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"Also, the shorter half-life means higher energy radiation, which furtheri.e.
increases the danger."
This is certainly true for Alpha decay, but I don't think so for gammas,
the energy of the excited state of a daughter is not easily related to theand a
half life of the parent, yes?
For Betas, I estimate the six order change in 1/2 life results in ~ 40 X
increase in end point energy (assuming similar matrix elements). In both
cases "so what": A sheet of paper will stop the most energetic Alphas,
few inches of concrete the Betas.species
bc who has measured (lab exercise) the specific activity of a nuclear
(K-40) to determine its half lifeor
P.s. Radioactive fallout intensity is ~ T^-1.2 from ~ten min. to 200 days
a reduction in activity of 4* E-6; after that it is more rapid. This is a1*E-9 is
result of the varying half lives of > 200 isotopes of 36 elements. (The
gasses krypton and xenon are not included.) A further reduction to
reached in 25 years. This is a drop in the bucket considering the twoounces
of fission products per kiloton yield is, in gamma activity, equivalent toisotopes
30,00 TONS of radium in equilibrium with its daughters!!!! (Remember one
milligram of radium has an activity of one milliCi.) As the shorter
decay the rate will approach exponential decay. quick calc.: initial 2oz.
(2.7E10 Ci) in 25 years is 270 Ci or 4.8 Ci / initial gram of fissionU -- ~
products. The power station's waste will additionally include depleted
10E9 yr. half life? (source: Glasstone, 'The Effects of NuclearWeapons"
1962)mass
Tim Folkerts wrote:
BTW, why are we so much more worried about shipping spent rods than
fresh ones, which are being shipped all the time with no apparent
controversy. There may be a good explanation for this. I just don't
know one.
I was wondering about this too, but then had an idea. Presumably the
has a& volume are similar before and after use. However, the uranium fuel
equal1/2 life of ~10^9 years, while the waste is ~10^3 yr. This means an
half-lifeamount of material is 10^6 more radioactive. Also, the shorter
means higher energy radiation, which further increases the danger.
Tim Folkerts
Department of Physics
Fort Hays State University
Hays, KS 67601
785-628-4501