Thanks for posting such an interesting article, radiation is such a terrifying, damaging and invisible thing. Debate is now raging about the safety of nuclear energy in light of recent disasters.
Miso is a very healthy choice for most people, however if there is a history of thyroid problems in your family tree, or indeed you have a diagnosed thyroid condition, you may wish to check with your health care professional before embarking on a Miso rich diet. Here is a link to a site which seems to have some sensible advice regarding soy and your thyroid.
http://thyroid.about.com/od/soy/a/soy-thyroid.htm