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The detection of radioactive hot-spots and the identification of the radionuclides present have been a challenge for the security sector, especially in situations involving chemical, biological, radiological, nuclear and explosive threats, as well as naturally occurring radioactive materials. This work proposes a solution based on Machine Learning techniques, with a focus on artificial neural networks (NNs), in order to localise, quantify and identify radioactive sources. Firstly, the created RHLnet model uses observations of radiological intensity counts and corresponding localisations to estimate the number, location and activity of unknown radioactive sources present in a given scenario. Then, another model (RHIdnet) gets the gamma spectrum of the sources to perform the identification of the corresponding radionuclides. For this, a training data set composed of simulated data is used during the training process, and so, using algorithms with the models already trained, fast and accurate predictions are achieved, ensuring the reliability of such a NN-based approach. The proposed solution is tested in simulated and real scenarios, with multiple sources, providing a low number of limitations, related to possible false negatives and false positives. Besides, the results have shown that the algorithm is scalable for very large regions, as well as for very small scenarios. Single and multiple isotope identification on each sample is explored, highlighting the benefits as well as possible improvements. Thus, NNs have demonstrated the capability of being an emerging tool with the potential to make a difference in the nuclear field, by helping in the development of novel techniques and new solutions in order to safeguard human lives.

This work proposes a solution to identify the number of sources of radiation, as well as their respective intensities and locations based on data acquired by Global Positioning System (GPS) receivers and affordable radiological sensors, such as Geiger-M¨uller counters (GMC). An optimization algorithm is required to minimize the estimation error in terms of location, intensity and number of sources of radiation given all the intensity measurements acquired in different locations, taking into account the sensors’ models, background radiation intensity values and noise. Experimental results were achieved in a laboratory with controlled sources of radiation. The solution was also tested with real data gathered by a GMC connected to a mobile phone with a software application developed by the authors to synchronize the sensor readings with GPS data. The sensor and the mobile phone are attached to a quadcopter flying over the scenario with sources of radiation.

Sensor technologies will play a key role in the success of Remote Maintenance (RM) systems for future fusion reactors. In this paper, three key types of sensor technologies of particular interest in the robotics field at the moment are evaluated, namely: Colour-Depth cameras, LIDAR (Light Detection And Ranging), and Millimetre-Wave (mmWave) RADAR. The evaluation of the sensors is performed based on the following criteria: the types of data they provide, the accuracy at different distances, and the potential environmental resistance of the sensor (namely gamma radiation). The authors review the progress in making these three types of sensor capable of operating in Fusion facilities and discuss possible mitigations. Experiments are performed to demonstrate the pros and cons of each type of sensor by collecting data from radar, colour-depth camera and LIDAR, simultaneously. The paper concludes with a performance comparison between sensors, as well as discussing the possibility of combining them, fostering redundancy in case of failure of any individual sensor device.

The Diagnostics Slim Cassette (DSC) is a concept currently proposed for DEMO to host the microwave reflectometry diagnostic in a dedicated poloidal section, for the feedback control of plasma position and shape, providing also the radial edge density profile at several poloidal angles. This DSC, which is expected to house up to ∼100 antennas and waveguides, is to be integrated with the Breeding Blanket (BB) segments. Moreover, it is being designed with Remote Handling compatibility in mind to facilitate a "fast" exchange by Remote Maintenance (RM) when needed, fulfilling one of the aims of the Work Package Diagnostic and Control. In this approach the pre-assembled (banana-shaped) DSC modules are inserted/removed from the Upper Port (UP) of the Vacuum Vessel (VV) at least when the BB segments are replaced. Here the main constraints related to the integration of the DSC with the BB, the UP and the Equatorial Port are identified and discussed in detail, with a strong focus on the required RM operations inside the VV (in-vessel), providing solutions that can be adapted to present and future blanket and UP designs.

The Collective Thomson Scattering (CTS) diagnostic will be a primary diagnostic for measuring the dynamics of the confined fusion born alpha particles in ITER and will be the only diagnostic for alphas below 1.7 MeV [1]. The probe beam of the CTS diagnostic comes from a 60 GHz 1 MW gyrotron operated in a ~100 Hz modulation sequence. In the plasma, the probing beam will be scattered off fluctuations primarily due to the dynamics of the ions. Seven fixed receiver mirrors will pick up scattered radiation (the CTS signal) from seven measurement volumes along the probe beam covering the cross section of the plasma. The diagnostic is planned to provide a temporal resolution of ~100 ms and a spatial resolution of ~a/4 in the core and ~a/20 near the plasma edge where a = 2.0 m is the nominal minor radius of ITER. The front-end quasi-optics will be installed in an equatorial port plug (EPP#12). A particular challenge will be to pass the probing beam through the fundamental electron cyclotron resonance, which is located in the port plug (R=10.3 m) for the nominal magnetic field Bt = 5.3 T. Hence, particular mitigation actions against arcing have to be applied. The status of the design and specific challenges will be discussed.

In nuclear facilities, such as the experimental fusion reactor ITER, the cargo transfer operations can be performed by autonomous guided vehicles under remote supervision. In ITER, these vehicles can reach up to 100 tons and, with a rhombic-like configuration, have to move in cluttered scenarios. In case of failure, the vehicles have to be manually guided. This paper presents three solutions for the teleoperation of rhombic-like vehicles. Two set of devices were used to test each solution: one is based on a gamepad and the other is based on a joystick with a rotational disc specially designed for this purpose. The solutions were experimented by the developer and by 12 users without prior experience on rhombic-like vehicles. The experiments were performed in a software simulator that provides 2D maps of the test facility and simulates the kinematics of the vehicles in real time. The main conclusions are reported.

The remote handling (RH) plays an important role in nuclear test facilities, such as in ITER, for in-vessel and ex-vessel maintenance operations. Unexpected situations may occur when RH devices fail. Since no human being is allowed during the RH operations, a Multi-purpose Rescue Vehicle (MPRV) must be required for providing support in site. This paper proposes a design of a MPRV, i.e., a mobile platform equipped with different sensors and two manipulators with different sets of end-effectors. A human–machine interface is also proposed to remotely operate the MPRV and to carry out rescue and recovery operations.

The opening of cracks on the lateral sides of AFO's is a common problem due to the stress forces applied during the gait cycle. The problem can usually be prevented with the inclusion of structural reinforcements in the expected cracking zone of the AFO. This study proposes an approach to evaluate the effect of the applied reinforcements to the AFO's, quantifying the stress forces and deformation experienced by the orthotic device during the stance phase of the gait. For that, a CAD file of an AFO had to be crated and then edited using CAD software (ANSYS® SpaceClaim® Direct Modeler™) in order to create a geometry suitable to be analyzed by a CAE software (ANSYS® Workbench™™ with the Finite Element Method (FEM). Besides the digital model, different input conditions, such as forces (for dynamic conditions), supports (for static conditions) and material properties were defined and analyzed.

In this paper we present the results of the R&D work that has been performed on avoiding electron cyclotron (EC) gas breakdown inside the launcher transmission line (TL) of the ITER collective Thomson scattering (CTS) diagnostic, due to encountering the fundamental EC resonance, which is located inside the port plug vacuum for the baseline ITER magnetic field scenario. If an EC breakdown occurs, this can lead to strong local absorption of the CTS gyrotron beam, as well as arcing inside the ITER vacuum vessel, which must be avoided. Due to the hostile, restrictive, and nuclear environment in ITER, it is not possible to implement the standard method for avoiding EC breakdown - a controlled atmosphere at the EC resonance. Instead, the CTS diagnostic will include a longitudinally-split electrically-biased corrugated waveguide (SBWG) in the launcher transmission line. The SBWG works by applying a transverse DC bias voltage across the two electrically-isolated waveguide halves, causing free electrons to diffuse out of the EC resonant region before they can cause an electron-impact ionisation-avalanche, and thus an EC breakdown. Due to insufficient experimental facilities, the functionality of the SBWG is validated through Monte Carlo electron modelling.

Most mobile vehicle localization approaches rely on onboard sensors. However, whenever the installation of sensors onboard the vehicle is unfeasible, an alternative solution is to install them in the environment. One such environment is the ITER nuclear fusion reactor, where all maintenance operations have to be performed by remote handling, due to the radiation levels. This paper addresses the problem of vehicle localization in a structured environment, using a network of laser range nder sensors. The approach taken is based on: (1) the optimization of the sensor placement in the environment, aiming at the maximization of the area covered by the sensors and the redundancy of the sensor network, and (2) a probabilistic approach for vehicle localization. Two localization methods were evaluated: Extended Kalman Filter and Particle Filter. These two methods are compared, with respect to localization performance and robustness, both in simulation and using a real vehicle in a mock-up scenario.

The transfer cask system (TCS) is one of the remote handling systems that will operate in ITER, transporting heavy and highly activated in-vessel components between the tokamak building and the hot cell building. A motion planning methodology for the TCS was developed, providing smooth paths that maximize the clearance to obstacles and that incorporate manoeuvres whenever necessary. This paper presents the results of the TCS planning algorithm with trajectories computed for nominal operations. The length of the journey, the velocity, the time duration, and the risk of collision were evaluated individually for each trajectory. A summary of all results, conclusions and future work are presented and discussed.

This document states a method to optimize the coverage of a range finder multisensor network on an indoor environment. The problem arose from the need of a localization system for autonomous mobile robots, integrated with the building. The common approach for a localization system consists on sensors in the vehicle itself. In this case the vehicle is only an actuator and the sensory part is installed on the building. The localization system performance depends on the sensor placement, to enhance it, the sensor network must maximize the covered area. To solve the problem, an algorithm that maximizes the coverage areas is proposed. Given a scenario map, obtains the optimal coverage area multisensor placement. This paper presents also some results and proposals to future approaches to the problem.

In the thermonuclear experimental reactor ITER, a vehicle named CTS is designed to transport a container with activated components inside the buildings. In nominal operations, the CTS is autonomously guided under supervision. However, in some unexpected situations, such as in rescue and recovery operations, the autonomous mode must be overridden and the CTS must be remotely guided by an operator. The CTS is a rhombic-like vehicle, with two drivable and steerable wheels along its longitudinal axis, providing omni-directional capabilities. The rhombic kinematics correspond to four control variables, which are difficult to manage in manual mode operation. This paper proposes a Human Machine Interface (HMI) to remotely guide the vehicle in manual mode. The proposed solution is implemented using a HMI with an encoder connected to a micro-controller and an analog 2-axis joystick. Experimental results were obtained comparing the proposed solution with other controller devices in different scenarios and using a software plataform that simulates the kinematics and dynamics of the vehicle.

Remote maintenance operations in the experimental fusion reactor ITER may require vehicle localization, for which one of the proposed methods is based on a network of Laser Range Finder sensor measurements. This localization method requires an accurate knowledge of each sensor pose (position and orientation). A deviation in sensor pose can compromise localization accuracy thereby recalibration procedure for the sensor poses is often necessary. This paper studies several calibration algorithms based on ICP. Simulation and experimental tests were carried out for different maps and situations regarding sensor pose uncertainty. The conclusion proposes the best suited algorithms for each scenario.

The International Thermonuclear Experimental Reactor (ITER) project is a worldwide research experiment that aims to explore nuclear fusion as a viable source of energy for the coming years. Mobile robotics plays an important role in the remote handling systems that perform the maintenance operations in ITER. The Cask and Plug Remote Handling System (CPRHS) is one of the remote handling systems that transports heavy and highly activated in-vessel components between the Tokamak Building and the Hot Cell Building, the two main buildings of the ITER facility. The CPRHS has dimensions similar to an autobus, maximum weight of 100 tons, kinematics of a rhombic like vehicle (two drivable and steerable wheels) and has to move in cluttered environments. The main challenges described in this chapter are the definition of motion planning strategies that cope with the building maps and the cluttered environments. The algorithms were developed and implemented in a standalone application that receives CAD models of the buildings and returns the best trajectories, including reports of the most risky points of collision, and the swept volume of the vehicle along the missions. More than 700 trajectories were computed for different CPRHS types applied in the models of the real scenarios, crucial to proceed with the construction of the Tokamak Building.

Feature extraction and selection are important steps in the construction of a map to support the navigation of mobile robots in outdoor environments. The large amount of data acquired by the on-board sensors has to be reduced to retain only the crucial information for the navigation purpose. This procedure should be robust given the rough, dynamic and unpredictable conditions provided by outdoor scenarios. The paper discusses the use of different types of features and proposes a feature selection criteria aiming at building a topological map of the environment. The approach was tested with real data acquired in different types of outdoor scenarios.

This paper addresses the path following problem of a wheeled mobile robot with rhombic like kinematics (two drivable and steerable wheels) operating in cluttered environments. Four path following controllers are developed to steer the kinematic model of a rhombic like vehicle (RLV) along a desired path: three are based on feedback laws derived at a kinematic level with geometrical inspiration; the fourth is a nonlinear controller built upon a kinematic model of the vehicle using Lyapunov functions. By fully exploiting the kinematic capabilities of this type of vehicles, all the developed controllers are capable of performing under two situations: when both wheels follow the same path, or when each wheel follows a different path. Simulated and experimental results are presented in the paper to illustrate the performance of the controllers. The main conclusions of these controllers are summarized, leading to a possible application in the vehicles that will operate in the remote handling missions of the International Thermonuclear Experimental Reactor (ITER).

Rhombic like vehicles are characterized for high maneuverability in cluttered environments. This type of vehicles will be used on remote handling operations of maintenance in the International Thermonuclear Experimental Reactor (ITER). Previous work was done in motion planning using Constrained Delaunay Triangulation for rhombic like vehicles operating in ITER. This paper shows that the integration of Fast Marching Square improves the motion planning methodology, decreasing also the computational effort, which can be applied not only in ITER but also in other complex and cluttered environments. Simulated results are presented comparing the initial and the improved motion planning.

This paper describes a study of different remotely operated driving modes applied to rhombic like vehicles using the digital buttons and the analog sticks of a generic game controller device (e.g., joysticks and gamepads). The performance of the different modes was evaluated using a software simulator and a 2D model of the Tokamak building of ITER. Several experiments were performed taking into account relevant parameters, such as the distance to the obstacles and accelerations. An optimal approach for a real implementation with a rhombic like vehicle prototype is proposed and discussed.

This paper proposes a new path optimization method to improve feasibility and optimality of rough collision-free paths provided by global planners. Inspired on the dynamics of rigid bodies, this method redefines the elastic bands framework to explicitly handle vehicle geometric constraints and explore the high maneuvering ability of rhombic vehicles. The proposed method was tested as a post optimization technique on global path solutions planned for a large transporter that will operate in the International Thermonuclear Experimental Reactor (ITER). Presented results show the proficiency of this method on handling feasible and reliable paths in cluttered scenarios such as those in ITER.

The Transfer Cask System (TCS) is one of the adopted Remote Handling (RH) components to operate on the International Thermonuclear Experimental Reactor (ITER). During maintenance operations, the TCS is expected to move between specified locations in different levels of the Tokamak Building (TB), transporting heavy and highly activated components while meeting competing safety requirements. This paper proposes a complete motion planning methodology, covering path optimization and trajectory evaluation for static but tightly constrained scenarios. The optimization scheme is inspired on the elastic bands method, and takes into account geometric and kinematic robot considerations.

This paper proposes a set of navigation strategies to cooperatively localize a team of robots by applying a Particle-Filter approach. The main mission consists in exploring unknown, isolated and unstructured scenarios, where no Global Positioning System is available. By means of the cooperative localization technique and a behaviour based controller the robots have to return to the initial configuration. The proposed approach relies on distance and orientation measurements between the individual robots, and between the robots and a fixed active beacon. Simulation results are presented.