A radioactive wasteland wouldn't work as a buffer?
Like Hiroshima and Nagasaki? A modern fission-fusion-fission device with tritium in the pit to give additional neutrons to more completely fission the plutonium has more fallout byproducts, but the time-factor is the same, 6 months max if you don't mind third-world health and mortality levels.
But anyway, the worst stuff, because it gives off hot highly penetrating gammas and has a good degree of bioavailability and uptake, the Iodine 131 goes through a half-life in 8 days. Two weeks to a month would be enough time for any military that presumably has a lower standard of safety concerns for it's troops, and for all I know within American/NATO guidelines for ground forces too.
The gold standard in fallout enhanced or "salted" weapons is the "cobalt bomb" which uses the extra neutron rammed into "regular" colbalt-59 to make Cobalt 60. And it has a half-life of 5.something years. Nasty, but not exactly the EOTW scenario either. While it lasts much longer, it's not as "hot" as some of the more traditional fallout products. And again, the area is survivable without any special protection in a decade. The Korean DMZ has stood much longer through political/ideological will from both sides than Cobalt-60 could have accomplished.
And the weight and expense of adding the cobalt to the bomb somewhere caused just way too many downstream engineering headaches for having to rework the missile, the torpedo, the artillery shell, the air-dropped bomb etc. The U.S. or USSR studied it intently, but never bothered developing it. Some Russian tests that unintentionally created Cobalt 60 because of the steels used in the bomb and whatever other equipment went up in the detonation have left some longer lived areas of contamination. However, like Cheyrnobyl, plants and wildlife are trucking along just fine for the most part there too.
Also, a UK test tried to use small amounts of cobalt as a "tracer" and yielded disappointing results that weren't useful, so it may not actually work as well in actual practice as feared.
Although, if we got a good direct hit on one or more of their reactors, that would be messier and have more sufficiently hot products that had longer half-lives too. Especially if it's a dirtier RBMK-like unpressurized graphite moderated reactor like Chernobyl was. And even then, while the Chernobyl exclusion zone isn't somewhere you'd want to live by modern first-world standards of health and longevity, but for most of it, the wildlife and a few squatters do just fine.
