Of course, the biggest difference between this and Chernobyl is that the Chernobyl reactor was built using carbon to slow down the excess neutrons not water as is used in the ones here.
Originally Posted by pjorourke
But what we do have in Japan is mixed oxide fuel containing plutonium. That wasn't an issue at either TMI or Chernobyl and it raises significantly greater difficulties in this situation.
Depending on how long it's been since those reactors were fueled, there's going to be significant quantities of Pu-239, Pu-240, PU-241 and even some heavier plutonium isotopes in that fuel. That stuff is significantly nastier than the uranium fuel we use. It's far more radioactive than uranium and requires constant cooling even after the reactor is shut down. If it's been a while since refueling there's going to be a decent amount of Pu-241 in there that will really make things a bitch.
Sadly, the crisis will be going on for months. Given the presence of plutonium in the fuel the cleanup is going to take ten to fifteen years and be significantly more complicated and costly than TMI.
Cheers,
Mazo.