The following was received from the State of
Tennessee via email:
The door to a J. L. Shepherd Mark 1-68 irradiator containing 10,000 curies (assayed 2/11/2002) of Cesium 137, being used to irradiate mice, would not open. The source was determined to be in the safe position. St. Jude trustworthiness-approved radiation safety and biomedical engineering (BME) personnel responded and attempted to extract the mice without success. A call to the licensed service representative went unanswered. The Associate Radiation Safety Officer who was present approved BME [personnel] to take measures to disengage the door. This involved breaking security seals on the timer control mechanism and door interlock box. Also, the lock on the interlock box was cut since the key was not present. Strict radiological controls were employed including; badging all personnel, survey meter present, continuous health physicist presence, confirmation of source in safe position, and unplugging irradiator to ensure the source could not move. The animals were extracted without incident. The irradiator was locked and removed from service. The service representative came March 11, 2015, and repaired the unit such that it was fully operational. Evidently, the door interlock switch that had been replaced in January had failed.
TN Event Report ID Number: TN-15-036