As reported by AvHerald, which matches the activity on the scene at ANC...
Incident: United B788 over Bering Sea on Sep 19th 2013, flaps indication
By Simon Hradecky, created Friday, Sep 20th 2013 19:07Z, last updated Friday, Sep 20th 2013 19:07Z
A United Boeing 787-800, registration N27901 performing flight UA-139 from Denver,CO (USA) to Tokyo Narita (Japan), was enroute at FL400 over the Bering Sea about 500nm west of Anchorage,AK (USA) when the crew received an abnormal indication for the flaps, declared emergency, turned around and diverted to Anchorage. The aircraft entered a holding to work checklists and prepare the aircraft for landing in the vicinity of Anchorage, when the aircraft began to position for the approach the airport halted all other movements. The aircraft landed safely on Anchorage's runway 07R at a substantially higher than normal speed (around 190 knots over ground) about 90 minutes after turning around. The crew vacated the runway but reported hot brakes for the right hand side, emergency services on standby checked the brakes and cleared the aircraft to continue to the apron with emergency services in trail.
The remainder of the flight was cancelled.
Ferried to DEN on Friday as UA 6860