Visualization of a dismantling environment for an evaluation of a worker’s dose during the decommissioning of KRR-1&2

The purpose of this paper is to provide a basis for an optimization of a dismantling process of a research reactor and nuclear facility. An optimization of a dismantling process should be at the beginning of a study for an evaluation of the radioactivity inventory and the safety of the workers. Many countries have conducted an optimization to achieve a shortened dismantling schedule, a reduction of the amount of waste, and cut down on the decommissioning by using computer graphics such as animation, simulation, and virtual reality. In the present study, we propose methods for identifying the existence of radioactivity which is contained in the dismantled objects and for evaluating a worker’s dose through a simulation. To evaluate a worker’s external dose under a virtual dismantling environment generated by computer graphics, the shape of the thermal column horizontal door was created by 3D CAD and the radiation dose surrounding the door was calculated by using MCNP-4C. An animation that can demonstrate a dismantling procedure according to a dismantling scenario was produced. For matching the radiation dose, which was calculated by MCNP-4C with an area where workers are dismantling a door, a simulation module was developed which could show a worker’s external dose in real-time. The result from the distribution of the radioactivity enables us to specify where the most contaminated part of the dismantling objects is. In the animation, a virtual worker demonstrated a dismantling activity procedure as a chosen scenario. In the simulation, a worker’s exposure dose rate in real-time has been evaluated.