The United Nations has declared August 29th to be the International Day Against Nuclear Tests.
There are several specific resources you might be interested in:
The Best Sites For Learning About The Marshall Islands – we have a lot of Marshallese students at our school, and the legacy of nuclear testing in their home is a terrible one. There are a number of resources on that “Best” list that tell that story.
This last one is, unfortunately, outdated: The Best Classroom Resources On The Potential Iran Nuclear Deal