The biggest source of concern in the aftermath of the massive earthquake and tsunami in Japan are three of the country's nuclear power plants which were damaged in the quake and may be leaking radiation. Scientists are unsure how extensive the damage is or will be, but the world is keeping a close eye on whether the reactors can be shut down safely. People living near the nuclear power plants have been evacuated and tested for radiation, an invisible form of energy that can make people very sick or, in very high doses, even kill them. NewsHour Science Correspondent Miles O'Brien says the biggest risk of a nuclear power plant leaking significant radiation comes from the radioactive core of the reactor which can melt down and leak out of its container. So far, the world has had two nuclear power plant accidents of varying scale: the Three Mile Island accident in Pennsylvania, and the Chernobyl disaster in Russia. Chernobyl was much worse because it involved a fire and total meltdown of the radioactive core, while Three Mile Island did not result in any deaths and leaked a comparatively minimal amount of radiation. Currently, scientists are comparing the situation in Japan to Three Mile Island rather than Chernobyl and hope things will stay that way. Note: The first four minutes of this video is a discussion with NewsHour Science Correspondent Miles O'Brien about how a nuclear reactor works and the risks it poses. The rest is a discussion about the specific situation in Japan. Quotes "Whatever the case may be, in theory, it becomes so hot, that it would melt its way out of this primary containment chamber. We haven't seen that yet, but this is still a very tense time. They're pouring in seawater into these vessels, as best they can, to keep it cool. Now, that means they have written off these plants. You will never be able to use them again." - NewsHour Science Correspondent Miles O’Brien "If the incident was to stop right now, the amount of radioactive releases is really very small. And the risk to the general population, just like it was in Three Mile Island, would be very small indeed." - David Brenner, Columbia University Warm Up Questions 1. What kinds of sources does the world get energy from? Which are most common in the U.S.? 2. What is nuclear power? What are its risks? 3. What is radiation? Discussion Questions 1. Do you think we should continue to use nuclear fuel to generate electricity, or is it too risky? Why? 2. According to the video, what are the Japanese using sea water for in their nuclear reactors? Will they ever be able to use those reactors again? 3. How do you think the safety of nuclear power compares to the safety of other forms of energy, such as oil, coal and wind power? What are the advantages and drawbacks of each form of energy? Additional Resources Video Transcript Nuclear Waste in Yucca Mountain Download this Video