It can be found on the ground level near a skeleton, just south of Sunstone Tower roof, in a duffle bag.
Jesus, this place is a hellhole. I heard it was bad from some of the guys coming back, but... Jesus. Henriksen bought it when one of those unexploded warheads went off and Jenkins... those things got him. I don't know what they were exactly - ghouls, maybe, but nasty fuckers. LT thinks they were drawn by the explosion that killed Henrikson. I think we're all gonna die here.
This journal is 1 of 10 the player character must find to complete the "Nostalgia" challenge.