Deighton is a master of the flawed, well-meaning or even heroic character leading into tragedy, because the universe doesn't work the way you'd want it to, and your "good" qualities are as likely as your flaws to cause your downfall.
Those RBMK reactors had inherent limitations and Soviet safety culture was rather cavalier, so honestly, averting Chernobyl probably just delays a major nuclear accident in the territory of the USSR, and little more.
Another question might be: what if Chernobyl had been worse? Serhii Plokhy makes mention of how there were fears that all the fuel in the reactor(s) would melt down, causing an extinction-level event from the radioactive spread. I don't recall if the amounts at the time could have led to such, but a greater/wider impact than OTL is certainly possible.
I also think there could be interesting implications of such an accident in a post-Soviet state.
I think that the potential for "Europe glows in the dark"-level catastrophe was just an urban legend, but I'm sure that if more material had leaked and the wind had gone the wrong way, Kyiv might have been seriously damaged, say.
Possible necro-post, but the idea just occurred, so I felt like sharing:
The only other existing or planned RBMK plant outside of Russia proper besides Chernobyl itself was in northeast Lithuania.
Well, that's the thing- the fronts described in Book 1 all move quite a bit more than their European equivalents (the Confederates get pushed back to Maryland from Pennsylvania in the first year of campaigning) and they make it quite clear that they are very different from the areas still able to have a war of maneuver out west (we don't directly see warfare in Texas, but we know Lubbock fell in 1915, we see Kansas evolve from daring cavalry raids and irregular warfare to something much more conventional settling in on the Ozarks before those viewpoint characters die). They don't necessarily have a war by inches to compare it to, but it is a more mobile war than OTL's in Europe.
Mostly going from memory too, but I thought that the static warfare made sense east of the Appalachians (i.e. Virginia and Maryland), and possibly in southern Ontario if there was no naval supremacy, but not in other locations such as Kentucky. Kentucky had far too many miles and not enough people under arms to be the equivalent of the Western Front. It would have made more sense to be more like the Eastern Front, which still had the logistical issues but was more mobile, than the trench lines which seemed to stretch across Kentucky - though those trench lines may have been in Books 2 or 3, I don't remember for sure if they were in Book 1.
