Fuel rod removal: Fukushima’s most dangerous operation yields first successes

[Sirveri]

79. Right, due to U-238 activation via neutron flux you'll have Pu-239

This is the real problem is that there was never any postings as to scientifically why MOX would be worse. Thinking logically there would be more Pu, which has a shorter half life, so you have an increase alpha emission rate. SF neutron flux would be similar since U238 is E-5 while Pu is E-10, and by volume you'll have dramatically more 238 than Pu239 or U235 since LEU is only up to 5%. I suppose they could have been arguing the toxicity of heavy metal poisoning from Plutonium, which is likely accurate, however the same holds true for Uranium and we have studies about the health effects of depleted uranium that at least support concerns about that subject from a heavy metal perspective.

They might have been concerned about airborne uptake of Plutonium due to the differences in half life which would cause an increase in curie count per particle. U235 = 704000000 year half life compared to Pu239 of 24110, so you would in theory get a greater neutron flux and alpha emission rate off of Plutonium, though it's still much lower than traditional nuclides of concern like radio cesium, strontium, and cobalt. Obviously I haven't done the math in this post to see the exact variance in rates. I compared U235 to Pu239 since those are the fertile fuels and the significant difference by volume. Probably still well under limits, don't feel like doing the math right now.