Article on sightings at LLNL.

On April 1, 2021, a Lawrence Livermore security supervisor reported an employee’s early morning sighting of “a possible drone hovering 50-75 feet off the ground in the buffer zone. Due to the darkness I only saw the red and white lights.” The supervisor consulted with a construction crew and drone operator in the area. Neither had been flying a drone at the time.

One report categorized as “Incident: Suspicious Occurrence” was recorded by a supervisor on April 30, 2019. It involved security escorts near Lawrence Livermore’s building 815. Having spoken with the escorts, the supervisor reported, “They both said, ‘I saw a round silver drone flying around the Process Area and periodically stopping and hovering for several seconds. Once it continued it flew to the north of my location and stopped and hovered for several more seconds. It flew over that area for several minutes and departed south east. It was really high up and it looked like it was just under the clouds.'” The supervisor adds, “The drone like object was flying at a distance and height that made identification of the object impossible for the employees.” The supervisor then contacted another employee “who said there was no scheduled flights for Site 300 today.” The supervisor then ordered a security sweep that found no one who might have been operating a drone.

Note the description in the second quote of it being a "round silver drone"

Edit: Additional reporting from The Debrief and the incident report for the 2019 encounter.