As workers at the Fukushima Daiichi power plant scrambled to prevent a meltdown of cores of several reactors on Tuesday, a new problem emerged: the failure of cooling systems for several pools containing spent fuel rods. Late Tuesday, Japan’s nuclear watchdog said that the water meant to cool spent fuel in three reactors was becoming dangerously hot. If the water evaporates and the rods become dry, they could overheat and catch fire, potentially spreading radioactive materials in dangerous clouds. To understand the danger posed by spent fuels, Ecocentric has put together a fact sheet with the help of Dr. Ferenc Dalnoki-Veress, a Research Scientist at the James Martin Center for Nonproliferation Studies (CNS) at the Monterey Institute of International Studies. What is spent fuel? Spent fuel are fuel assemblies that have been used in the nuclear reactor to produce electricity and are no longer useful. Spent fuel is taken out of the reactor and replaced by new fuel. Nuclear power plants do this periodically—in some cases, every year.  Once they are removed, however, spent nuclear fuel is very “hot and dirty”–it’s physically hot, but it also emits lots of nasty radiation. So you have to cool it in a special pool for 5 to 10 years to let the radioactivity fade. So what could go wrong? If you don’t keep circulating the water in the pool, it won’t provide enough cooling. It will start boiling. When that happens, steam is released that is radioactive. That makes it very dangerous for workers to approach the pool and fix the problem. Some reports from Japan suggests that might be the current situation. At a press conference on Tuesday covered by the New York Times, a spokesman from the plant’s operator Tokyo Power Company said that “The only ideas we have right now are using a helicopter to spray water from above, or inject water from below. We believe action must be taken by tomorrow or the day after.” What could happen if cooling fails? If you don’t cool the spent fuel, the … Continue reading A New Threat in Japan: Radioactive Spent Fuel