my take:

jellyfish: stingers, tentacles, feelers, drifters, instinctive (intel gathering groups/units/individuals?)

nuclear power plant: produce power(literal and metaphorical? political?), produce fuel for bombs(explosive information dangerous to DS if revealed?), require cooling(insulation to prevent explosive information being revealed?), failure of cooling can cause meltdown(leak of information causing immediate and cascading(runaway) damage to DS elements?)

Cooling Pipe: Opening, intake, entry point, access point, insulation, thermal control. Being clogged (something infiltrating insulation system, limiting or preventing means of insulation of DS from performing its role? prevention from replenishing/renewing insulation of explosive info production point? Making it harder to hide?)

Around the world: Global, international, unlimited, all encompassing? Effect is global?