From a quick google, the krypton was vented on purpose over the course of weeks, to keep radiation at safe levels. Government regulators were involved. All of

From a quick google, the krypton was vented on purpose over the course of weeks, to keep radiation at safe levels. Government regulators were involved. All of us are immersed in background radiation all the time. Raising the level slightly, but still within normal background levels, is not a significant safety concern. It's certainly far less concerning than climate change, or even the direct pollution from fossil plants.