Reactors Protectively News Today : Breaking News, Live Updates & Top Stories | Vimarsana

>> reporter: its reactors protectively shut down after the earthquake. than an emergency system pumps in water to cool the facility's fuel rods, but the cooling system failed so did the backup system when the tsunami hit. now operators are using sea water to try to cool the fuel rods and prevent a meltdown. >> it's a very frightening situation. and we can only hope for the best, hope meltdown doesn't occur. >> well, some scientists say the best-case scenario is the situation in japan -- that the situation in japan ends up like three mile island. a partial meltdown occurred and radiation was re...

Data that comes into the center. we have the terrain, land use, the kind of buildings and structures available. we use all that information to basically attempt to estimate the impact that occur downwind from the release point. >> how quickly can you track what it is and where it's going? >> so the models will typically run fast in five to ten minutes, we get a close picture to what occurred on the ground. >> winds over japan have been blowing eastward to the pacific coast. the information from narac is vital to federal officials who would decide whether to move anyone out of the potential dan...

Great personal risk, they're putting their lives on the line, my guess is many of them will pay the ultimate price. and they're doing it because they care about their country and because someone has to stay. you know, the other issue here is that each day we sort of discover a new problem. and here's the new problem. if you have multiple reactors next to each other and you need to be working on three or four or reactors to try to keep them from melting down and you have a big problem at one of them, then you're going to have to send the workers away, but who is left to continue to manage the p...

Reactors. that's a high number. much higher than it should be. and another important fact, which is up to 175 miles away on the uss george washington, they were detecting low levels of radiation. so imagine radiation gets released as it starts to disperse, the amount of radiation, the levels are going to start to go down. walking around a country like the united states, for example, you're subjected to about 3 millicevers a year. 400 at any given time right next to the reactor. what that means for people outside the gates tens of kilometers away. still unclear. but you can -- it's a relatively...

Health." exactly what that means is still unclear. glenn shadeen joins us via skype from texas to break down all of this for us. good morning, glenn. >> good morning. >> how did this go from a situation where they felt they were going to get a handle on this, find some productive backup system to continue to cool to what we're talking about today, which is the leak of at least some amount of radiation from one of these reactors? >> well, i've got to tell you, things have dramatically changed in the last several days. initially, you know, they were recording just slightly elevated radiation lev...