Re: It is an engeneering problem not a nuclear problem.
No, it is not an engineering problem. It is a social / economic problem.
The calculations were made to harden the plant against a massive tsunami but the accounting department deemed the chances too low to that actually happening so the height of the protective wall to be build was lowered with all the current problems as a result.
IMO the problem is greed. Companies like TEPCO are only out to make as big a profit as possible. You can do this by upping prices (see how electricity became cheaper per the prediction of the pro nuclear lobby from the 60's - so cheap we don't have to meter it) and by reducing costs. Safety features are expensive so the bare minimum is implemented. Maintenance and actual repairing faults is also expensive so it is easier to bribe the inspector. the lifespan of reactors is being extended until they fail or the government will shut them down. This may all sound horrible and irresponsible but from a business perspective this makes perfect sense and that is why it is happening.
As long as we will have greed I don't think nuclear power is safe. And running it by a not for profit outfit will not work either because there is too much power (the influence power, not the electric power kind) involved and people will get corrupted.
The only way to run a nuclear plant is build by engineers, run by engineers, managed by engineers without restriction on budget to have the safest plant available. This will never happen.
And then we did not even start talking about the mining of the fuel and the disposal of the waste.
If we could move society to another reward system than money / power maybe then we could have safe nuclear power.
My nut case proposal would be to ban all commercials and tax all companies to the exact amount that they spend on marketing and use that money to fund independent scientific research. Preferably from the blue sky kind.