If they lost all power, and the ability to use hpci/rcic, then they would have blown down the reactor to the suppression pool by now. Assuming they also lost power to containment cooling and sprays, is the only reason I could see them venting to atmosphere.
Since it appears they've lost all power, they are no doubt into the T-200s for venting. The reactor should be 2/3rds covered, at least, and down near 50-150 pounds if they are anything like ours... meaning safe. Decay heat is also much less than 1% by now.
Of course, this is also assuming they have TRIPS similar to ours.
A loss of all offsite power was one of my fortes at Peach Bottom, but admittedly, an earthquake throws a wrench into the works that isn't often covered over in my neck of the woods. However, there would have to be A LOT of things go wrong that would prevent them from keeping the reactor depressurized right now. That is why it is my wager that the reactor is fine, and that containment is their concern. Again though, I don't know what they have in the way of say.. diesel driven fire pumps or back up nitrogen to ADS. The media keeps saying reactor pressure though, which means a lot of thing would have to go wrong. Besides a loss of power, they would have had to lose nitrogen to their ADS valves, which require no power to operate. If there is one thing you should be able to always do at a BWR, its blow the reactor down to the suppression feature. So not knowing exactly what they have/don't have, or that what the media is saying is accurate, there really is no way to tell. I am just trying to think about what I'd be doing if I was back at Peach Bottom and this happened.
One thing I do know is that I would love to be in their control room right now.
