Even if we do manage to reduce our energy consumption, closing the nuclear plant would still be more harmful to the environment because we could have closed fossil fuel plants instead
At some point you have to acknowledge nuclear power (particularly from planes dating back to the 60s/70s) as their own waste problem.
And you can try to address this waste with more modern clean up techniques. Or you can decommission these old plants. But just waiting for derelict facilities to crumble, on the ground that “Nuclear Good / FF Bad” means another generation of Fukushima like events that drive people further from nuclear as a long term solution.