One could argue it is necessary but it is undeniable that it is not effective -- nuclear power plants take decades to bring online and then they may never see break-even. Not only that but they require vast sums of water for the entire lifetime of the nuclear plant (which is fast becoming a scarcity, if not because of increased consumption but also because of changing water availability.)
On the other hand, renewable (wind and solar) can be brought up MW by MW, on a much faster timescale, privately funded (all nuclear is publicly funded now), and it has much better unit economics even without subsidies. Renewable energy is here to stay, it is going to become more abundant, and it is going to become more reliable with each passing year.
Nuclear is as unreliable as ever, even after 70 years of modernization, the economics of scale, and unlimited access to the public purse.