Read the original article again. OLD plants emit as much as 10% - new plants with advanced scrubbers emit no more than 1%. Here's the quote, emphasis mine - search for it:
"Some 99% of flyash is typically retained in a modern power station (90% in some older ones)."
That's not my statistic - if you don't believe it, follow the footnotes in the article.
As for the 50 mg/Nm^3, your limit is higher than ours if the 18.3 mg/Nm^3 is correct. The US burned 850x10^6 tonnes (850x10^9 kg) of coal in the year 2009. Even of we go with the 1% figure nationwide, that's still 11x10^3 kg of uranium and 27x10^3 kg of thorium up the stack. Refer to the quote from the same document, below:
"In the USA, 850 million tonnes of coal was used in 2009 for electricity production. With an average content of 1.3 ppm uranium and 3.2 ppm thorium, US coal-fired electricity generation in that year gave rise to 1100 tonnes of uranium and 2700 tonnes of thorium in coal ash."
This article seems to show that Germany is not so clean after all given the relatively large amount of coal it burns compared to its EU neighbors.
This chart shows Germany using 256 million short tons of coal in 2011. That's 232x10^9 kg. With German coal containing up to 13 ppm of uranium and up to approximately 39 ppm thorium (see the first liked article for the source of those figures), that means:
In 2011 German power plants emitted up to 30x10^3 kg of uranium (232x10^9 x 13ppm x 1%) and up to 90.5x10^3 kg of thorium (232x10^9 kg x 39ppm x 1%).
Note that US coal contains up to 4 ppm uranium while German coal contains up to 13 ppm. From the first article, "US, Australian, Indian and UK coals contain up to about 4 ppm uranium, those in Germany up to 13 ppm ...".
I really can't make it any clearer that ALL coal plants emit fly ash, and because of the vast amounts of coal burnt around the world, that fly ash represents a significant and easily detectable amount of radioactivity (not to mention the chemical toxicity) released into the atmosphere around the plants.
I think I've proven my point with reason and numbers to back it up - all you've contributed is disbelief and scorn.