It is a mixture of "look what happens if we let everybody have nuclear power: now Pakistan and India have it, and there is a great chance of a nuclear conflict" (simplifying). And at the same time the ecologists, saying "NO to nuclear power" (I remember this in my childhood in Spain, it was huge).
Fuckushima has turned it into what seems a non-negotiable idea at any costs.
But notice that some weeks ago the European Commission decided to push for calling nuclear "green" (I agree with this) but also liquified gas (!!).