joining us this morning. thank you. american troops are being warned about low levels of radiation. the uss george washington at a naval base 200 miles south of the fukushima daiichi plant says it has detected radio activity. they stress no danger to the public people at the base are asked to limit outdoor activities. ouch our dr. sanjay gupta is live in japan. it shows you the deep concern spreading across this country. reporter: yeah. no question that, you know, if you take all of these things in aggregate, all of the information you ve been hearing, that this is not a good thing overall. you re adding more radiation to the population over there. you talk about this 200 miles away, 175 miles away radiation making it that far at very low levels. you need to put it in context,
there s some suggestion now, jim, that these reactors in japan, they re in level six. somewhere between three mile island and chernobyl. is that what you re hearing as well? i have heard that. i heard a french engineer offer that had assessment. in some ways you can unction it. in chernobyl you had the outright release of large amounts of radio activity because there was no containment vessel. and you had a steam explosion and a fire that carried that directly into the environment. that has not happened yet. we are not at that point. we seem to a be a little worse. this is shocking for people here. we re in a worse position than three mile island. yes, there was ha meltdown. but most of that radioactivity was contained. the containment vessel held. now we re somewhere in between that. we are worried about the containment vessel at reactor number 2. there s worries of possible damage. and then we have the fire and
line site. worse than that is the chance the fuel will catch fire. it s hot and it can cumbust. the way this reactor is designed, mark one reactors, they don t have a container around the spent fuel pole. it s a real concern. the fire could liberate as much radio activity or even more than the accidents that are occurring at unit one, two and three. let s come back to that point. six units in distress. three of them the issue is spent fuel rods which are not protected. not inside a secure containment shell. if you have one where you have a fire and two others with this issue, number one you assessed
sets of nuclear material that we have to worry about. the nuclear material inside the reactors and the nuclear waste material which is in the cooling pool. this fire is in the cooling pool which you said already is not inside the containment structure which can deal with pressure and with shielding radiation. so the fear if this fire continues and continues to spew up a cloud of steam, that steam will contain particulate matter of items like eye iodine and these are materials which are highly radioactive. and so will be a continuing source of radio activity once they are deposited away from the site. and they will be contaminated the land around it the one thing to look for if they cannot get this fire under control by getting water on it, is to see
what your biggest concerns right now as they try to stem this before more radioactive material leaks? really two issues here. the first is, how much radio activity is going to leak out of these four plants? and, of course, we don t know the answer to that as yet. the other big part of the story is the wind. the wind is absolutely crucial here. by and large the wind is blowing offshore, meaning that the activity is going to be blowing in towards the ocean, which is a good thing. how long does it take that to disperse? let s say it does go in the right direction, flows away from population centers. how long before that cloud is not dangerous to humans? well, that depends on how long the source is there, how long the radio activity is being remitted to the reactors. once that stops, within a few days the main part of the cloud will dissipate. there s normal we get radio we re exposed to radiation all the time. that s right.