VNU Journal of Science Mathematics – Physics, Vol 37, No 3 (2021) 51 60 51 Original Article Steady State Calculations of the PWR MOX/UO2 Core with the Monte Carlo Code MCNP6 Nguyen Thi Dung1, Tran Viet Phu1, Donny Hartanto2, Luu Thi Lan3, Mai Huu Thuan4, Pham Nhu Viet Ha1,* 1Institute for Nuclear Science and Technology, VINATOM, 179 Hoang Quoc Viet, Hanoi, Vietnam 2University of Sharjah, P O BOX, 27272, Sharjah, United Arab Emirates 3Vietnam National Cancer Hospital, 30 Cau Buou, Thanh Tri, Ha[.]