emission (i.e. an electron), with a range in solid materials of a few mm, so those energetic electrons will stay in the battery. Your primary concern would be if you somehow cracked the thing open and inhaled the tritium gas -- then those few mm of exposure in your lungs etc. aren't the best things to have around energetic particles. (And, as far as having to ingest nuclear sources, tritium is probably one of the better ones, since not only does it have a relatively short half-life of ~12 years, but it gets flushed out of the body rather rapidly as it diffuses into the bloodstream/water in tissues, leading to a much shorter effective biological half-life of 11 days.)
This will be awesome in iPods.
Until your mother launders it.
And you take a screwdriver to it.
And it flips you into orbit.
-- often wrong; never in doubt
Actually, you'd keep the battery and buy a new laptop for it every few years.
f u cn rd ths u cn gt a gd jb n cmptr prgmng
There is another way to make a "nuclear battery", which was discussed in the september 2004 issue of IEEE's Spectrum magazine (could not get a link...): by ionizing a bit of matter, it gets attracted to other matter (think static electricity). So you ionize a flat, piezoelectric part that's attached at one end over an unmovable base plate. The attraction makes the loose end of the part strain down to the base, and the piezoelectric nature of the part makes it generate electricity on the way.
You're not old until regret takes the place of your dreams.
This is going to be an interesting thing to see develop over the next few decades. Nuclear power went from this supposed clean and perfect energy source to becoming the demon of nuclear war, chernobyl and three mile island. When you say nuclear power to people, they get images of three-eyed fish, cancer, etc.
Having said that, safe nuclear power, which is entirely feasible right now, is really our best option for dealing with energy shortages in the near future. The pebble bed nuclear reactor technology doesn't melt down, provides copious energy, and doesn't emit a gram of CO2. Plus, if I'm not mistaken, the disposal of the pebbles is less troublesome than the leftovers from the more traditional reactors.
A nuclear battery that could last 10 years would be way better, not only for the users of the batteries, but also for the environment. Think about how much energy you have to use to charge a laptop. All of that energy is primarily coming from fossil fuels. Then when you are done with the battery, you throw it in a dump (at least most people do), and the heavy metals that go into most of those batteries leak into the environment.
Of course, in order for any of this progress to happen, you're going to have to get people comfy with having a radioactive source a few inches away from their crotch. It might have all the shielding in the world, but it's still going to make a lot of people nervous.
This sig has been temporarily disconnected or is no longer in service
There's a modest demand for tritium. It's needed to recharge H-bombs. Fusion researchers need sizable quantities of it. It's used for night lights in exit signs, watches, and gunsights. Tritium has a half life of about 12 years, so you lose 5.5% every year as it decays to helium-3. So a new product that requires tritium faces a major supply problem.
The hazards of tritium exposure aren't high, but some precautions are required. Cleanup procedures for a broken tritium exit sign are as follows:
When an Exit Sign Containing Tritium (3H) Is Damaged (broken with the release of 3H):
The protective clothing required for cleanup usually consists of gloves and booties. The broken sign should be placed in an air-tight container by a health physics consultant. If silica gel is available it should be placed in the container with the broken sign. The silica gel will collect tritiated water. At a minimum, the broken sign and any miscellaneous pieces should be double bagged and sealed in plastic. Disposal of the broken sign should be arranged through the manufacturer or a health physics consultant.
And people screw up, even with ordinary exit signs. Here's a Nuclear Regulatory Commission report from 2004:
USAF personnel in the Johnston Atoll in the Pacific were attempting to remove the "batteries" from an exit sign they believed to be battery powered. During the attempt to open the case, they destroyed the sign only to discover that it was a tritium sign. All tritium modules were broken.
Five personnel were in the room at the time and all were potentially exposed to the tritium. The Radiation Safety Officer (RSO) isolated the room and the personnel clothing, etc. Pre-cleanup surveys indicated greater than 6 times the normal background survey readings in the room. The RSO double-bagged the sign and tritium module debris. The room and work areas were decontaminated. Post-cleanup surveys indicated normal background readings. Personnel uptake and dose evaluations are currently being assessed.
So, like the nuclear batteries of the 1960s, this will be a specialized technology of very limited application.