Moving forward, the question of nuclear waste becomes far less of a concern than it was in the past. One of the principal benefits of Gen IV reactors is the ability to consume nuclear waste products as fuel. I could talk about the relatively low volume of waste generated to date, but none of that really matters: the ability to reprocess fuel (on-site no less) to such an extent makes the point--if not effectively mute--then at least even less of a concern than it is today. Coincidentally, it also presents a solution to some of the issues with scaling long-term geological storage. Not just by limiting future waste, but also by actively reducing current waste.
It's too easy for people to reject nuclear energy based on an impossible standard that's applied nowhere else. No fuel source, even renewables once you start to consider the storage question, is "perfectly" safe. Everything, from wind to nuclear to the coal currently being burned, can only be considered in terms of risk. You weight those risks by a matter of degree. Coal sucks, for instance. Not just for the miners, who see significant increases in health risks such as cancer as a result of their work, but also for the communities near coal-burning plants that have to deal with released fly ash and the resulting radiation up to 100x that released from a nuclear plant generating the same amount of energy [1]. And that's not even taking into the account the very real and defined global implications.
Take your airplane example, for instance. Can you quantify it? Not really, given how insignificant the risk for such an event. Reasonable precautions, certainly. But putting the breaks on nuclear energy out of concern for potential destruction-by-airplane scenarios is no different than doing so for fear of potential destruction by asteroid strike. You're right that engineering is always weighing things through a cost/benefit analysis. That's the point, and it's not just limited to nuclear energy. But we need to be intellectually honest and hold different energy sources to the same standard when doing so, not cherry-picking at will.
In the linked article, I saw a few glaring problems. First, we're talking about decades-old reactor implementations (old BWRs, for which embrittlement is of less concern). Second, to date, there's no empirical evidence to support the concern that existing monitoring techniques are insufficient for monitoring embrittlement over time. If you're curious about reading about what issues have occurred (and have been caught), see [2].
I also have some large misgivings over Kropp's willingness to make a comparison to Chernobyl that has no basis in fact. Even if his nightmare scenario were to play out exactly as described, you wouldn't get a Chernobyl event. The RBMK reactor's flaws were well-known even during early design stages, but a number of factors converged in the accident (lack of training, over-classification that kept critical information from workers, disabled/limited safety mechanisms, corners that were cut in construction, lots and lots of graphite, etc.). Plus, you know, no containment vessel (!).
Quite frankly, you couldn't build a reactor like Chernobyl's in the United States (or even the western world more broadly). Even going so far as to imagine a scenario where some fiendish element wanted to purposely recreate the disaster here, they couldn't do it. So when people start drawing comparisons to Chernobyl, and use it to influence modern risk analyses, they're highlighting their own political biases and scientific ignorance. I don't think you were making this mistake, but some of the comments in that article certainly were.
Debating the subject is good. But we really do need to make sure that we're actually debating the options themselves, rather than skewed representations of one. That sort of flawed reasoning only serves to hamper us in the long-run. Given our energy requirements, current global trends, and the long-term environmental concerns, nuclear represents the only commercially viable energy source capable of solving our problems. We naturally want to do so safely, but there's a difference between risk management and risk aversion that amounts to sticking one's head in the sand. It's far, far too easy for the debate to shift towards the latter.
[1] http://www.scientificamerican.com/article/coal-ash-is-more-r...
[2] http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/pr...
[3] http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Power-R...