David Sereda has sent us a video clip, shot in 2004, which he says shows a Gamma radiation burst coming from the Palo Verde Nuclear Facility. The burst is the blue flash that occurs at the beginning of the clip, the second scene is an establishing shot.
Sereda explains the significance: "This very rare event captured on video proves that concrete barrier, nor steel can stop harmful gamma radiation from escaping the confines of a nuclear reactor. Gamma radiation is invisible to the human eye. With precise timing and optics, gamma radiation can be captured on video or film."