That said, I'll bet the first taker a dollar against a doughnut that 90% of U.S. nuke plants sail right through into the new millenium and don't even trip for any technical reason. (I won't bet against *political* reasons.)
Why do I think so?
Nuke plants are much less computerized than you might think.
Many still use electromechanical relays to provide important logic functions. Relays have a lot going for them - for instance you never have to worry about introduction of stupid software bugs.
What about real bugs introducing themselves into relays? :) A few years ago a nuke plant wanted to build a computerized control system and USNRC absolutely gave them hell, requiring them to document every damn line of it and prove that it could handle all special cases. But they did finally approve it.