The thing that is unclear in your original comment is exactly what I was mentioning in mine. You didn't write what kind of threshold you were calculating here (which together with the bottom part of the comment made me think it was about actual radiation sickness). Now that you've made clear it's about the EU dosage limits I can easily follow. As I've said, there is a world of difference between where cancer risk begins, and where you can expect acute radiation sickness, and if you'd been calculating the latter there could potentially still be a significant (cancer) risk with much less ridiculous consumption numbers.