Why be depressed - these things have been targeted for years by both foreign and domestic terrorists. Outside the US, in fact, attacks on oil and fuel pipelines are pretty common, especially in the Middle East.
The biggest mistake the US made after 9/11 was the government doing things to make it look like they were doing something. They required a major increase in nuclear plant security - they were already the most secure industrial facilities we had. Meanwhile, they ignored the more likely and more dangerous targets like chemical and petro plants, which had NO federal security requirements (they do now).
Wanna really disrupt the nation - how about blacking out the entire east coast? We’ve been through it a couple of times so we know what it’s like. Yet nothing has been done to really protect the electrical distribution system (including a single spot in the northeast at which you could black out about half the country!). Don’t even ask me about water treatment plants - most of which are unmanned for most of the day.
But the biggest mistake we make is worrying about what WE think are good terrorist targets. There are hundreds of nuclear plants around the world, some in some very unstable countries. None has ever been the target of a terrorist attack. On the other hand, how many malls and grocery stores have been attacked in the last 10 years, the last 5 years, heck - the last 5 days!
After 9/11 people around where I live were all worried about the two nuclear plants where I worked. But they had no problem going to the Monday night football game at the most storied NFL stadium in the country the week after the attacks. Now, which do you think is a better terrorist target? Attack a nuclear plant and probably get killed before I get past the fence - or bomb a football stadium and kill 80,000 people.
My point - if you’re going to spend all that time worrying, at least spend the time worrying about the right thing!