Assessment of contamination distribution of "Monju", 6; Assessment of activation of the ex-vessel fuel transfer machine

Kawaguchi, Yotaro*; Kinoshita, Takuma*; Kishimoto, Yasufumi*; Hanaki, Shotaro  ; Mashimo, Ryutaro; Hayashi, Hirokazu 

Dismantling in radiation-controlled area is planned in phase 3 of the "Monju" decommissioning program, but an assessment of contamination of the facilities is essential before starting the dismantling. The Ex-Vessel fuel Transfer Machine, a unique facility of "Monju" that transfers core components between other fuel handling facilities. Due to neutrons generated from fuel, the structural materials are activated. The radioactivity of the ex-vessel fuel transfer machine was assessed using the same methodology as the reactor's evaluation. The neutron flux distribution and activation levels were evaluated using a 2D RZ system. Additionally, it was confirmed that the activity of activation products is at most at L3 levels, and in most areas, it is below the clearance levels.