Ratio of radiation sources in the uranium cycle Sorry, I know y'all are probably getting a lot of questions re: Fukushima, but I had a very specific one and no-one has been able to answer it.
I am specialised in medical radiation, and have been explaining the risks to workers in this accident, but I need to know what are the rough proportions of alpha, beta (+/-) and gamma radiation flying around.
If I have this right, most of the decays in the uranium cycle are alpha or beta+ and beta-. Some isomeric transitions (and obviously the beta+ decays) will release gammas. Obviously there will be a small amount of xrays too, from Bremsstrahlungs and such.
But what are the percentages of this in general uranium fuel material (I guess 'spent' fuel is the real problem here, not fuel undergoing chain reaction)? Is 50% of the radiation alphas? Is 80% gammas?
It makes a huge difference from a biophysics perspective as alphas are easy to protect against (for the workers) but gammas are unshieldable. Beta- decays are in between, pretty easy to deal with.
Anyone know the uranium fuel cycle well enough to give a rough estimate here? 
EDIT: Added some thoughts in my response to Bars, who helped a lot. Any other thoughts that follow on from those insights?
 A: *

*Te-132 - beta 

*I-132 - gamma 

*I-131 - betta & gamma 

*Zr-95 & Nb-95 - beta

*Ba-140 & La-140 - beta



That's from wikipedia & http://www.matpack.de/Info/Nuclear/Nuclids/
A: The thing you have to worry about most (unless you're close to Fukushima) is not the radiation by the reactor itself but the radioactive isotopes of Cs and Iodine, which when consumed expose body cells to direct and no longer shieldable radiation. That's why Iodine pills are distributed (I'm not a doctor, but one shouldn't take some unless instructed to) to saturate the Thyroid so the radioactive particles don't stay. 
A: It is impossible for anyone here to tell you that with any degree of certainty.
What's emitted depends completely on the state of the system. What materials are contained in it, and at what relative concentrations for example.
How it's shielded (the shielding itself will get excited and emit both particles and X-rays).
The main danger from any radiological incident like this isn't the direct radiation at all (unless you're in the direct vicinity) but fallout from radioactive products dispersed through the atmosphere.
We can likely expect for example some of that in the form of rain as the water used to cool down the cores evaporates and rains down again later. This will of course be massively diluted depending on distance and time.
At any distance from the source, even gamma radiation will be low enough that it's no threat.
What most laymen never seem to grasp (in no small part no doubt due to scare campaigns designed to do just that) is that radiation at low doses is NOT a problem.
My guess is that the people now panicking in Tokyo (and even the US west coast) aren't getting any more exposure than they'd get during a dental X-ray, at most.
