I should point out here that, volume for volume, gold is a more effective radiation shield than lead. So, we have that going for us.
unfortunately I don't think will fare as well for him. Very few live through nuclear holocausts. I for one, wouldn't want to.
There are containers rated to protect against nuclear blasts. They will also work in case of a fire in your house.
Heck when there is a nuclear war. I am taking all my coins and stuffing them inside the warhead of the "Atomic Cannon !" I just love to go duck hunting with this thing. http://www.youtube.com/watch?v=goMNAxFqGbk
I'm not sure that putting your coins into a safety deposit box can help. You better off putting them into a faradays box inside a bunker.
If you think that is funny, see FEMA's website. They are very serious about saving yourself and your possessions. http://www.ready.gov/nuclear-blast
Irradiated silver only becomes radioactive for a brief time, but I believe irradiated gold forms an a long lived radioactive isotope that would be hazardous for a LONG time.
Yes central Nevada might work. Maybe make it a exhibit here......http://www.nationalatomictestingmuseum.org/