at the number 3 reactor of the fukushima plant plutonium is an ingredient in mixed oxide fuel, or mox fuel. plutonium can remain in human lungs and other organs and cause long-term damage, including cancer. radioactivity from plutonium can be blocked by a sheet of paper. >>> at the troubled fukushima daiichi nuclear power plant the effort to cool the reactors is faced with the challenge of preventing further leakage of highly radioactive substances. >> translator: the challenge is to inject enough water into the reactors for them to cool down stably. but at the same time avoid the outflow of water. >> a tepco official says they have detected on sunday more than 1,000 millisieverts per hour from the water in the trench of the number 2 reactor building. the trench is a concrete tunnel located outside the turbine building near the reactor. it houses power cables and pipes connecting the reactor unit and goes out near the pacific ocean. japan's independent nuclear safety agency, or rather commission, believes that highly radioactive substances found in the trench may have come from the ve

and japan does use mox in its reactors.ocesses the spent fuel and then recycle that plutonium. the united states does not reprocess its fuel, although i am not quite sure of the status, but we have been taking some weapons-grade plutonium and making it into mox. i'm not sure if we have any reactors operating on it. of that reactor, 6% of the corps is plutonium. so the question is, when you put more plutonium in the core, are there more health risks? i would say the answer is probably yes. there is some plutonium any way in spent fuel because the uranium chance mutates into plutonium. so the 6% is much higher than what you would have a uranium- only fuel. i have seen some estimates that suggest that the health risks would be much greater. it is hard to quantify that. i think the union of concerned scientists has done some work on that. we have not focused very much on that in the united states because as a rule we do not use mox fuel. but i think that that is something we are going to have to -- the japanese will have to loo

box we like to call it pox rather than the mox but it is in fact plutonium oxide and if this start it has a lower melting temperature for one thing but if it goes certainly we should be having monitoring stations along california of sodium is the most toxic substance on earth one single atom of plutonium in your body can theoretically cause cancer. i remember years ago talking to john kaufman. in the early seventy's i knew one of my hero yes he was a brilliant man and he said. plutonium is properly distributed which would be almost impossible to kill every human on earth well unfortunately there's more than one ounce of plutonium in fukushima daiichi three this is this since chills up my back right now because we're talking about something a tug of war between the the courageous tepco workers no question tokyo electric power that's a very courageous workers on site are now dead men walking but they are struggling in a tug of war with armageddon right now and i just wonder how many of them are going to end up like many other workers and sure it will go on you know a month or two just d

completely exposed and are made up of a particularly harmful combination of uranium and plutonium called mox. >> it's very toxic. if you inhale plutonium or ingest it, it goes down into the body and it is the most powerful emitter of radioactivity inside the body. >> reporter: there are similar spheres about the spent fuel rods at reactor four. today the white house tried to down play an apparent dispute with its japanese counterpart about how close the situation is to catastrophe. >> president obama has great faith in the idea that the japanese are fully aware of the severity of the crisis. >> reporter: but it's clear that so much is riding on the workers who remain at the plant, now more than 300, it's believed they can only work in shifts of minutes at a time because of the high levels of radiation. they wear cumbersome protective gear and must rely on flashlights in a hot, almost pitch-black plant. one former fukushima worker who wished to remain anonymous told japanese television he's gravely concerned for those he was forced to leave behind. >> i'm still in fear far from the plant afte

would say that the explosion of the reactor number three today that reactor uses a fuel referred to as mox fuel which has been twenty minutes so the dangers from releases from that reactor are higher than the dangerous if there are similar releases from the number one of the number two reactors but another thing i would say is that as there was the first explosion and second explosion and now you know quite likely a thirty explosion each time this happens even if the core of the reactors are not damaged specifically some radioactivity is spread in the region right there at the plants making any further work to bring this situation under control much more difficult for workers whose exposures are high and so are we have to be rotated in and out so each each of these steps is making it harder and harder to control well again this is the spike lee's last the government keeps saying that the safety levels are five there is no risk to your health understandably there are concerns that they may be playing it down to avoid mass panic but in your opinion are they really telling the whole truth to

this is reactor number three is particularly troubling because reactor number three has the so-called mox fuel which is a mixed plutonium and uranium fuel so this fuel is much more intentionally radioactive when it enters the environment than the fuel from the other plants with a legal down a little. now international experts we're hearing are saying the amount of radiation in fukushima is nearing half of that the term noble disaster what do you think the real scale of the catastrophe is that japan is facing at the moment. i think it's catastrophic i think that the narrative that we've had for the last week or so which is that we're trying to fix the problem and get it under control is misleading i think that there's evidence of radiation having entered the environment in large amounts it's turning up in lots of cases in water and food it's even being detected far away in the food it must have been there are present and we could go if it's already turning up and no clients so one of the what this could mean is that there is really a significant entry of radiation going on into the environ

study of the ability of these plants to withstand an earthquake, and also, one of directors uses the mox fuel. >> in regard to the u.s. power plants, they are designed to high standards for earthquake effects. all our plants are designed to withstand significant natural phenomenon. we have a very solid structure in place. we always do. we will continue to take new information and see if there are changes we need to make with our program. with regard to the fuel, we are providing assistance to the japanese where the request our assistance and at this time, they have not asked for specific information with regard to the mox fuel. >> where are the differences between safety in what japan has and the u.s.? >> our focus is on keeping the nuclear power plant in this country secure. we are putting out a strong focus in providing technical expertise to the japanese as the requested. questions about the differences and what changes we might want to consider and look at our something we will deal with down the road. we believe that the planets in this country continue to be designed -- the planets

not just radiation, but so-called mox fuel, a combination of uranium and plutonium. that will likely force an expanded evacuation zone as the government warned that people sheltered inside their homes in this rarely seen place, 20 to 30 kilometers from the plant, are being prepared to evacuate. it is just the latest bad news in what is becoming a more severe radiation emergency than previously known. so, will you test the water every day to make sure it's safe for people? since we have found radiation in the water every morning, we will take samples, as this water treatment plant director from chiba, about an hour east from tokyo. radiation has been found in his water and at similar plants at several other cities. all reporting radioactive iodine, unsafe for infants in their tap water. this woman says she won't use the tap water in her home, even if the government says it's okay. no. it's not just the tap water. a new survey of 8 locations spread over 40 miles of ocean, shows dangerous levels of iodine-131 and cesium-137. there will be a press conference here in a co

at least one of the reactors uses that mox fuel. is there more concerned about that? >> with regard to the u.s. power plants, they are designed to high standards for earthquake affects. all our plants are designed to withstand significant natural phenomenon like earthquakes and tsunamis. we have a strong regulatory structure in place right now but as we always do we will continue to see if there are changes we need to make with our program. with regard to the fuel, we are providing assistance to the japanese. they have not asked for specific information. >> you just talk about how there are high standards domestically. what are the differences between what japan has and what the u.s. has? >> our focus is always on keeping the nuclear power plants secure. we are providing technical expertise to the japanese as they request it. this is something we will deal with them the road but we believe that the plants continue to be designed to a high standard for tsunami events. >> [inaudible] there are already calls for moratoriums in the u.s.. does the president know about thes