Quote:
Originally Posted by Peter Knutsen
But how many rads would it give off per time unit?
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That's a fairly meaningless question, because the units aren't compatible, but trying to answer this in a sensible way, U-238 has a half-life of 1.4e+17s, meaning the portion decaying every second is roughly 5e-18. Decay energy is 4.27 MeV, but it rapidly (days) undergoes beta decay (270 keV), and then again (minutes) under goes beta decay (2.27 MeV) into U-234, which is generally it on the short term, so the total is 6.81 MeV of radiation. 6.81 MeV/238amu = 2.7e12J/kg, so total is 1.4e-5W/kg. One gram of ingested uranium would thus be 1.4e-8W; for a 70 kg 'GURPS normal' that works out to 2e-8 rads/sec, or 0.63 rads/year. Natural uranium chemically separated from ore will contain U-235 and (stable daughter) U-234 (plus any contaminants which didn't get removed chemically), making it several times as radioactive.