Crystal River Unit 3 is currently shutdown for a planned refueling and
steam generator replacement outage. During containment building concrete removal activities to create a construction opening to support
steam generator replacement, a separation in the concrete was discovered in the vicinity of the construction opening near the periphery of the containment. The Crystal River Unit 3 containment is a steel lined, post tensioned concrete structure nominally 42 inches thick. Post tensioning is achieved utilizing an outer array of horizontal tendons immediately adjacent to an inner array of vertical tendons. The separation is generally in the plane of the horizontal tendons. Inside the separation is 30 inches of concrete and the steel liner plate. This condition has been evaluated relative to current plant conditions and found to represent no degradation in safety. Crystal River Unit 3 personnel in conjunction with industry experts are currently performing a detailed analysis of this separation to determine the cause, extent of condition, the impact on the containment building function and any required repairs prior to plant restart. Operating experience reports are being prepared to share our information with the industry. The station will provide updates as we gain more information concerning this issue.
The licensee notified the NRC Resident Inspector.