Accident Investigation of the June 17, 2012, Construction Accident - Structural Steel Collapse at the Overpack Storage Expansion #2 at the Naval Reactors Facility

August 24, 2012

This report documents the Naval Reactors investigation into the collapse of a partially-erected spent fuel storage building, Overpack Storage Expansion #2 (OSE2), at the Naval Reactors Facility. The Accident Investigation Board inspected the scene, collected physical and photographic evidence, interviewed involved personnel, and reviewed relevant documents to determine the key causes of the accident. Based on the information gathered during the investigation, the Board identified several engineering and safety deficiencies that need to be addressed to prevent recurrence.