According to the information from the internet, the extraction and refining process of 157 tons of U 308 for nuclear power plants, leaves 155,000 tons of tailing that still contain 60 to 80 percent of the radioactive uranium. In other words the tailings are radioactive, but not as highly radioactive as the fuel rods that go into the reactors or the very highly radioactive material of the spent fuel rods.
Australia alone exports 10,000 tons of refined uranium per year.
There are about 440 or more nuclear power reactors around the world that produce electricity, plus there are many nuclear reactors that are not classified as generating electrical power, but they, never the less, use nuclear material, which means that they are generating alpha beta and gamma radiation.

Since all these operations happen in the atmosphere and the radiation is spread into the atmosphere, it is no wonder that the background radiation is increasing, and it will not surprise me if the air molecules would leave the atmosphere never to come back again.

Good info on nuclear reactors around the world.

http://en.wikipedia.org/wiki/List_of_nuclear_reactors

http://www.euronuclear.org/info/encyclopedia/n/nuclear-power-plant-world-wide.htm

Effects of iron dust in the ocean.

http://t.news.ca.msn.com/canada/haida-gwaii-ocean-iron-dump-investigation-to-proceed-1

Your smoke detector produces 66.8 MeV energy. That is, for every californium atom that converts to thallium atom.
Uranium atom 238 to lead atom 206 = 51.7 MeV
Uranium atom 235 to lead atom 207 = 46.7 MeV

Remember that 165.2 million electron volts of energy is only THREE ATOMS worth, how many of those atoms are in a kilogram of the stuff that is used in the nuclear reactors, and how many kilograms of that stuff is spread in the global environment.
So; yes I believe that it is possible that such a phenomenon can happen.

Australia started mining uranium in 1955 and now exports more than 10,000 tons per year.
I wonder how many MeV’s have been released from that operation alone and how it has affected the global environment.

What someone else says about nuclear energy.

http://www.opednews.com/articles/Review-of-The-Film-Pandora-by-Ethan-Indigo-Smith-Chernobyl_Death_ENTROPY_Fukushima-140128-887.html?show=votes

Illegal nuclear waste dumping.

http://gizmodo.com/the-mob-is-secretly-dumping-nuclear-waste-across-italy-1513190243

Other stuff.

http://www.world-nuclear-news.org/NN-Swedish-ship-makes-first-shipment-2801144.html

http://www.world-nuclear-news.org/WR_Sea-route-safe-from-strontium-sources-1411137.html

http://www.bing.com/videos/search?q=nuclear+waste+storage&docid=4654036414301824&mid=9295D2DD9D62ADAB40DE9295D2DD9D62ADAB40DE&view=detail&FORM=VIRE4#view=detail&mid=9295D2DD9D62ADAB40DE9295D2DD9D62ADAB40DE

http://www.youtube.com/watch?v=29nUlNardjU&feature=player_embedded

Worth watching.

http://www.youtube.com/watch?v=29nUlNardjU&feature=player_embedded#t=134

a. correcting all this, and:
b. complete obliteration of life,

…either of which would end with a “who really cares?” result.

Atmosphere channeling out to space has been going on forever, but there’s a catch to this in the Earth’s magneto-sheet, which draws the majority back in, and we’re being replenished by both biological and igneous sources.

As for radiation, most of this is underground, and the Western World takes a very dim view of surface and atmospheric nuke detonation testing. After all, it’s a dangerous practice, and just about anything anyone could hope to learn from this can be found more safely, and far less expensively — comparatively free — in the Britannica on-line.

If you want to destroy a planet, all you really have to do is persuade the inhabitants to build more internal combustion engines, sell them to developing nations and drive them more often.

The battery-world isn’t looking too hot, either, but the threat of lithium and mercury contamination is another story.