Development of Criticality Accident Alarm System to Ensure Safe Retrieval of Spent Nuclear Fuel from Lepse Floating Maintenance Base

The paper presents basic results of development of a criticality accident alarm system to ensure safe retrieval of the spent nuclear fuel from the Lepse Floating Maintenance Base. The key features and engineering aspects of the system design are described. Locations of criticality detector units and selected alarm level settings are justified, hazardous area boundaries were identified, and parameters to identify inadequately protected zones were calculated. The SRKS-01D criticality accident alarm system by SPC “Doza” was selected as base equipment. The system was commissioned in 2019 and has been successfully operated for more than 6 months.