The development of consumer grade electronics such as mobile phones and wearable devices, has lead to significant advances in a variety of low cost commercial off-the-shelf (COTS) technologies. Areas of advances triggered by the consumer electronics boom include (but are not limited to) battery technology, low cost and power efficient computation, low cost inertial measurement sensors, and low cost imaging sensors. This has in turn encouraged a significant growth in the functional capability of robotics in general, with particular impact on low cost robotics. In recent years industry has looked to take advantage of low cost robotics, with an increasing desire to deploy systems into hazardous environments, replacing jobs that are considered dangerous, which would otherwise be undertaken by human operators at significant monetary and time expense. One such industry that is increasing the use of low cost robotics is the nuclear decommissioning industry. The work in this thesis is therefore directed towards aiding the decommissioning of the Sellafield nuclear power station in the United Kingdom, and the Atomic Weapons Establishment (AWE), also in the United Kingdom. However the work can be extended to other sites around the world in their decommissioning phase, such as the Fukushima Daiichi power station in Japan. The work presented however has broader applications in low cost robotics, autonomous exploration, computer vision, scene reconstruction and radiation surveying. This thesis discusses low cost, robotic exploration of unknown environments, from both a 3D environment exploration and radiation surveying point of view. Novel algorithms are proposed to facilitate the autonomous exploration of 3D environments. The development, construction and deployment of mobile robotic platforms for radiation survey and environment exploration are also documented. Novel approaches to 3D point cloud repair are discussed and evaluated against manual repair of said point clouds, and a novel algorithm for determining the best repair method for a given situation is also proposed. A white trial (non-active, observed test) of the CARMA EDD (Continuous Autonomous Radiation Mapping Assistant, Extended Deployment Disposable) robot was conducted towards the end of this PhD, with a deployment into an unknown environment for radiation survey and 3D exploration at an AWE facility scheduled for Q3 2019.