Remote search for gamma sources at the dry storage unit 3A in Andreeva bay and the determination of their dose rates during activities for improvement to the radiological environment

The remotely controlled replacement of the concrete covering of the spent fuel dry storage unit 3A with a new iron horizontal biological shielding was carried out during works aimed at the improvement of the radiological environment at the NWC ?SevRAO? - Branch of FSUE ?RosRAO?, Andreeva Bay, Murmansk Region. Video control systems, a BROKK robotic manipulator, HIAB manipulator crane, gamma detectors of the ASCRO radiation monitoring system, and a CARTOGAM gamma camera were employed. A CARTOGAM gamma camera was used in all stages of the work involving high radiation levels for the remote location of the most dangerous gamma radiation sources and the evaluation of their dose rates. Gamma detectors of the ASCRO radiation monitoring system were located at several spots of the dry storage unit 3A in order to control the radiation situation. The use of the ASCRO and CARTOGAM has allowed us to avoid unauthorized exposure of the staff involved in the operations at the dry storage unit 3A site. U cilju unapredjenja radioloske sredine izvrsena je daljinski upravljana zamena betonskog prekrivaca skladisne jedinice 3A isluzenog goriva novom, gvozdenom i horizontalnom, bioloskom zastitom. Skladiste se nalazi u Zalivu Andrejeva, u Murmanskoj oblasti. Korisceni su video sistemi, BROKK robotski manipulator, HIAB kran, gama detektori iz ASCRO sistema za monitoring zracenja i CARTOGAM gama kamera. CARTOGAM gama kamera koriscena je u svim fazama posla, ukljucujuci visoke nivoe zracenja, za daljinsko lociranje najopasnijih izvora gama zracenja i procenu njihovih jacina doza. ASCRO gama detektori bili su postavljeni na nekoliko pozicija oko skladisne jedinice 3A za nadgledanje nivoa radijacije. Korisceni ASCRO detektori i CARTOGAM kamare omogucili su da se izbegne neovlasceno izlaganje zracenju osoblja koje je ucestvovalo u radu.