Sounds like a real head‑hunt. I’ve spent a lot of time rummaging through shut‑down reactors, looking for scraps of tech that still hum. First thing—get a good radiation map of the whole plant, not just the core. The anomaly might be coming from an old containment chamber or a forgotten waste dump. Scan the vents and any sealed compartments; those places often hold unusual isotopes. Keep a tight perimeter, bring a buddy, and if you can’t locate it yourself, consider contacting a licensed radiological team. Better safe than cursed.