A radioactivity detector sounded the alarm while workers were at a nuclear fuel facility in Tokai Village, Ibaraki Prefecture, north of Tokyo. Local officials say there was no impact on the environment. The Japan Atomic Energy Agency says the alarm went off at around 2:30pm on Wednesday at its Nuclear Fuel Cycle Engineering Laboratories. The agency says nine workers were present at the site, and none of them suffered radiation exposure, according to NHK. The prefecture says there is no change in figures from the monitoring posts that measure radioactivity levels in the surrounding areas. The alarm sounded in a facility at the laboratories that was previously used to produce MOX fuel, a mixture of plutonium and uranium. Production there ended in 2001. The work that was underway reportedly related to the recovery of nuclear fuel materials stored in the facility, and the dissembling of equipment.