Abstract: An underwater nuclear material reconnaissance system includes an underwater vehicle propelled/steered by a plurality of propulsion pods distributed thereabout. The underwater vehicle includes nuclear material sensors for generating sensor data indicative of the presence of nuclear material, a tunnel thruster for providing vertical thrust for the underwater vehicle, and a bi-directional communications cable deployable from the underwater vehicle. A remotely-located communications base station coupled to the bi-directional communications cable transmits control commands to the underwater vehicle and receives sensor data transmitted from the underwater vehicle.