This work presents a design for nuclear radiation detection and monitoring system in a nuclear facility based on wireless sensor networks (WSNs). Energy efficiency is a critical factor in designing WSNs where a sensor node is small with limited power resources. A reliable WSN must be energy efficient to maximize its lifetime. Media access control (MAC) protocols are essential for the energy-efficiency objectives of WSNs as they directly control the most energy consuming part of a sensor node communications over the shared medium. Different MAC protocols for WSNs are presented. This search will explain the important role of MAC protocols for energy saving and why currently conventional protocols don't fit for the actual requirements. A comparison between two MAC protocols, IEEE802.11 and sensor MAC (SMAC), is presented using network simulator-NS-2.35. Then their performance will be compared to each other. SMAC outperforms IEEE802.11 in total energy conservation by approximately 21%. Power saving is the main aim in the design of nuclear radiation WSN to guarantee more life time for the network.