konnichiwa. we say hello to the mother and children. the children are still smiling but we learned that being here has sheltered the mother from the bad news. when you hear about the explosions -- we tell her of yet another explosion, her face goes blank, stunned but safe tonight along with 200,000 evacuees and counting. the japanese government has distributed more than 200,000 iodine tablets meant to help stave off any effects of radiation. initially thought to be just a precaution, but now they're dealing with this third explosion at a nuclear plant. and tonight as our crew here moves west to get further away from those plants we carry with us these small sensors that detect any changes in the air and so far our grid has not changed so that, of course, is a propsing sign here. i'm david muir for "nightline" in japan. >> they have widened the evacuation area to 20 miles around he wants everybody to stay indoors. our thanks to david muir and when we come back, we will take you to the one place that had all of our crew in tears today rig