MGC wrote:I read that only the #4 reactor was shutdown at the time of the quake...so, the other 3 reactors were at operational temperature. A retired sailor at work who happens to have been a reactor operator on subs told me that it takes a long time for the reactor to cool even with coolant flow. Without coolant flow the heat will continue to build in the reactor core even if the reactor had been SCRAMed. Fission continues all the time and a small amount of heat is generated over time until it reaches the melting point. I use to live right down the road from Waterford 3 nuke plant in Louisiana and read up on the worst case which was a core meltdown which will eventually melt the primary containment vessel, the concrete base and into the earth. Why will this not happen in this case?....MGC
Reactors 1-3 were running, but shut down as designed immediately when the quake occurred. Of course power went down on the grid, but coolant pumps ran as designed for nearly an hour before the tsunami hit and swamped the generators. After that the batteries kicked in and coolant pumps ran for another 8 hours until the batteries ran out. That is when the temperatures started to rise. In other words, the cores were not undergoing fission when they started to melt down. This limits the ultimate temperature that the cores can reach, and it also limits the types of radiation that will leak into the environment. What made Chernobyl so bad was that the cores were undergoing fission when the explosions and meltdown occurred, releasing gamma radiation into the environment as well as massive quantities of fission products which are generally more dangerous than uranium or plutonium fuel. The material is also much hotter when undergoing fission than when it's not, though it will heat up even when not undergoing fission.
In a nutshell this disaster is worse than Three Mile Island, but has absolutely no chance of even approaching the kind of damage done in the Chernobyl incident, which itself was only catastrophic in the immediate region, though there was measurable radiation released all over the world. As I noted above, there are different levels and types of radiation, and effects and severity of release are not all the same.