Naked Science Forum
Non Life Sciences => Technology => Topic started by: McKay on 02/07/2014 22:07:39
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Radium and nuclear power has bad reputation but it has great potential non the less.
Radium was, as far as i know, most famously used in glowing watch hands mixed with fluorescent paint and the mixture was not covered with nothing much but glass so light can pass trough, right?
AS I have red, the radiation itself is not very intense from such a small source and that is not why they ware banned. It poses a much greater risk when flakes break of the watch hands and get inhaled or something like that..
So, to reduce direct radiation from the watch (or whatever) and reduce the risk of of radium getting in to the environment or the body, have the radium sealed in a lead or, perhaps, tungsten or something else, durable and dense. .. hmm, that makes it pretty safe, right? But also not really useful. Perhaps electric current be extracted - as radium will produce positive alpha particles and leave a negative radium atom, electrons will flow to gain back the equilibrium.
Probably not much electric current can be generated that way and most of the energy will be lost as heat, which we cant convert with high efficiency, specially at such low levels..
Is there really nothing currently doable to make safe nuclear batteries ?
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Many workers in radium factories eventually died of leukemia or other cancers. So the danger is very real.
Today Tritium is sometimes used to illuminate watch faces. At least it has a short lifetime (a decade or so), and if released will tend to rise up in the atmosphere, away from humans.
The most practical source of nuclear power is the Thermo-electric generator, used in space probes.
Plutonium oxide is chemically fairly stable - provided it doesn't get powdered and inhaled.
See: http://en.wikipedia.org/wiki/Thermoelectric_generator
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Although Plutonium oxide thermal power generators are very reliable the plutonium is exceedingly expensive and there is a worldwide shortage to the extent that research is ongoing to use Stirling engines that have a higher conversion efficiency and can produce the same power using less Plutonium.
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Radium is hazardous because of its short half life and high output, and because its chemical similarity to calcium that makes it aborbed by biological systems, and because its production of other radioactive elements, particularly radon gas. A good encapsulation scheme could minimize two of these hazards (calcium similarity and gas output). But it also suffers from another drawback: scarcity. However, the latter problem can be minimized by using the radium as efficiently as possible. A scheme for doing so may be as follows: Since radium decays by alpha emission, and alpha particles are charged, they potentially could form the basis of an electric circuit without intermediary processes such as thermoelectricity or steam turbines. Probably the most straightforward way to do this is to have the radium decay in the center of a hollow conducting sphere which exists at a much higher electrical potential than the radium. As the alpha particles are released, they would do work against the electric field, adding their energy to the field while at the same time slowing to much safer speeds, ideally reaching the sphere at a speed near zero. One problem with this, of course, is that the energy involved is several million electron volts, requiring an equally large voltage between the radium and the sphere for ideal operation. That may be possible in a large, unwieldy installation, but not in a flashlight.
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We use a lot of dangerous, hazardous chemicals that should not get released in nature or get in contact with most living things. Many of which have smaller benefit than nuclear power could have.
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I'd go with Evan on the use of Tritium.
You can shield its with a piece of clear plastic... perhaps even cellophane wrap. Not only does it decay rather quickly, but its decay products are also non-hazardous.
When you look at Radium's decay chain, it is a fairly long chain including a radioactive gas. And, even the final product, lead, is moderately toxic.
Personally I think you're better with chemiluminescence or Phosphorescence if you wish to create a low energy dull glow.