High Quality Content by WIKIPEDIA articles! The Sodium Reactor Experiment was a pioneering nuclear power plant built by Atomics International at the Santa Susana Field Laboratory, nearby Simi Valley, California. The reactor operated from 1957 to 1964. On July 12, 1957 the Sodium Reactor Experiment became the first nuclear reactor in the United States to produce electrical power for a commercial power grid by powering the nearby city of Moorpark. In July 1959, the reactor suffered a serious incident in which the reactor core was damaged causing the controlled release of radioactive gas to the atmosphere. The reactor was repaired and restarted in September 1960. In February 1964, the Sodium Reactor Experiment was operated for the last time. Removal of the deactivated reactor was completed in 1981. Recent competing technical analysis of the 1959 incident has produced contrasting conclusions regarding the types and quantities of radioactive materials released. Members of the neighboring communities have expressed concerns about the possible impacts to health and environment from the incident. In August 2009, the Department of Energy hosted a community workshop to discuss the 1959 incident.