[MertsA]

This wasn't a nuclear weapon, it was a poorly contained RTG and from the sound of it the fuel rods weren't even inside the device yet. A good sized hunk of Pu-238 in the glaciers feeding the Ganges is cause for concern to say the least. The half life of Pu-239 like what would be used for a nuclear bomb is 275x times as much so even just the small amount present for the RTG is releasing many many times more fission products and radiation than a sizeable nuclear weapon.

[LorenPechtel]

It doesn't sound like there was a containment breach. Pu-238 is hot, that's why it can be used for a RTG. That doesn't mean it's frying you.

And it doesn't release more radiation than a bomb. Pu-238 is an alpha emitter--and alpha emitters can only hurt you if they get inside your body (or from simple heat--pick up one of those rods and you'll get burnt just like if you picked up any other hot piece of metal.) The decay product is U-234, also an alpha emitter and with a quarter of a million year half life.

Likewise, it's Pu-239 contaminant is an alpha emitter and decays to U-235, likewise an alpha emitter, this time with a half life of three quarters of a billion years.

You also don't understand about half lives--you get one decay per atom. If one isotope has a half life a thousand times as long as another you get one thousandth as many decays per second and thus one thousandth the radioactivity per unit of time.

A bomb converts material with a long half life into material with short half lives and thus greatly increases the amount of radioactivity.

[MertsA]

>It doesn't sound like there was a containment breach.

Trace amounts were detected in the melt water. Plutonium does not exist in nature, all significant amounts are man made. I think it's likely that that plutonium came from the lost RTG fuel rods. The article explicitly mentioned that the American climber was tasked with handling the fuel rods and loading and unloading the device. They lost it at their base camp, not where they intended to deploy it. I believe that would mean that most likely the fuel rods were not yet loaded and sealed into the device and were instead still inside whatever lead lined box they were transported in. I don't know what the actual fuel assembly would have been for a plutonium RTG fuel rod from the 60s but I have a feeling it wouldn't stand up to 60 years worth of corrosion in a wet and warm environment outside of the generator it was supposed to be assembled in.

As for the radiation amount, I meant in the hypothetical scenario of comparing it to a lost but undetonated nuclear weapon which would be substantially less radioactive. I'm well aware of what a half life of an isotope is. The half life of Pu-238 is basically as bad as it gets because at 87.7 years it'll take a substantial amount of time for the radioactivity to subside yet as far as half lifes go that's pretty low and would still be highly radioactive. Pu-238 in a water source is pretty bad and while it might be trace amounts now, if the fuel rods are compromised after all that time they're only going to get worse and start leaching out more and more.