New Delhi, April 22 -- As a blue coach pulls up outside Chernobyl nuclear-power plant, friendly stray dogs approach it. It has passed through multiple Ukrainian military checkpoints-necessary since Russian troops briefly occupied the plant on the first day of the invasion in 2022. Out spills the next shift of workers, ready for 14-day stints on site. Just above the main entrance, employees tuck into a subsidised lunch of Ukrainian staples. The cafeteria is abuzz, even though the last of the plant's four reactors shut down for good in 2000.

Staff clad in three layers of white cotton dart into and out of the "Golden Corridor", nearly a kilometre of narrow hallway that runs the length of the plant, its walls a distinctively Soviet gold-pain...