mariana is a research associate with harvard university's project on managing the atom. she joins me now from cambridge, massachusetts. well, things seems to be thankfully more under control now. but more broadly, what are the risks with an incident like this? >> well, michael, russian shelling of a nuclear power plant was an extremely reckless behavior. but actually, it takes several things to go wrong at the same time to precipitate a serious nuclear accident at a nuclear power plant. these are facilities that have very robust safety and security measures in place, especially since, you know, the chernobyl nuclear power plant accident and the fukushima nuclear power plant accident, all of these protocols are getting updated constantly. but several -- if we have several things that go wrong at