This shot has a lot of potential. The way you used the sun for a dramatic affect is quite good. If only you had been able to be in a position to have it a bit more obscured by the tower.
There is too much dark foreground. Eiter crop it or use a different angle.
I see where you mentioned you had to be careful not to get caught. I imagine this didn't allow you a lot of time to compose and wait for better conditions.
Still a good image, that maybe you will be able to revisit.
The reason the picture was not framed very well was that there was a code Orange, taking a picture of a atomic power plant with out getting arrested was a trick.
A little less of the sun would be better. Smoke is well lit, The stacks need to be in focus and perhaps closer so they're more of a powerful element in the shot.
A little oddly it does look like the hot spot did not force the aperture closed as the tree on the right is sharp but the horizon seems a little OOF as if the aperture was what you might expect of an evening shot i.e. wide opne with narrow DOF.
Finely captured! Did you plan this one out like this? Amazing colors. I myself would have cropped out more from the bottom and left more sky in the top.
Basically a great idea for a shot, badly let down by the technical work: love the sun through the steam from the cooling towers, but the processing artefacts, the tilt of the image, the strange framing (why so much at the bottom, and why cut off the top of the steam clouds?) lose you points from me.
Is the resemblance to a mushroom cloud intentional, or did it just work out that way? Very nice colors and capture on the setting sun. I really like the rim lighting on the bottom of the cloud.