Fallout 3 locations project
VAPL-84 Power Station
Go straight north from the RobCo Facility until you come upon some power lines. Turn left and follow the power lines and you will find the station.
A fenced-in power station with a tractor trailer next to it. The tractor trailer contains 1 Mini Nuke, three ammunition boxes, two metal boxes and assorted custom weapon parts. It's also possible to find Stealth Boys and missiles in and around the boxes.
There seems to be a Scavenger post near to the station next to the burning barrel. The barrel is a spot which will spawn various types of NPC encounters upon entering the boundaries of the spawn zone, the scavenger encounter simply being the most common, or perhaps simply the first default iteration of the encounter routine. See Fallout 3 random encounters.
There is also a group of respawning raiders here, but they usually fight with (and are killed by) a Yao Guai in the vicinity (two Raider corpses were lying where blood stains on the ground could be found. Possibly they are spawned dead to give the whole scene the appearance that they might have tried to catch the Yao-Guai and failed miserably). Be wary of a random Deathclaw or two in this area, as well.