There's no strong deterrent there. These plants don't blow up like nukes, or even Chernobyl. Nuclear disasters require very precise conditions to sustain the chain reaction. Blowing up a reactor with conventional weapons will spread the fuel around, which is a nasty pollution, but localized enough that it's the victim's problem not the aggressor’s problem.

Why do you even mention transformers and cables as an implied alternative to nuclear power plants? Power plants absolutely require power distribution infrastructure, which is vulnerable to attacks.

From the perspective of resiliency against military attacks, solar + batteries seem the best - you can have them distributed without any central point of failure, you can move them, and the deployments can be as large or small as you want.

(BTW, this isn't argument against nuclear energy in general. It's safe, and we should build more of it, and build as much solar as we can, too).

I recall hearing in school that 9-11 masterminds had considered planes against nuclear power plants but abandoned it after doing the math and realizing that it would do little damage. Not sure how true that is admittedly.

Reinforced concrete is great if they're just shelling you. Sure, all the outdoor infrastructure will be toast but your reactor probably won't get damaged. It'll take a bit to get back on the grid but you don't need to rebuild the plant.

Bunker busters, on the other hand, eat reinforced concrete for breakfast. A pinpoint strike into each reactor hall and you're down for good.

The former is cheaper, less risky for the attacker, and hurts you bad enough for most military purposes, so the latter isn't really worth worrying about unless you're Iran or North Korea.