They have no intention of bombing the plant of course, or doing so in a way that would cause any serious destruction, especially when Putin's clear intentions are to take the entire Ukrainian territory; to me this is just psychological warfare to fuel the fear among other nations about nuclear dangers, so that both leaders and the public opinion will be against going at war with them. In theory, we (as EU) could intervene with traditional weapons so that the burden of escalating it further would still be on them; not an easy decision though.