I have a scientific/engineering background, and I don’t understand radioactivity. So, I’m writing up this little thing, summarizing wikipedia entries, etc.
Thanks to the weak nuclear force, splitting atoms = mucho heat. Neutrons spread out from the split atoms, and bust up other atoms that aren’t all that stable to begin with. The whole process starts by putting atoms that “leak” neutrons with a bunch of other similar atoms, and depending on the density of those atoms, you get nuclear reactions suitable for generating the heat which lets us light a city, or reactions which obliterate one.
Extra neutrons floating around, also bad. Leads to cancer, death, and (rarely) glowing in the dark. Check.
Okay, so the extra neutrons flying around all over the place don’t just split other atoms. Sometimes, they incrementally increase the size of an atom, creating plutonium or other elements which stick around for very short periods of time, unlike plutonium.
- Radiation.
- There are three forms of radiation that we get taught about. Alpha, beta, gamma.
- Gamma is high frequency electromagnetic radiation.
- Alpha particles are helium nuclei, and
- beta particles are electrons.
- Gamma rays travel, like light, or radio waves, and are harder to block (lots of lead required). But they also don’t stick around, so they aren’t responsible for the bulk of the danger from radioactive wastes.
- Beta particles are slower, and tend to stick around more (blockable by thin sheets of metal)? (but we have dislocated electrons in batteries around us all the time, so how would this be a major problem?)
- Alpha particles are downright pokey by comparison, and can be blocked with thin sheets of paper. They tend to stick around. But once again, helium is around us all the time. Assuming these highly positive helium nuclei manage to swipe some innocent atoms’ electrons, where’s the problem?
- There are three forms of radiation that we get taught about. Alpha, beta, gamma.
- this is the part I didn’t get:
- Spent fuel rods contain radioactive isotopes of several elements. When uranium splits into other things, the other things stick around. Many of them absorb neutrons, and start radiating (while also inhibiting the reaction of the fissile elements through that absorbtion.) This is why spent fuel rods are dangerous, still contain material that can be reused, and yet will not continue to react.
- Nuclear explosions are a different story. They release vaporized radioactive debris (which turns into nanoscale dust). That debris spreads on the wind through rain, etc. (didn’t read as much on this one, because it wasn’t my main interest).
- A passing exposure to some level of radiation isn’t so bad. It’s ongoing exposure to a source of alpha, beta, or gamma radiation. For instance, radioactive iodine (like non-radioactive idodine) gathers in the thyroid, where its radiation destroys tissue in the area and increases the risk of cancer.
So much to know…
blah blah blah blah…. *g*
s’ok! I love ya anyways! its kinda sexy when you get excited about tech stuff!
Not that it answers any questions for you, but I thought I’d share a little tidbit of information passed on to me via one of our x-ray technicians here on the burn unit…
Out of curiosity one morning, while assisting with a daily chest x-ray on one of our patients, I asked the technician how many x-rays in a year are deemed safe. She couldn’t really answer that, but told me that when she was in training, they were told that a single chest x-ray emits the equivalent engergy as a flight from Edmonton to Toronto. CRIKEY!!
I might be misreading you, but what that means is you absorb as much radiation as you would on a flight from Edmonton to Toronto, not as much energy as it takes to fly. The point is that people fly all the time and don’t worry about radiation.
Actually, you are misreading me…
She meant the energy expended in a single chest x-ray is equal to that required to fly a jetliner from Edmonton to Toronto. It had nothing to do with errant radiation. Whether this is fact or fiction remains up for debate, but she claimed that was taught to her while in school.
I’m not doubting you were told this, but I do bout the veracity of the claim.
Realize that the lion’s share of the cost of a jetliner’s flight is in the energy used to make it go. The cost per passenger for this energy is well over a hundred dollars. The number of passengers is well over a hundred. The total energy costs are thus well over ten thousand dollars.
How much does a chest x-ray cost?
Err, doubt, not bout.
What k8to said. I think the technician misunderstood what she was taught, because I’ve heard this comparison (my version) before.
A single x-ray ups your cancer risk. It significantly ups the risk for breast cancer later in life for girls under 20 given multiple chest x-rays, for a random example.
My guess is that a CAT scan is on average worse, with a PET scan being worse than that.
So far, MRI’s don’t (to our knowledge) have any effect on cancer rates.
I think the issues are all about the energy levels involved. A stationary bullet is not very dangerous.
I think you’re spot on when deducing that it’s the amount of radiation sustained which is the key. A high intensity bombardment can be a problem, but continued contact with lower intensity fields is more likely, via acquiring radioactive material in the body or in the clothing.