While still in domestic airspace; a B747-400 dumped fuel and diverted due to a fuel leak.

Narrative

All operations were normal for preflight and taxi out. The takeoff was normal and just prior to top of climb; I headed back to the bunk room for my rest break. Approximately 4 hours after I had started my break; the flying crew woke me. I got dressed and stepped into the cockpit to discover that we were in a diversion situation due to a fuel leak. I sat down as the primary relief pilot; and read over the divert checklist and asked the flying crew to verify that the different considerations had been covered. The flying crew was in the process of dumping fuel. The entire crew was briefed on the SID; and the visual Runway. The descent and arrival were normal and the CFR team was standing by. After landing and clearing the runway; the CFR team inspected the aircraft for fuel leaks and none were noted. We proceeded to the gate where we complied with all checklists; and were greeted by maintenance and CFR. We gave everyone the required information and went to Flight Operations to fill out this report.